Minproc Technology Pty Ltd v Commonwealth Scientific and Industrial Research Organisation
[1998] APO 1
•9 January 1998
official notice
decision of a delegate of the commissioner of patents
Application : No. 646510 in the name of Minproc Technology Pty Ltd
Title: Direct Sulphidization Fuming of Zinc
Action: Opposition under section 59 of the Patents Act 1990 by Commonwealth Scientific and industrial Research Organisation
Decision: Issued .
Abstract
Claims 1, 14 and 24 and the claims dependent thereon were found to lack novelty over patent application number 79186/97 by CSIRO. The feature of generating a proportion of FeO from iron sulphide was an inevitable consequence of carrying out the process described in the CSIRO specification. The claims were not limited to the features relied on in the applicant’s evidence to distinguish the invention from the citation.
Claim 13 was found to be novel and inventive. None of the documents cited suggested carrying out freeboard reactions using a sub-stoichiometric amount of oxygen to partially oxidize a proportion of iron sulphide.
The claims fail section 40 because they do not define the invention. The requirement to maintain sufficient sulphide in the bath to control the partial pressure of oxygen is not defined.
Claim 25 is not clear as it conflicts with claim 24 to which it is appended.
The parties given 21 days from the date of the decision in which to file submissions on costs.
patents act 1990
decision of a delegate of the commissioner of patents
Re:Patent Application No. 646510 by Minproc Technology Pty Ltd and opposition by Commonwealth Scientific and Industrial Research Organisation under section 59 of the Patents Act 1990.
background
Minproc Technology Inc filed patent application 87612/91 on 28 October 1991. The application is based on two earlier provisional specifications and claims an earliest priority date of 14 November 1990. The application was advertised accepted on 24 February 1994 as application 646510. Minproc Technology Inc has assigned the application to Minproc Technology Pty Ltd (hereafter referred to as the applicant).
Commonwealth Scientific and Industrial Research Organisation (hereafter referred to as the opponent) opposed the application on 23 May 1994. The applicant proposed amendments to the complete specification on 20 August 1996, following the completion of service of evidence. The Commissioner accepted the amendments on 30 April 1997. The opponent and the applicant subsequently filed further evidence and evidence in response, respectively.
I heard the matter in Melbourne on 27 August 1997. The applicant was represented by Mr Barry J. Hess of Counsel. Mr Hess was assisted by Mr Colin J Oberin, Patent Attorney of Oberins Arthur Robinson & Hedderwicks, Melbourne. The opponent was represented by Mr Bruce Caine of Counsel. Mr Caine was assisted by Mr Michael Angliss, Patent Attorney of Davies Collison Cave, Melbourne.
Evidence
The evidence in support included declarations by:
Peter Harold Huntsman, Patent Attorney of Davies Collison Cave, dated 1 September 1994. This declaration was accompanied by exhibits PHH-1 to PHH-17. These exhibits comprised the prior art documents relied on by the opponents in the opposition.
Denise Anne Sthradher, a Librarian of the CSIRO Division of Minerals and a further declaration by Mr Huntsman. These two declarations sought to establish the publication dates of exhibits PHH-1 to PHH-17.
Viruthiamparambath Rajakumar, dated 24 April 1995 (hereafter referred to as Rajakumar #1). Dr Rajakumar stated that he is a Senior Research Scientist, Senior Project Manager, Metal Production and Refining, CSIRO Minerals, Clayton Victoria. This was the main declaration in support of the opponent’s case.
John Millice Floyd, Chief Executive Officer of Ausmelt Limited. This declaration made some brief comments in support of the Rajakumar declaration and included some comments on the publication of PHH-14 and PHH-15.
The evidence in answer included declarations by:
John Graham Whellock, one of the inventors of the opposed application. Whellock states that the invention was the result of efforts to find a way to economically upgrade a source of zinc known as the Colquiri tailings dump in Bolivia. Because the high iron content of the feed would lead to jarosite disposal problems, a hydrometallurgical process was not feasible and a thermal process appeared to offer better promise. Also, no significant quantities of coal are available in Bolivia. Although charcoal is available, it is expensive and very light and would be unsuitable for use in a slag fuming process. According to Whellock, the test work which resulted in the making of the invention which is the subject of the opposed application did not involve the use of coal or carbon as a reductant. Whellock further states that the original concept on which the process was developed was that zinc sulphide would sublimate if sufficient heat could be applied. He also states that it was logical to try and avoid the zinc oxidising to form zinc oxide, as this is known to cause difficult slag problems in pyrometallurgical processes. Hence the need for a carrier gas which initial testing indicated could be nitrogen or even air since the required oxygen partial pressure is controlled by the presence of sulphide.
Keith Edward Ramus, a consulting metallurgist, dated 13 November 1995 (hereafter referred to as Ramus #1). According to Mr Ramus, he spent several weeks during April 1995 in Bolivia at the pilot plant operating the Minproc zinc fuming process which is the subject of the opposed specification.
Evan Kirby, Manager Metallurgy, Minproc Engineers Limited, dated 13 November 1995 (hereafter referred to as Kirby #1). Kirby has also worked at the Bolivian plant.
Denby Harcourt Ward, Managing Director of Denby H Ward Pty Ltd which provides consultant services in non-ferrous, extractive metallurgy. Mr Ward states he is independent of the parties in this matter.
Thomas Ronald Albert Davey, Managing Director of Metacon Consulting Services. Dr Davey is co-author of the paper exhibited as PHH-2.
The evidence in reply comprised a declaration by Viruthiamparambath Rajakumar, dated 7 June 1996 (hereafter referred to as Rajakumar #2).
The further evidence filed by the opponent comprised a declaration by Viruthiamparambath Rajakumar, dated 24 April 1995 (hereafter referred to as Rajakumar #3).
The evidence in response filed by the applicant included declarations by Evan Kirby dated 23 July 1997 (hereafter referred to as Kirby #2) and Keith Edward Ramus dated 24 July 1997 (hereafter referred to as Ramus #2).
specification
The specification opens by stating that the present invention relates to the direct sulphidization fuming of zinc and more particularly to the treatment of zinc bearing feed materials. The description then discusses some of the known ways of recovering zinc or zinc oxide. These include roasting in an oxidizing environment, pressure leaching operations such as the Sherritt-Cominco process, fuming from slags where zinc oxide is recovered by reducing the zinc in the slag at high temperature to zinc vapour by the addition of reducing agent to the slag, and by making use of the Waelz kiln in which the zinc bearing feedstock is passed with coke through a high temperature horizontal kiln in which reduction of the zinc oxide to zinc vapour occurs. The description goes on to state:
“Yet another proposed prior art process involves the treatment of lead-zinc complex sulphide ores or concentrates by a reductive fuming process. The process as proposed in Australian Patent Application AU-B-79186/87 (CSIRO) involves adding the feed to a bath of molten matte which is overlaid by a slag layer; agitating and heating the bath; and adding a reductant to the bath. The addition of a reductant to the bath is unnecessary and undesirable from the point of view of excess reagent use and handling excessive heat loads in downstream equipment. In addition the recovery rates of the CSIRO process are relatively low and operating costs high and it is not clear whether the process could be applied in the absence of significant amounts of lead.”
The specification then mentions two objects of the invention, which are to ameliorate the problems of the prior art. This is followed by statements generally in the same terms as the claims. The specification continues:
“It appears that the liquid state of pure zinc sulphide does not occur in the range of pressures normally employed in pyrometallurgical processing. However, it is possible to obtain liquid mattes of iron (FeS) containing significant amounts of zinc sulphide. We have now found that by maintaining an agitated matte/slag system containing iron sulphide, at sufficient temperature with the iron sulphide matte being intimately mixed in the bath with the slag phase zinc can be fumed very satisfactorily without recourse to reductant addition.
It is not clear whether zinc sulphide that is fumed from a molten intimate mixture of matte and slag is separate zinc and sulphur vapours or a zinc sulphide combined in the vapour form. Since iron sulphide does not fume significantly itself, it is possible to make a very efficient separation of zinc from iron using this method.
The operating conditions such as temperature and partial pressure of oxygen must be maintained in order that zinc oxide which is highly infusible is not produced in the molten bath during fuming. On the other hand, it is possible to oxidize a proportion of the iron sulphide that is present either through oxygen or air from combustion or from other oxidic materials in the charge. However, it is important to maintain sufficient sulphide in the bath to control the partial pressure of oxygen as it is this mechanism which leads to the direct volatilisation of the zinc vapour or zinc sulphide vapour without the need for a reductive step.
By converting a proportion of the iron to its oxide some heat is liberated in the molten bath, and the presence of the FeO so formed is often beneficial for the fusibility of the slag phase which is formed in conjunction with the matte in the bath.”
The specification includes 26 claims, as follows:
A process for the treatment of zinc sulphide of other zinc bearing feed materials in conjunction with an iron sulfide containing mineral or compound to effect a separation of zinc from iron by fuming of either zinc and sulphur vapour or zinc sulphide vapour, said vapour being stripped and transported by a carrier gas from the mineral or a molten matte formed from the mineral which process is operated at a temperature in the region of 1250 to 1400 °C and at a partial pressure of oxygen in the region of 10-7 to 10-11 bar, and which process is conducted in the presence of the liquid matte phase which contains at least iron sulphide and which is intimately mixed in a bath with a slag phase and wherein a proportion of FeO is generated from the iron sulphide.
Claims 2 to 12 are dependent on claim 1.
A method in which a zinc oxide or zinc sulphide bearing material and including some iron sulphide is partially oxidized in the freeboard of a furnace through the use of air and/or oxygen in substoichiometric ratio so that a matte bath is formed which is sparged by a carrier gas injected from above by lance or through tuyeres or nozzles and zinc and sulphur vapour or zinc sulphide vapour leave the reaction zone and molten bath in the total gas flow wherein the bath temperature is in the region of 1250-1400 °C and the partial pressure of oxygen in the bath is in the region of 10-8 - 10-12 bar and a proportion of FeO is generated from the iron sulphide.
A process for the treatment of a zinc bearing feed material being a sulphide mineral in conjunction with an iron sulphide mineral to form a molten matte from which zinc sulphide either as zinc and sulphur vapour or a zinc sulphide vapour is fumed directly by the stripping action of a carrier gas which process is operated at a temperature in the region of 1250 to 1400 °C and at a partial pressure of oxygen in the region of 10-8 to 10-12 bar and wherein the molten matte is intimately mixed in a bath with a slag phase and a proportion of FeO is generated from the iron sulphide.
Claims 15 to 23 are dependent on claim 14.
A process for the treatment of a zinc sulphide containing feed material to effect a separation of zinc from iron which process comprises fuming from a molten bath containing iron sulphide, said molten bath comprising an intimate mixture of matte and slag at a temperature of approximately 1300 °C and at a partial pressure of oxygen in the region of 10-8 bar wherein a proportion of FeO is generated from the iron sulphide, stripping and transporting the fume by a carrier gas and separating zinc from the fume.
Claims 25 and 26 are dependent on claim 24.
Decision
The grounds of opposition listed in the statement of grounds and particulars are novelty, obviousness and section 40. The particulars list seventeen documents under the grounds of novelty and obviousness. These were filed in evidence as exhibits PHH-1 to PHH-17. At the hearing Mr Caine stated that exhibits PHH-3 to PHH-17 were not individually citations, but formed part of the common general knowledge. The opponents case in regard to novelty and inventive step was based primarily on exhibits PHH-1 (Australian Patent Application 79186/87 by CSIRO, published 24 March 1988) and PHH-2 (Davey TRA & Turnbull AG - “The Direct Smelting of Zinc Sulfide Concentrate”, Paper to the Australian Japan Extractive Metallurgy Symposium, Sydney 1980, pages 23-29 (The Australian Institute of Mining and Metallurgy)). According to the Sthradher declaration, this document has an accession stamp dated 3 August 1981 from the library of the CSIRO Division of Minerals. The arguments of the parties went mainly to the technical facts of the case and whether or not certain features were included in the claims. I will therefore set out the submissions in detail.
Submissions
Mr Caine commenced his submissions on behalf of the opponent by saying that there was a difference between what was described as the invention, what was claimed, and the evidence of what the invention is. He stated that these amounted to two or three different things. The question to be answered, according to Mr Caine, is what is the proper scope of the claims. He referred me to the following paragraphs in The Mullard Radio Valve Co., Ltd v Philco Radio and Television Corporation of Great Britain, Ltd and Others (1936) 53 RPC 323 at 345:
“A patentee may make a most meritorious discovery and may give an entirely adequate description of his inventive idea and of the manner of putting it into practice, but when he comes to formulate the claim to his invention he may claim a monopoly wider in extent than is warranted by what he has invented.”
and at 347:
“The consideration which the patentee gives to the public disclosing his inventive idea entitles him in return to protection for an article which embodies his inventive idea but not for an article which, while capable of being used to carry his inventive idea into effect, is described in terms which cover things quite unrelated to his inventive idea, and which do not embody it at all.”
Mr Caine argued that much of the applicant’s evidence referred to features that were in the description or in the commercial process (the Bolivian plant) but which were not present in the claims.
Mr Caine referred me to clause 13 of Rajakumar #1 and page 3b line 31 to page 3c line 4 of the description. Dr Rajakumar states that he understood from this paragraph it is the absence of reductant which distinguishes the invention described from the CSIRO application. At clause 16 Rajakumar states that he understood from the description of the opposed application that it is important to maintain sufficient sulphide in the bath to control the partial pressure of oxygen in order to operate the process to which the opposed application is directed without the need for a reductive step. At clause 24 Rajakumar states that claim 1 is silent with regard to the need to maintain sufficient sulphide in the bath. Mr Caine also referred me to paragraphs 15 and 16 of Rajakumar #2, which also highlight Rajakumar’s understanding from the description and from the evidence in answer that it is important to maintain sufficient sulphide in the bath to control the partial pressure of oxygen in order to operate the process of the opposed application. Mr Caine argued that there was no requirement in the claims that there be any particular amount of sulphide or an amount sufficient to control the partial pressure of oxygen.
Mr Caine also suggested that a key feature conferring novelty and inventive step, according to the applicants evidence, was the use of greater than 100% stoichiometric oxygen for combustion of fuel. This feature is not defined in the claims. He referred me to comments made by the declarants for the applicant in evidence in answer.
Ramus states in his declaration (Ramus #1) that he spent several weeks in April 1995 in Bolivia at a pilot plant operating the Minproc zinc fuming process which is the subject of the opposed specification. In clauses 12 and 13 Ramus states that the furnace at the Bolivian plant operated a submerged lance combustion system, where the lance was operating at a combustion stoichiometry of up to 110%. Ramus states that it was surprising to him that operating at a combustion stoichiometry of 110% still enabled the process to proceed at an oxygen partial pressure in the range 10-7 to 10-11 bar. His conclusion was that all of the oxygen was consumed by complete combustion of the fuel with the remaining oxygen being taken up by other reactions in the bath. At clause 22 Ramus states:
“In clause 30 at page 17, Rajakumar states that he understands and would have understood in 1989 "that the reducing gas phase described at page 14, lines 20 to 23 of the opposed patent application is equivalent to and certainly falls within the definition of the reductants described in 79186/87". The passage to which Rajakumar refers reads as follows, "The process condition required in the reactor itself is a reducing gas phase which can be achieved by providing approximately 90% of the stoichiometric air/oxygen for complete combustion of fuel and chemical reactions". I do not read this statement as meaning that only 90% of the necessary air/ oxygen for complete combustion of the fuel is added down the lance. I agree with Rajakumar that 90% of the air/oxygen required for complete combustion would mean that there was uncombusted fuel added to the bath as a reductant, however, the statement quoted refers to the stoichiometric requirement for complete combustion of fuel "and" chemical reaction. This amounts to significantly more than 100% of the air/oxygen required for complete combustion.”
And at 23:
“... Therefore the introduction to the bath through the lance of fuel plus 110% of the air/oxygen necessary for complete combustion of the fuel as taught by the opposed specification at page 14, lines 20-23 does not in my view, fall within the definition of reductant described in the CSIRO specification. I therefore do not agree that the fuel in the Minproc process acts as the reducing agent, nor are there any partial combustion products to provide reducing conditions. I see this as the principal distinguishing feature between the Minproc process and the disclosures of the CSIRO specification.”
I agree with Mr Ramus’ interpretation of the paragraph at page 14. However, according to Mr Caine, the claims do not teach the requirement found on page 14 lines 20 - 25. Further, according to Mr Caine, the requirement for greater than 100% combustion stoichiometry of oxygen refers to the Bolivian plant only and demonstrates the inadequacy of the claims and description.
Clause 28 of the Ramus declaration reads:
“I note that the sentence bridging pages 5 and 6 of the opposed specification states that the air/oxygen requirement is calculated on the basis of providing oxygen for combustion and for generation of a proportion of FeO, and I understand this to necessarily require the addition of more than 100% of the oxygen requirement for complete combustion of fuel.”
Mr Caine submitted that it was not tenable that greater than 100% combustion stoichiometry of oxygen was required before conversion of any FeS to FeO would occur. He directed me to the evidence in Rajakumar #3 which showed that even at low combustion stoichiometries, a proportion of FeO is generated from FeS.
Mr Caine then discussed the Kirby declaration. Kirby worked for Minproc Engineers and was sent to Bolivia to work on the zinc fumer plant. According to Kirby, the Bolivian plant operates the zinc fuming process which is the subject of the opposed application, although Mr Caine pointed out there was no precise description of the process worked in Bolivia. At clause 20 Kirby states that “the oxygen flow down the lance into the furnace was sufficient to supply the stoichiometric requirement for combustion of all of the fuel gas as well as the oxidation reactions in the bath. At all times a significant level of sulphur was maintained in the bath and the sulphur presence was thought to be critically important in maintaining the fuming process. During successful operation, the air flow down the lance was typically in the range 150 - 170 % of that required for complete combustion.” Mr Caine submitted that nowhere in the claims is there reference to an oxidation reaction. Mr Caine also drew a distinction between clause 29 of Kirby which states “a substantial part of the iron sulphide (FeS) in the feed of the process is oxidised in the bath to form iron oxide (FeO)” and the requirement of claim 1 that “a proportion of FeO is generated from the iron sulphide”. At clause 33 Kirby states that “sufficient sulphide is clearly an amount sufficient to control the partial pressure of oxygen in order to operate the Minproc Process which I accordingly understand to be any amount more than a vanishingly small amount”. As Mr Caine pointed out, the term “sufficient sulphide” appears in the description but not the claims.
At clause 40 Kirby states:
“From clause 30 of Rajakumar’s declaration it is clear to me that he has not fully understood the description of the Minproc Process specifically in the requirement for an oxidising gas stream to be injected down the lance and for oxidation reactions in the bath. A key part of the Minproc Process is the oxidation of a proportion of the sulphide in the feed with this oxidation supplying a part of the heat required for the overall process and with the proviso that sufficient sulphide is left in the bath to control the partial pressure of oxygen. In the Minproc Process the amount of oxygen going down the lance must be greater than the stoichiometric requirement for combustion of the fuel so that oxygen is available for oxidative reactions in the bath. This is quite different to the situation described in the CSIRO specification where insufficient oxygen for stoichiometric combustion is added so that reducing conditions prevail and oxidative reactions do not proceed in the bath.”
Mr Caine stated that this paragraph related to the Bolivian process rather than what was claimed or described. He pointed to a paragraph at page 14 of the opposed specification which states “The process condition required in the reactor itself is a reducing gas phase which can be achieved by providing approximately 90% of the stoichiometric air/oxygen for complete combustion of fuel and chemical reaction.” I have already indicated that I favour the applicant’s interpretation of this paragraph.
Mr Caine also discussed clause 22 of the Davey declaration. This clause reads as follows:
“Claim 1 of the opposed specification requires the presence of a liquid matte phase which contains at least iron sulphide and I have no difficulty in reconciling this statement in claim 1 with the reference in the description to the need to maintain sufficient sulphide in the bath. It is well accepted that any more than a vanishingly small amount of sulphide will be sufficient to control the partial pressure of oxygen since control is exercised not by the amount of sulphide present but by the mere fact that sulphide is present in more than a vanishingly small amount, ie a sufficient amount. The requirement that more than a vanishingly small amount is present is simply because in a practical process fluctuations in conditions over time could result in the disappearance of a small amount of matte phase, whereas it must be ensured that some matte phase is always present.”
Mr Caine argued that the claims did not require sufficient sulphide nor did they ensure it. He contrasted the requirement in the description for maintaining sufficient sulphide in the bath to control the partial pressure of oxygen with “contains at least iron sulphide” (claim 1); “including some iron oxide” (claim 13); “in conjunction with an iron sulphide” (claim 14); and “a molten bath containing iron sulphide” (claim 24). Mr Caine submitted that Ramus, Kirby and Davey had all identified a critical feature of the invention which was not present in the claims.
Mr Hess, for the applicant, stated that most of the opponent’s case rested on the declarations by Dr Rajakumar. But, according to Mr Hess, the evidence of Dr Rajakumar was unreliable. Mr Hess outlined several points which he said put doubt on the credibility of the Rajakumar declarations. Some of these points are relevant to the novelty issue so I will discuss them in some detail.
First, Rajakumar makes no reference to claim 1 of the CSIRO specification (PHH-1) when discussing that document. Claim 1 sets out the steps of the CSIRO process. The first step is adding the ore to a bath of molten matte that is “overlaid by a slag layer”. Then the bath is agitated and heated. Mr Hess submitted that the bath was underneath the slag layer ie there was no mixing of the matte and slag layers. This was followed by adding a reductant to the bath. Mr Caine countered this by saying that there is no requirement when comparing a disclosure to be bound by the narrowness of the claims. The relevant comparison is between the CSIRO application and the claims sought. I agree with Mr Caine on this point. But I think each of the steps is relevant to the discussion of novelty. I will consider them in detail later.
Mr Hess pointed out that Rajakumar compared the Minproc process with the CSIRO process at clauses 28 - 34. According to Mr Hess, each of the declarants for the applicant took issue with Rajakumar on this point. The declarants for the applicant stated that the CSIRO process was a process of reductive fuming, essentially a different process from the Minproc process. Mr Hess also stated that Rajakumar, at clause 54 of his second declaration, said that the other declarants had misunderstood the CSIRO process. Mr Hess pointed out that Davey, Ward and Ramus were totally independent of the applicant and the fact that Rajakumar said all the other experts were mistaken showed a lack of credibility of the Rajakumar declarations. Clause 54 reads:
“In paragraph 14 Whellock has incorrectly interpreted the CSIRO patent on two fundamental aspects. The CSIRO process is far from conventional slag technology. The CSIRO process does not take zinc into the slag phase followed by fuming out of the slag. The CSIRO patent teaches a single stage direct fuming process in which the zinc is fumed from the agitated bath. I fail to see the logic of this interpretation which Davey, Ward or Ramus or anyone else well versed in the field has made. Secondly Whellock has misunderstood the CSIRO patent as implying that there is a “separate” matte layer. The CSIRO system is also a well agitated system with intimate mixing of the slag and matte. It is clear that matte is formed in the opposed application as shown in the single example and the last sentence in paragraph 16 of Whellock.”
Mr Caine replied that Dr Rajakumar was one of the inventors of the CSIRO process and was well qualified to interpret it.
Mr Hess also took me to several paragraphs in the evidence where, he submitted, Rajakumar had conceded that the slag layer overlaid a separate matte phase. For example clause 28 of Rajakumar #2 states that the “CSIRO patent describes a process in which matte is overlain by a layer of slag and agitated.”
However Rajakumar says in a number of places that while the slag initially overlays the matte, agitation causes mixing of the phases. Clause 23 of Rajakumar #1 states ‘I note that claim 1 of the opposed patent application recites a matte phase which is intimately mixed in a bath with a slag phase.” At clause 28 Rajakumar states “I understand, and would have understood in 1989, that agitation by submerged injection of a fuel and air during the fuming process would be vigorous and result in the matte being intimately mixed in the bath with the slag phase.”
The latter point was addressed by the Ward declaration, in particular clauses 29 and 30 which read as follows:
“This contrasts with the situation in the process described in claim 1 of the CSIRO specification. This process consists of adding a sulphidic feed material to a bath of matte overlaid with a slag layer. The matte bath is agitated by the injection of a fuel and gas, reductant is added and the resultant fume is collected.”
“I understand by this description a process carried out in a bath in a manner similar to the converting of copper matte, ie a deep matte bath with a small amount of slag floating on the surface. The matte bath, while agitated, is not necessarily in intimate mixture with the slag phase in the sense that I have described above and there tends to be separation of the two liquid phases. ...”
Clause 28 of Rajakumar #2 states:
“The CSIRO patent describes a process in which matte is overlain by a layer of slag and agitated. During this agitation, the slag and matte are intimately mixed and Ward’s understanding in paragraph 34 that the slag layer stayed on top of the matte layer at the injection rates used is not a sensible construction. ... In point 35 Ward incorrectly assumes that a slag layer overlaying a matte layer remains as a separate layer in a well agitated bath and attempts to make an artificial distinction between the opposed application and the CSIRO patent.”
Clause 35 of Rajakumar #2 reads in part:
“... The CSIRO patent describes a process based on the addition of ore or concentrate to a bath of molten matte which is overlaid by a slag layer. When this bath is agitated, there is an intimate mixture of slag and matte. ...”
Mr Hess argued that there was no description in the CSIRO application of any intimate mixture of slag and matte. All that was described, as conceded by Rajakumar, was a separate matte layer.
Mr Hess also submitted that Rajakumar had shifted in his position between his first and second declarations. In clause 30 of his first declaration, Rajakumar said that the opposed process would not work without added reductant. The evidence of the applicant was against this. Rajakumar then said, for example at clause 10 of his second declaration, that he concludes that the alleged invention incorporates as an essential element the absence of any reductant. Mr Caine argued that any shift in the evidence of Dr Rajakumar was exclusively due to the lack of conformity between the description, claims and evidence as to the nature of the invention. This is supported to some extent by clause 3 of Rajakumar #2, where Rajakumar states that the applicant’s evidence more clearly highlighted the nature of the alleged invention to him and that several of the features of the invention highlighted in the applicant’s evidence did not appear in the claims.
Mr Hess also argued that the credibility of Rajakumar, at least as far as his first declaration is concerned, was damaged when he discussed the energy usage of the respective processes. At clause 33 Rajakumar states that the energy usage of the opposed application is similar to that of both the CSIRO and Davey and Turnbull documents. This was disputed by the applicant’s evidence, particularly clause 44 of Kirby and clause 24 of Ramus who claimed an energy savings of between 50 and 66% over the CSIRO application. Mr Hess said that Rajakumar was then silent on this point in his subsequent declarations.
There was also some argument between the parties over whether or not Dr Rajakumar was too qualified to be regarded as an addressee, as he was an inventor and high in the hierarchy of CSIRO. I am satisfied that Dr Rajakumar is qualified to give expert evidence in the present case. However I have been mindful of the facts that he is not independent of the opponent and that there has been some change in his understanding of the invention, at least as described, in light of the applicant’s evidence. I have taken these factors into account when reading his evidence.
Mr Hess submitted that the CSIRO document was not anticipatory. He said that the relevant tests are that the citation must contain “clear and unmistakable directions to carry out the present invention” and/or the citation must be an infringement of the claims of the opposed application. According to Mr Hess, the CSIRO process fails to recognise two important process conditions that are essential to the process of the opposed application.
The first process condition is that there must be in the bath an intimate mixing of the liquid matte and the slag. Mr Hess claimed the requirement for intimate mixing is not taught by the CSIRO document. Mr Hess submitted that agitation per se does not achieve the necessary intimate mixing of the inventive process. As discussed above, the applicant claimed that in the CSIRO document, the slag layer is separate to, and overlays, the liquid matte.
The second process condition is that there must be sufficient iron sulphide in the bath so that a proportion of FeO is generated from the iron sulphide of the mixture.
Mr Hess stated that all of the claims required the bath to contain iron sulphide. The only question is whether or not that is enough for sufficient iron sulphide. (The description states that it is important to maintain sufficient sulphide in the bath to control the partial pressure of oxygen (page 3c line 13) and that adequate sulphide is present in the bath to avoid oxidising conditions (page 5 line 20)). Mr Hess submitted that the applicant’s evidence showed that as long as there was not a vanishingly small amount of sulphide in the bath this condition was met. In particular, Mr Hess directed me to clause 22 of Davey, which I have set out earlier, and clause 33 of Kirby which states:
“... However sufficient sulphide is clearly an amount sufficient to control the partial pressure of oxygen in order to operate the Minproc Process which I accordingly understand to be any amount more than a vanishingly small amount.”
I note here that Kirby refers to the term “sufficient sulphide” used in the description rather than the terminology used in the claims.
Mr Hess submitted that the consequence was that the inventive process works differently to the CSIRO process and with considerable energy savings. He stated that the process of the opposed application is a one step process which occurs with an intimately mixed liquid matte and slag in the bath. With the addition of energy, there is an oxidation reaction of FeS to FeO, as long as some iron sulphide is present. This reaction controls the oxygen partial pressure at the reaction temperature. By contrast, according to Mr Hess, the process described by the CSIRO document effectively is a two stage reactive process of oxidation and reduction. First, in the oxidation reaction, ZnS in the matte is moved into the slag as ZnO. Then, in the reduction reaction, the ZnO in the slag is reacted with a carboniferous reductant to form zinc plus reaction products in the fume. Mr Hess stated that at page 9 line 18 of the CSIRO application the process is described as “... essentially a reductive fuming operation ...”. He submitted that reduction fuming of zinc from the slag is well known. This point is addressed at clause 54 of Rajakumar #2, which I have also set out earlier.
Mr Hess also made submissions on the Davey and Turnbull paper (PHH-2). He pointed out that Davey and Turnbull was a theoretical paper which contains no reference at all to the importance of iron sulphide to the process of the opposed application. Further there is no reference to the process requirement of the intimate mixing of the liquid matte and slag. This is supported by the applicant’s evidence, particularly the Davey declaration. Davey states at clause 20 that “it is incorrect to say that the Davey and Turnbull paper co-authored by me discloses any particular apparatus or the need to operate the process in an agitated matte/slag bath. Such a statement reads into the Davey and Turnbull paper issues not discussed in the paper.” Mr Hess also stated that oxygen partial pressures are not mentioned at all in this paper.
The parties also made submissions on a number of other points, which I will consider further at the relevant points.
Anticipation
I will now consider the above points in relation to the particular documents cited by the opponent, particularly the CSIRO specification and the Davey and Turnbull paper.
CSIRO Application 79186/87
The CSIRO application relates to a process for the treatment of lead-zinc complex sulphide ores and concentrates. The described process simultaneously recovers lead and zinc as a fume using a bath smelting process in which the contents are vigorously agitated by the injection of gas. In carrying out the smelting reactions a high-iron matte is produced. The temperature of the operation is typically 1350 - 1400 °C. The process operates at an oxygen potential of approximately 10-9 atmosphere. This is equivalent to the partial pressure of oxygen and equates to approximately 10-9 bar. The specification describes a number of examples where sulphide concentrates containing significant amounts of iron are used as the feed. The specification recites injecting fuel and air into the bath to agitate and heat the bath. Rajakumar states that the injection of fuel and air would result in combustion products which form a gas phase and act to carry the zinc vapour from the bath.
It appears to be common ground between the declarants for the parties that in a matte fuming process for zinc from sulphide concentrates it is the oxygen potential at the operating temperature that determines whether or not zinc is fumed. Both the opposed application and the CSIRO specification disclose similar oxygen potentials and operating temperatures. However, the applicant contends that the Minproc process and the CSIRO process are fundamentally different in the way in which they achieve the oxygen potential. According to the applicant, the Minproc process depends upon maintaining sufficient sulfide in the bath to control the partial pressure of oxygen. By contrast, the CSIRO process depends upon adding a reductant to the bath.
I am satisfied that a process whereby the partial pressure of oxygen is controlled by using an excess of the stoichiometric amount of oxygen for complete combustion of fuel so that a proportion of FeS is converted to FeO with the proviso that sufficient sulphide is maintained in the bath to control the partial pressure of oxygen is inventive over the CSIRO process. This is the process described in the preferred embodiment of the opposed application and referred to in evidence by the applicant’s declarants. However I am not satisfied that the claims are limited to this process.
The claims require that a proportion of FeO is generated from the iron sulphide. As stated above, Mr Hess argued that this was adequate definition to encompass the bath having sufficient sulphide to control the partial pressure of oxygen and all that was needed was any more than a vanishingly small amount. Davey at clause 22 states that “ Claim 1 of the opposed specification requires the presence of a liquid matte phase which contains at least iron sulphide and I have no difficulty in reconciling this statement in claim 1 with the reference in the description to the need to maintain sufficient sulphide in the bath.” However, this appears to be reading too much into the claims. Many zinc sulphide feeds include iron sulphide, including those disclosed in the CSIRO specification. I do not think that the mere presence of iron sulphide in the matte ensures that the iron sulphide controls the partial pressure of oxygen. It is clear from the description and evidence that conversion of iron sulphide to iron oxide can serve a number of useful purposes. The claims do not clearly specify that this is the mechanism whereby the partial pressure of oxygen is controlled.
At clause 40, which I have set out in full earlier, Kirby states that a “key part of the Minproc Process is the oxidation of a proportion of the sulphide in the feed with this oxidation supplying a part of the heat required for the overall process and with the proviso that sufficient sulphide is left in the bath to control the partial pressure of oxygen” (emphasis added). I also note that clause 8 of Kirby #2 states, in reference to the CSIRO specification, that “I find ... no appreciation of the fact that only a proportion of FeS should be converted to FeO so that sufficient sulphide is maintained in the bath to control the partial pressure of oxygen” (emphasis added). Also, the description of the opposed application at page 3c states that “it is possible to oxidize a proportion of the iron sulphide that is present either through oxygen or air from combustion or from other oxidic materials in the charge. However, it is important to maintain sufficient sulphide in the bath to control the partial pressure of oxygen...” (emphasis added). Both the specification and Kirby state that while it is necessary to convert a proportion of iron sulphide to iron oxide, there is a proviso that sufficient sulphide is maintained in the bath to control the partial pressure of oxygen. While the conversion of a proportion of iron sulphide is defined in the claims, there is no clear and unambiguous definition of the proviso of maintaining sufficient sulphide in the claims.
Mr Caine said that the conversion of a proportion of FeO from iron sulphide was an inevitable consequence of the CSIRO process rather than a direct disclosure. He directed me to Nicaro Holdings v Martin Engineering 91 ALR 513, where Gummow J at 529 quoted from General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 at 485-6 (emphasis added):
“The prior inventor, however, and the patentee may have approached the same device from different starting points and may, for this reason, or it may be for other reasons, have so described their devices that it cannot be immediately discerned from a reading of the language which they have respectively used that they have discovered in truth the same device; but if carrying out the directions contained in the prior inventor’s publication will inevitably result in something being made or done which, if the patentee’s patent were valid, would constitute an infringement of the patentee’s claim, this circumstance demonstrates that the patentee’s claim has in fact been anticipated.”
Mr Caine also directed me to Merck & Co, Inc v Sankyo Co Ltd 23 IPR 415, where it was held that if a substance is inevitably produced by following the reactions described in an application then that application does not disclose new matter even when that substance has been misidentified in the application. Mr Caine said that while this case was in relation to allowability of amendments, the sentiment regarding inevitable consequence is broadly supportive in the context of novelty.
Rajakumar states in his third declaration that a proportion of FeO is generated from iron sulphide in all zinc matte fuming processes including the CSIRO process. He states that FeS and FeO form liquid solutions in virtually all combinations and exhibited a copy of the FeS-FeO binary phase diagram in evidence[1]. At clause 9 Rajakumar states that he carried out a simple evaluation of the thermodynamics of the CSIRO process. He states:
[1] Fig. 27, page 43, “Slag Atlas”, Verlag Stahl Eisen mbH, Dusseldorf 1981, exhibited as VR-4
“At an air supply corresponding to a “low” 65% combustion stoichiometry, a proportion of the iron sulphide in the concentrate is converted to iron oxide to give a matte phase containing about 7% dissolved FeO and slag is not formed. At 80% combustion stoichiometry, the matte can contain about 12% dissolved FeO and there is no slag formation. At 95% combustion stoichiometry, matte and slag are produced with the slag in equilibrium with matte which contains about 17.9% FeO.”
The examples where there is no slag formation are not relevant to the claims as the claims require slag as a necessary feature. But Rajakumar goes on to say that the evaluation shows that “even at low combustion stoichiometries corresponding to the formation of matte with low slag fall, ..., a proportion of FeO is generated from iron sulphide. When the combustion stoichiometry is progressively increased, increasing proportions of the iron sulphide are converted to iron oxide until, at a critical stoichiometry, matte saturated with FeO coexists with slag”. It is logical that the more oxygen there is available, the more it will react with iron sulphide.
Kirby states in the evidence in response that without further details of Rajakumar’s thermodynamics evaluation, he cannot comment on the validity of his conclusions. He states that in any case, the CSIRO specification does not foreshadow the role played by the conversion of a proportion of FeS to FeO in controlling the partial pressure of oxygen. As I have stated already, this is not clearly enunciated in the claims. Kirby also states that it is by no means clear to him that at low combustion stoichiometries a proportion of FeO is necessarily generated.
I note that in the examples of the CSIRO specification there are minor amounts of slag produced which cannot be completely separated from the matte. At Kirby #2, clauses 9 and 10, Kirby states the role of the conversion of FeS to FeO is not discussed in the CSIRO specification. This distinction is directed more to what is described than what is claimed. It appears to me that even at sub-stoichiometric combustion, as described in the CSIRO specification, some oxygen will react with a proportion of the iron sulphide to generate FeO. Rajakumar’s evidence supports this conclusion. I also note that clause 32 of Ward infers the presence of ferrous oxide in the CSIRO process, as Ward states that in some of the examples of the CSIRO process slag may not have been formed because of the known solubility of small amounts of ferrous oxide in mattes. I am satisfied that the conversion of a proportion of iron sulphide to FeO is an inevitable consequence of the CSIRO specification and is thereby disclosed. While the role played by the conversion of iron sulphide to FeO is not foreshadowed by the citation, the claims are not so limited.
The other question to be answered is whether or not the CSIRO specification discloses the intimate mixing of the slag and matte phases. The CSIRO specification describes vigorously agitating the bath by the injection of gas. This is done by means of one or more submerged lances through which fuel and air are introduced. The preferred method of providing intimate mixing in the opposed application is by injecting a combustion mixture, eg natural gas and oxygen enriched air, through a submerged lance to impart a high degree of agitation. Therefore both processes provide vigorous agitation by similar means. The applicant contended that in the CSIRO process, only the matte bath is agitated and not the slag.
Ward gives a good explanation of the role of intimate mixing and the mechanisms involved in the Minproc process in his declaration. He states that the active bath in the process, comprising a mixture of gas, matte and slag phases is necessarily well mixed. This allows the phases to approach equilibrium. In the CSIRO process, according to Ward, the equilibrium is essentially between the gas and matte phases. The sulphur pressure is determined by the matte properties at the reaction temperature. However as there is no slag or oxide phase, as in the Minproc process, the oxygen pressure must be fixed externally to the system by the addition of a reducing agent. Ward states that he understands the CSIRO process to be carried out in a bath in a similar manner to the converting of copper matte, ie a deep matte bath with a small amount of slag floating on the surface. This contrasts with the case where the more viscous slag phase is the continuous phase.
However I am not satisfied that the claims of the opposed application clearly set out the features which distinguish the described invention from the CSIRO process. The claims do not define any particular amount of slag or define it as being a continuous phase. Nor do the claims define the conditions which would produce such a system eg a combustion stoichiometry of greater than 100% so that a proportion of iron sulphide is oxidized and sufficient sulphide is maintained in the bath to control the partial pressure of oxygen. The claims merely require that some slag be present and that it be intimately mixed with the matte phase.
Example 1 of the CSIRO specification states that slag formation was negligibly small and the slag could not be separated from the final matte. Example 2 states that 0.26 kg of matte and 0.014 kg of slag are formed per kg of wet feed. Example 5 states that a matte was produced with a minor amount of slag which could not be completely separated. It appears from these examples that the small amounts of slag formed are mixed with the matte by the injection of air into the bath through submerged lances.
The example in the opposed application states that 240 kg of slag and 160 kg of matte are produced per 1000 kg of wet feed. I have already noted that the claims place no limitation on the amount of slag present. The description at page 10 of the opposed application states:
“The presence of a liquid matte containing iron sulphide is essential to control and limit the accumulation of zinc oxide in the slag phase. At the matte-slag interface, the oxygen potential is set by the compositions of the two liquid phases and remains relatively constant during the progress of smelting as long as both matte and slag phases are present.”
At least some of the examples of the CSIRO specification describe systems where both matte and slag are present. The CSIRO specification also describes agitating the bath in a similar manner to that described in the opposed application. It appears from the evidence that the features distinguishing the Minproc process from the CSIRO process is the provision of a combustion stoichiometry of greater than 100% so that a proportion of iron sulphide is oxidized and sufficient sulphide is maintained in the bath to control the partial pressure of oxygen. As I have stated, these features, while described in the preferred embodiment of the invention, are not defined in the claims.
It was also put forward in the applicant’s evidence that the CSIRO specification was directed to lead-zinc concentrates only. However, page 16 of the opposed application states that another application of the process is the treatment of zinc-lead feed materials containing iron. Therefore the feed materials described in the CSIRO application are clearly within the scope of the claims of the opposed application.
I therefore find independent claims 1, 14 and 24 to be anticipated by the CSIRO specification.
The claims dependent on claims 1, 14 and 24 generally relate to the preferred operating conditions, feed materials and after-treatment of the fumed zinc. The opponent contended that each of these claims was not novel or obvious in light of the prior art. A number of these claims are directly disclosed by the CSIRO specification. The opponent argued that the others merely recite features of smelting and fuming processes which are well known to skilled workers in Australia.
There is limited evidence on the dependent claims apart from some consideration given to them in Rajakumar #1. Rajakumar states at clause 11 that he was familiar with all the patent specifications exhibited in the declaration of Peter Harold Huntsman and that they formed part of his general knowledge. He states that he believes it is common practice to keep up to date with the literature, including watching journal articles and reading all new patent applications as they are published. At clause 38 Rajakumar also refers to processing conditions which he states are well known to him and to other skilled workers in Australia. Mr Hess argued that the opponent had not provided any evidence as to the knowledge of the ordinary worker in the art. I agree with Mr Hess that the fact that Dr Rajakumar, or anyone else, reads all new patent applications does not establish that these patent applications are part of the common general knowledge. Rajakumar’s evidence in his first declaration in relation to the dependent claims also appears to suffer from his misunderstanding that the invention, even as described, would not work without the addition of a reductant.
Despite the limited usefulness of the evidence in relation to the dependent claims, the dependent claims do not appear to add any features which would materially affect the working of the invention. None of the dependent claims add the feature of controlling the partial pressure of oxygen by maintaining sufficient sulphide in the bath. In my view, none of the dependent claims add an inventive step over the CSIRO application
The opponent conceded that claim 13 was novel over the CSIRO specification, but argued that it lacked an inventive step. Claim 13 defines a method in which the reaction occurs in the freeboard of the furnace rather than in the bath. With the addition of air and/or oxygen in sub-stoichiometric ratio, a proportion of FeO is generated from iron sulphide included in the feed. The opponent contended that the term “sub-stoichiometric ratio” meant that there was less than 100% combustion stoichiometry of air and therefore a proportion of the fuel is performing the function of reducing agent. However the term “sub-stoichiometric” is used in the claim in relation to the partial oxidation of iron sulphide and appears to be referring to the overall stoichiometry rather than the combustion stoichiometry. This is consistent with the description. The CSIRO process is only concerned with bath reactions. There is nothing in the citation which would suggest to a skilled addressee to adopt the process to a freeboard reaction, using a sub-stoichiometric amount of oxygen to partially oxidize a proportion of iron sulphide.
Claim 13 is novel and inventive over the CSIRO specification.
Davey and Turnbull paper
The Davey and Turnbull paper was the result of a theoretical analysis of the direct smelting of zinc sulfide concentrates carried out using computer simulation techniques involving computer based thermodynamic equilibrium calculations. The Davey and Turnbull paper initially considers pure systems containing only ZnS and C and air then covers practical systems using a typical zinc sulphide concentrate (concentrate c1) and a zinc-lead-copper concentrate (concentrate c2). The calculations for concentrate c1 allowed for an oxide slag as a possible product while for concentrate c2 the possible formation of slag, matte and alloy phases was considered. All of the declarants for the applicant emphasised that the Davey and Turnbull paper discussed a theoretical process based on calculations and certain assumptions and does not disclose the operating conditions necessary for a practical operating process.
Rajakumar states at clause 27 of Rajakumar #1 that while the oxygen partial pressure cannot directly be found in the paper, he understands from the inclusion of “an adaptation of the well known Yazawa diagram” that the oxygen partial pressure would have been of the order of 10-9 bar. He also states that vigorous agitation of the bath would be required to achieve an intimate mix of the slag and matte in order to obtain equilibrium between the slag, matte and gas phases. Rajakumar also states that the Davey and Turnbull reference discloses the use of coal and air. He states that the reaction between coal and air would produce gaseous combustion products which would have the effect of transporting the fumed vapour from the bath. At clause 40 of his second declaration, Rajakumar states that “Davey’s example is easily understood to be very oxidising so that very little if any matte was formed. It was common knowledge prior to 1990 that partial oxidation of the FeS and FeO can be allowed for such that a desired amount of matte is formed.” Rajakumar also states that he would have understood these things in 1989.
Dr Rajakumar has identified a number of features which are not directly disclosed by Davey and Turnbull. He has stated that these features would have been common knowledge in 1989 ie before the priority date of the opposed application. However the opponent has filed no evidence as to the state of common general knowledge at the publication date of Davey and Turnbull. As Davey and Turnbull contains no disclosure of several of the operating conditions included in the claims, it cannot be said that it contains clear and unmistakable directions to do what has been claimed. I am satisfied the claims are novel over Davey and Turnbull.
The opponent also argued that the claims lack an inventive step over Davey and Turnbull. Rajakumar, at clause 58 of Rajakumar #2, refers to the problem outlined in the Whellock declaration. I have outlined this above under the heading “Evidence”. Rajakumar states that given this problem it is within the skill of a person having experience in the field to provide appropriate conditions for fuming without the need for excess quantities of coal or carbon. Rajakumar states that using the computer simulation package Metsim, the use of an excess of oxygen to provide for the formation of iron oxide from iron sulphide to provide conditions for the fuming of zinc was readily able to be achieved. As stated above, Rajakumar also argued, for example at clause 27 of Rajakumar #1, that he believes a number of features were common knowledge.
At clauses 51 and 52 Ward makes the following comments about the Davey and Turnbull paper:
“... The paper makes no mention of the fact that the process should be carried out in a molten bath in which a matte phase containing iron sulphide should be an intimate mixture with a slag phase as taught by the opposed specification. On the contrary the indications are that a flash smelting process was envisaged although this is not clearly stated.”
I accordingly consider that the comments made in clause 27 can only be made with the benefit of hindsight. Knowing from the opposed specification that a bath sulphidization process is feasible it then becomes an academic exercise to show that the chemistry described by Davey and Turnbull applies to it since thermodynamics is only concerned with the outcome of a chemical reaction equilibrium not the method of achieving it. I do not consider that the reverse reasoning applies, ie that the slag/matte bath process is obvious because it obeys a thermodynamic equilibrium. The Davey and Turnbull Paper makes no reference to carrying out their process in a molten bath. I believe the few hints given in the paper suggest that they may have had a flash smelting process in mind and matte is mentioned only as a necessary product of copper smelting. Accordingly I consider the final subparagraph of paragraph 27 of the Rajakumar declaration can be substantiated only in hindsight simply because Davey and Turnbull were only describing the process chemistry and made no mention of a bath process. They do not identify a key requirement of claim 1 of the opposed specification namely that an iron rich matte phase in intimate mixture with the slag phase is a process necessity.”
Davey also states that the Davey and Turnbull paper did not teach nor advocate the deliberate formation of a matte phase, nor contemplate its use to control the oxygen partial pressure, nor the function of iron sulphide to lessen the amount of fuel required for the process.
Kirby at clauses 27 and 37 refers to exhibit PHH-15[2] filed in evidence by the opponent. In the introduction, the authors of this paper refer to the Davey and Turnbull paper as a theoretical calculation of direct smelting and state that no report has been published on the experimental testing of these processes as far as it is known. The authors conclude that “In the light of the evidence in the literature it may be difficult to produce zinc directly from the zinc concentrates in a single process.” The authors go on to consider a two stage process.
[2] Gupta SK & Floyd JM “Direct Smelting of Zinc” DGM Conference, Cologne, 1989, 16pp.
I tend to agree with the applicants evidence regarding the Davey and Turnbull paper. While the paper may have provided useful background information, there were still practical difficulties to be overcome in developing a process that would operate in practice. While it may have been possible to use a computer program to show that fuming with an excess of oxygen was feasible, it does not follow that using a slag/matte bath under the claimed conditions was obvious. I find that the claims are inventive over the Davey and Turnbull paper.
Section 40
The opponent alleges in the statement of grounds and particulars that the complete specification does not comply with section 40. The opponent set out a number of points in the particulars. Many of these points have been dealt with by the amendments subsequently filed by the applicant.
The opponent alleges that claim 13 does not define the invention because it makes no reference to the essential feature of an intimate mixture of molten matte with a slag phase in the bath. Claim 13 defines an alternative process route utilising reactions in the freeboard rather than in the bath. There is a consistory statement at page 3a corresponding to claim 13. The alternative route utilising flash reactions in the freeboard is also described at pages 6 and 7. Rajakumar also states at clause 53 that he considers the claim extremely ambiguous because it recites that a zinc oxide or zinc sulphide bearing material and including some iron sulphide is partially oxidized in the freeboard of a furnace. I do not see any difficulties with this and the claim is supported by the description at pages 3a and 6 and 7.
The opponent also states that claim 25 is unclear because it defines an oxygen partial pressure of
10-9 bar but is appended to claim 24 which defines the partial pressure at 10-8 bar. I agree with the opponent that claim 25 is unclear as it is in conflict with claim 24.
The opponent also states that the specification does not describe the invention fully as the example does not give sufficient details to perform the invention and there is no indication of the level of sulphide to be maintained in the bath. I do not believe the opponent has established that the specification lacks sufficiency. The applicant’s evidence is that the need to maintain sufficient sulphide as described in the specification is linked to the requirement to control the partial pressure of oxygen and could be any amount more than a vanishingly small amount.
There were a number of section 40 points raised in evidence that were not particularised. Mr Hess submitted that I should give no consideration to these. However the applicant has had sufficient opportunity to address these issues and has done so in their evidence.
Rajakumar at clauses 19 and 25 states that the invention requires the input of energy but the claims are silent on this. The claims require the process to operate at a temperature of 1250 to 1400 °C. I agree with the evidence of Kirby and Ramus that if an endothermic reaction is to be carried out within a given temperature range, the need for an input of energy is implicit. I see no need for the claims to explicitly include the input of energy.
Rajakumar also suggests that it is necessary for the claims to define an agitated matte/slag system as well as having the matte intimately mixed in the bath with the slag phase. Kirby, Ramus and Ward all state that it is the intimate mixing of the slag and matte phases which is essential to the invention. The agitation of the bath is the preferred example of how the intimate mixing may be achieved. This appears to be consistent with the description of the invention.
The opponent also argued that the claims fail section 40 because they do not define the requirement to maintain sufficient sulphide in the bath to control the partial pressure of oxygen. There is some merit in this argument. I have dealt with this in some detail already in discussing the novelty of the claims. The declarants for the applicant all identify this as the key distinguishing feature of the invention. I consider the claims do not define the invention as they do not define this requirement. However I think the applicant could amend the claims in a number of ways to overcome this deficiency and the lack of novelty. For example, they could include the requirement of providing approximately 90% of the stoichiometric air/oxygen for complete combustion of fuel and chemical reaction so that a proportion of FeO is generated from iron sulphide, as set out at page 14. Alternatively, they could include the requirement that a proportion of FeO is generated from iron sulphide while maintaining sufficient sulphide in the bath to control the partial pressure of oxygen as described at page 3c. One appears to be the result of the other. In my opinion either of these amendments would distinguish the claims from the CSIRO specification and would be fairly based on the description. There may also be other ways of amending the claims open to the applicant. I do not think I should unnecessarily restrict the applicant by requiring them to amend the claims in a particular way.
costs
The parties requested at the hearing that they be given time to file submissions on costs when the reasons for the decision issued, given that the specification was amended late in proceedings. I agreed to this request. I give the parties 21 days from the date of this decision to file submissions on costs.
conclusion
I have found that claims 1 to 12 and 14 to 26 lack novelty and/or inventive step over patent application 79186/87 by CSIRO. I have also found that the claims ddo not comply with section 40 as they do not define the invention. Further, claim 25 in unclear as it is in conflict with claim 24, to which it is appended. However there is patentable subject matter in the specification. I allow the applicant 60 days from the date of this decision to file amendments overcoming the objections set out herein.
Brendan Bourke
Delegate of the Commissioner of Patents
Patent attorneys for the applicant : Oberins Arthur Robinson & Hedderwicks, Melbourne
Patent attorneys for the opponent : Davies Collison Cave, Melbourne
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