BHP Billiton Worsley Pty Ltd v Alcoa of Australia Pty Ltd
[2014] APO 30
•20 May 2014
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
BHP Billiton Worsley Pty Ltd v Alcoa of Australia Pty Ltd [2014] APO 30
Patent Application: 2004224944
Title:Method for Causticisation of Alkaline Solutions
Patent Applicant: Alcoa of Australia Pty Ltd
Opponent: BHP Billiton Worsley Pty Ltd
Delegate: Karen Ayers
Decision Date: 20 May 2014
Hearing Date: 3 April 2014, in Canberra
Catchwords: PATENTS – opposed on the basis of clarity, utility, novelty and inventive step – claims unclear due to ambiguity – applicant’s preferred construction resolves clarity and utility concerns – long standing practice in the industry used lower temperatures and longer residence times – skilled worker had recognised that high temperatures would increase reaction rate but not the advantage of a particularly short residence time – this combination had benefits not envisaged in the prior art – claims were therefore novel and inventive
Representation: Patent applicant: Julian Cooke of counsel instructed by Dr Brendan Peachey patent attorney from Wrays, Perth. Dr Charmaine de Witt and Mr Shannon Dye were also in attendance on behalf of the applicant company
Opponent: Andrew Fox of counsel instructed by Dr Marguerite Port patent attorney from McCarthy Port Patent and Trade Mark Attorneys, Perth
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Patent Application: 2004224944
Title:Method for Causticisation of Alkaline Solutions
Patent Applicant: Alcoa of Australia Pty Ltd
Date of Decision: 20 May 2014
DECISION
The opposition is partly successful. Claim 1 with regard to the term ‘residence time’ is ambiguous and therefore lacks clarity. Based on the applicant’s preferred construction, the claims are however clear and useful. None of the citations provided by the opponent deprive any of the claims of their novelty of inventive step.
The specification contains patentable subject matter. I allow the applicant 2 months from the date of this decision to propose amendments to overcome the deficiencies noted above in this decision.
Costs are awarded against the applicant.
REASONS FOR DECISION
Background
Patent application 2004224944 was filed on 1 November 2004 by Alcoa of Australia Pty Ltd as a divisional application of 39473/00 (2000039473). The parent application had been filed on 20 April 2000 under the provisions of the PCT claiming priority from an Australian provisional application (PP 9982) filed on 23 April 1999.
The parent has lapsed under the provisions of section 142(2)(e) (failure to gain acceptance within the prescribed time). The divisional application was advertised as accepted on 31 July 2008 and a notice of opposition was filed on 30 October 2008 by BHP Billiton Worsley Pty Ltd. Evidence (including 2 rounds of further evidence) was completed on 10 June 2013 and the matter set for hearing in Canberra on 3 April 2014.
Evidence
The following evidence was filed in this opposition:
(a)Evidence in support
Statutory declarations by:
(i)Expert evidence
Lyndon George Armstrong dated 28 January 2009 (together with exhibits LA-1to LA-2) (Armstrong#1)
(ii)Publication evidence
Janine Lois Krochmal dated 26 October 2009
Tracey Murray dated 29 October 2009
Helen Owens dated 29 October 2009
Iwan Hiralal dated 2 December 2009 (together with exhibit IH-1)
Ngaire Pettit-Young dated 9 December 2009
Mary Louise Turonek dated 22 December 2009 (together with exhibits MLT-1 to MLT-18)
(b)Evidence in Answer
Gregory Power dated 30 March 2011 (together with exhibits GPP-1 to GPP-2) (Power#1)
(c)Evidence in Reply
Lyndon George Armstrong dated 5 December 2011 (together with exhibits LA-3 to LA-5) (Armstrong#2)
Lyndon George Armstrong dated 25 March 2012 (together with exhibits LA-6) (Armstrong#3)
Lyndon George Armstrong dated 12 April 2012 (Armstrong#4)
(d)Further evidence - round 1 (applicant)
Gregory Power dated 6 August 2012 (together with exhibits GPP-1 to GPP-2) (Power#2)
Gregory Power dated 6 September 2012 (together with exhibits GPP-1 to GPP-2) (Power#3)
Gregory Power dated 6 September 2012 (together with exhibits GPP-1 to GPP-2) (Power#4)
(e)Further evidence in response – round 1 (opponent)
Lyndon George Armstrong dated 17 March 2013 (together with exhibits LA-7- to LA-8) (Armstrong#5)
Silvio Nicoli (together with exhibits SN-1 to SN-2)
(f)Further evidence– round 2 (applicant)
Gregory Power dated 12 April 2013 (Power#5)
Gregory Power dated 12 April 2013 (Power#6)
(g)Further evidence in response – round 2 (opponent)
Silvio Nicoli dated 22 May 2013 (Nicoli#2)
Lyndon George Armstrong dated 1 June 2013 (together with exhibits LA-7- to LA-8) (Armstrong#6)
Onus of Proof
The examination request for the current patent application was filed on 27 March 2009. As a consequence, substantive amendments of the Patents Act brought about by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 do not apply to the present application. This includes the amendment to subsection 60 (3A) that allows the Commissioner to refuse a patent application if satisfied on the balance of probabilities that a ground of opposition exists.
Consequently the former standard for opposition proceedings applies and the opponent must establish that it is clear or practically certain that the patent is invalid (F Hoffman La Roche AG v New England Biolabs Inc [2000] FCA 283 at [29], [67]; 50 IPR 305 at 311, 319; Commissioner of Patents v Sherman [2008] FCAFC 182 at [18], [22]; 79 IPR 426; Genetics Institute Inc v Kirin-Amgen Inc [1999] 92 FCR 106 at [17]).
Technical Background to the invention
Bauxite contains 30-54% alumina [aluminium oxide (Al2O3)] with the remainder of the ore composed of various iron oxides, titanium oxide and some organic material[1]. Alumina needs to be purified from bauxite before it can be used in aluminium manufacture. This purification is achieved using the ‘Bayer process’, a process which has four basic steps[2]:
[1] Armstrong#1 at [3.4]
[2] Steps are summarised by Armstrong#1 at [3.4]-[3.18] and Power# at [37]-[68].
1. ‘Digestion’: bauxite is mixed with a hot solution of sodium hydroxide (caustic soda solution) in “digester” vessels operating at high pressure in the temperature range of 150-280oC. This step converts alumina to soluble aluminium hydroxide.
2. ‘Clarification’: the reaction mixture from the previous step is transferred to “thickening tanks” so that the insoluble components can be settled out of the aluminium hydroxide-rich solution. The resulting (‘clarified’) solution is referred to as ‘pregnant liquor’.
3. ‘Precipitation’: the pregnant liquor is seeded with aluminium hydroxide to precipitate aluminium hydroxide crystals which are recovered by filtration. The remaining filtrate is referred to as ‘spent liquor’.
4. ‘Calcination’: the solid (aluminium hydroxide) precipitate is washed and heated to temperatures in excess of 1000oC to decompose the aluminium hydroxide to alumina which can then be used as feedstock in aluminium smelting.
Although precipitated aluminium hydroxide is recovered during the Precipitation stage, the spent liquor still contains a relative high concentration of dissolved aluminium hydroxide and caustic soda. Rather than discard this material, it is therefore recycled back into Digestion. However, the spent liquor also contains significant amounts of sodium carbonate produced by the reaction of sodium hydroxide with organic carbonates (from the bauxite) in the digestion stage:
Sodium hydroxide + carbonate → sodium carbonate + water (equation 1)
Sodium carbonate (Na2CO3) depletes the recycled solution of sodium hydroxide needed for digestion. Hence the recycled solution also undergoes a process known as ‘causticisation’ which uses lime to chemically convert the sodium carbonate to sodium hydroxide. The causticisation reaction is as follows:
Sodium carbonate + lime → sodium hydroxide + calcium carbonate (equation 2)
Lime can be added as either calcium oxide (“quicklime” or dry lime”) or calcium hydroxide (“slaked lime”). Slaked lime is formed by the addition of quicklime to water as follows:
Calcium oxide + water → calcium hydroxide (equation 3)
10.The conversion of quicklime to slaked lime is an extremely exothermic reaction and if quicklime is added to the liquor, the slaking step (equation 3) will precede the causticisation reaction (equation 2). This means causticisation process is only exothermic (generates heat) if quicklime is used.
11.Hall introduced the causticisation reaction into the Bayer process in around 1900. At that time until at least the 1950s, the reaction was mostly conducted in situ during digestion (‘inside causticisation’). By the 1970s, the alumina industry began causticising Bayer liquors as a side stream process prior to redirection of the causticised liquor back to the Bayer circuit downstream. This process is known as ‘outside causticisation’.
12.Notwithstanding its widespread use in the Bayer process, the causticisation reaction presents well known difficulties in practice. In particular, there are a number of competing chemical reactions in the causticisation process resulting from the presence of aluminate ions in the mixture. One of these competing reactions produces the undesirable by-product tricalcium aluminate (also known as TCA):
Calcium hydroxide + sodium aluminate → tricalcium aluminate (TCA) + sodium hydroxide (equation 4)
13.Insoluble TCA is a particular problem because it contributes to the alkalinity of insoluble waste from the Bayer process which impacts the environment[3]. TCA also consumes more lime[4] and alumina and hence it lowers the efficiency (increasing the cost) of the overall process[5].
[3] Opposed specification page 3, lines 8-11
[4] It consumes 3 moles of lime for each mole of TCA produced (equivalent to the loss of 6 moles of NaOH – see Armstrong#1 at [3.21]
[5] Power#1 at [62]
14.There are two separate ways of measuring the efficiency of the causticisation reaction known as ‘causticisation efficiency’ and ‘lime efficiency’. ‘Causticisation efficiency’ is a measure of the amount of carbonate removed from the solution (increasing the levels of NaOH present). It is expressed as the ratio TC/TA (also known as C/S) where ‘TC’ is amount of sodium hydroxide in the liquor (total caustic) and ‘TA’ is the amount of sodium hydroxide and sodium carbonate (total alkali)[6]. A high TC/TA (approaching the maximum of 1) is desirable because this means high levels of sodium hydroxide.
[6] Both TC and TA concentrations are expressed in terms of gL-1 sodium carbonate.
15.‘Lime efficiency’ is the proportion (expressed as a percentage) of total CaO used to form calcium carbonate (rather than being used elsewhere in competing side reactions). A high percentage is desirable because it means more calcium carbonate (and less TCA) is produced.
Specification
16.The specification as accepted relates to a method for the causticisation of alkaline solutions at elevated temperatures particularly as it relates to the Bayer process. Both experts agreed that conventional causticisation in the Bayer process was typically conducted on dilute solutions[7] just below the boiling point of the Bayer liquor (105oC) [8] at between 95 and 100oC.[9] At that temperature, a reaction time of around 1 hour was required to ensure complete conversion to calcium carbonate[10].
[7] One of the known difficulties in causticisation is that the reaction is reversible. Hence relatively high concentrations of sodium hydroxide will shift the equilibrium of the reaction to favour sodium carbonate which means it is difficult to obtain the complete conversion of sodium carbonate in concentrated alkaline solutions.
[8] Armstrong#1 at [4.18]
[9] Power#1 at [68]
[10] Opposed specification at page 3, lines 11-13
17.The specification noted a number of difficulties with the conventional causticisation process. In particular, it:
·was seemingly limited to an upper causticisation efficiency threshold (TC/TA);
·produced an undesirable by-product (TCA); and
·required a lengthy reaction time (1 hour)[11].
[11] Opposed specification at page 3, lines 1-13
18.The applicants found that these difficulties could be overcome if the causticisation process was performed at a higher temperature (above atmospheric boiling point) over a short residence time (less than 15 minutes). The specification postulated (without being bound by theory) that conducting the reaction at a higher temperature promotes the formation of calcium carbonate over the more thermodynamically preferred product (TCA)[12]. The higher temperatures therefore lead to less undesirable TCA if accompanied by short residence times.
[12] Opposed specification at page 17, lines 9-17
19.In example 2 of the opposed specification, a slaked lime charge (either 5, 7 or 12gL-1) was added to a pre-heated (145oC) (spent) liquor solution (with an initial TA of either 220, 240 or 260 gL-1)[13]. The results are presented in Figure 5 and table 4 (both reproduced below). Figure 5 plots the TC/TA ratios (causticisation efficiency) against reaction time using the three different lime charges. It shows the greatest net increase in TC/TA ratios with short residence periods (particularly where high lime charges are used).
[13] Opposed specification at page 14, lines 21 – page 18, line 20
20.Table 4 compares the lime efficiencies obtained using three different lime charges and two residence periods (30 seconds and 30 minutes). Significantly higher lime efficiencies were obtained when the short residence time (30 seconds) was used (with all 3 lime charges).
21.In example 2, the causticisation efficiency maximised after 30 seconds to around 0.82-0.83 TC/TA[14]. Example 4 (which used a different slaked lime slurry source) achieved higher TC/TA results (between 0.88-0.92)[15] which also maximised within 5 minutes[16].
[14] Opposed specification table 2, page 16
[15] Opposed specification table 7, page 22 and note comments on page 15, lines 15-18
[16] Opposed specification page 20, lines 2-3
22.The specification ends with 54 claims with two (non-omnibus) independent claims (claims 1 and 28). While the description particularly relates to the Bayer process, claim 1 is not limited to this process and therefore encompasses other processes where causticisation is used (most notably the Kraft (paper pulping) process). Claim 1 reads as follows:
1. A method for the causticisation of an alkaline solution, the method characterised by the step of:
Adding a quantity of lime to the alkaline solution to produce a reaction mixture in such a manner that the reaction temperature of the reaction mixture so produced rapidly exceeds the atmospheric boiling point of the alkaline solution, the residence time of the quantity of lime in the alkaline solution being less than 15 minutes.
23.In contrast, claim 28 is limited to the Bayer process. It reads as follows:
28. A method for causticisation of a Bayer process solution, the method characterised by the steps of:
Obtaining the Bayer process solution from a Bayer circuit as a side stream
Heating the Bayer process solution to a predetermined temperature exceeding 110oC
Adding a quantity of lime to the heated Bayer Process solution to form a reaction mixture in such a manner that the temperature of the reaction mixture rapidly exceeds the atmospheric boiling point of the Bayer process solution;
Passing the reaction mixture into a reaction vessel;
Retaining the reaction mixture in the reaction vessel for a period not exceeding 15 minutes to generate a causticised Bayer process solution; and
Returning the causticised Bayer process solution to the Bayer circuit.
Claim construction and related section 40/utility issues
Relevant Principles of Construction
24. As noted by the Full Court in Pfizer Overseas Pharmaceuticals v Eli Lilly [2005] FCAFC 224 at [250]), underlying any approach to claim construction is that a patent is a document which confers a public monopoly and is not to be construed merely as a written document inter partes[17] . The first (and most basic) rule of claim construction is therefore that claims are given their ‘plain meaning’. This rule was explained Sheppard J in Décor Corp v Dart Industries 13 IPR 385 at 400 as follows:
[17] Pfizer Overseas Pharmaceuticals v Eli Lilly [2005] FCAFC 224 at [247]
‘The claims define the invention which is the subject of the patent. These must be construed according to their terms upon ordinary principles. Any purely verbal or grammatical question that can be answered according to ordinary rules for the construction of written documents is to be resolved accordingly.’
25. It is also well-established law that where a claim is clear, it is not legitimate ‘to confine the scope of the claims by reference to limitations which may be found in the body of the specification but are not expressly or by proper inference reproduced in the claims themselves’[18]. This approach was ratified by the High Court in Interlego AG v Toltoys Pty Ltd [1973] HCA 1; (1972) 130 CLR 461 (at 478):
[18] Décor Corp v Dart Industries 13 IPR 385 at 400
‘... the settled rule is that in ascertaining the width of a particular claim it is not permissible to vary or qualify the plain and unambiguous meaning of the claim by reference to the body of the specification.’
26. The courts have however also recognised that where there is a genuine ambiguity in the claims, this should be generally resolved in the applicant’s favour. As noted by the Full Court in Pfizer Overseas Pharmaceuticals v Eli Lilly [2005] FCAFC 224 at [250][19]):
[19] Quoting Welch Perrin & Co Pty Ltd v Worrel [1961] HCA 91; (1961) 106 CLR 588 (at 610)
‘... it is right to construe a claim with an eye benevolent to the inventor and with a view to making the invention work – this is an application of the old doctrine ut res magis valeat quam pereat – and it is illustrated in Nobel’s Case [(1894) 11 RPC at 524].’
Construction of claim 1 and related validity issues
‘Residence time’
27. A critical issue in this opposition concerned the construction of the term “residence time” in claim 1. At the hearing, the applicant argued that there were two alternative constructions for this term[20]:
[20] Applicant’s submissions at [52]
(a)‘Residence time’ means the period of time that the reaction mixture is under the claimed causticisation conditions. It starts when the reaction mixture enters the reaction vessel and ends when the mixture leaves the reaction vessel.
(b)‘Residence time’ means the total period of time the lime is in contact with the alkaline solution. It starts when the lime is added and ends when the lime is finally separated from the alkaline solution. It therefore includes the time before, during and after the causticiser vessel (the opponent referred to this construction as the ‘go to whoa’ construction).
28. The applicant’s preferred construction was that the term ‘residence time’ has the first meaning (‘time in the causticiser’). They noted that this was how the term was commonly used in the prior art and aligns better with how the invention would be applied in an industrial setting. They also argued that it was more consistent with the specific Bayer process defined in claim 28 and would therefore address most of opponent’s clarity and inutility concerns.
29. I accept that the word was commonly used in the art to mean time spent in a particular reaction vessel. The skilled person would therefore find some ambiguity in the longer phrase which appears to qualify the term as being relative to the presence (quantity) of lime in the alkaline solution (ie: the second construction):
“the residence time of the quantity of lime in the alkaline solution being less than 15 minutes”
30. Although both experts applied the second construction in their evidence[21], the first construction would nonetheless be consistent with the claim in its entirety if the phrase ‘the quantity of lime in the alkaline solution’ is simply read as an antecedent for an earlier occurring phrase:
[21] Opponent’s submissions at [60] and note Power#1 at [554], Power#2 at [33] and [38], Armstrong#3 at [26], Armstrong#5 at [31]-[33], Armstrong#6 at [48] and [66]
Adding a quantity of lime to the alkaline solution to produce a reaction mixture in such a manner that the reaction temperature of the reaction mixture so produced rapidly exceeds the atmospheric boiling point of the alkaline solution, the residence time of the quantity of lime in the alkaline solution being less than 15 minutes.
31. There is therefore a clear ambiguity regarding the term ‘residence time’. I am unable to resolve this ambiguity from the specification as a whole because both constructions lead to a shorter causticisation time consistent with the promise of the invention. However I agree that the applicant’s latest construction is a better fit with the process steps of claim 28 and how the process would work in practice.
32. I note the courts preference to resolve genuine ambiguities in a claim in the applicant’s favour. While the above quotation refers to finding a ‘dictionary definition’ in the specification, I believe the same principle can be applied in the current case where the applicant’s intended construction is consistent with the teaching of the specification. I will therefore proceed in this decision on the assumption that the applicant’s preferred construction applies (ie: ‘time in the causticiser’). However I note that the term is ambiguous and that this leads to a clarity problem in claim 1 (and its dependent claims).
33. This applicant’s preferred construction obviates the opponent’s primary utility argument. According to the opponent, the separation of lime wasn’t achievable in an industrial setting within 15 minutes and as a consequence the invention couldn’t work. The first construction doesn’t require the separation of lime within 15 minutes and hence the utility argument is no longer relevant. I therefore find the invention meets the usefulness requirements of section 18(1)(c).
‘rapidly exceeds’
34. Regardless of which construction applied to the term ‘residence time’, the opponent argued that the phrase “adding a quantity of lime…in such a manner that the reaction temperature of the reaction mixture so produced rapidly exceeds the atmospheric boiling point” (present in both claims 1 and 28) was unclear. According to the opponent, the term ‘rapidly exceeds’ implies the reaction mixture was initially below atmospheric boiling point and then rapidly exceeds this when the lime is added. The opponent observed that all the examples start with solution where the temperature is already above the atmospheric boiling point before lime is added and doesn’t increase with the addition of lime[22]. Hence they suggested that the manner by which a quantity of lime can be added to achieve a ‘rapid increase’ is unclear. They further argued that because none of the examples actually show a rapid increase in temperature with the addition of lime, the specification does not contain a best method of performance.
[22] all the examples use slaked lime rather than quicklime so the temperature will be static on the addition of lime – see Armstrong#6 at [31]
35. I note that the specification clearly teaches that the promise of the invention can be achieved if the reaction mixture is already at the correct temperature before the addition of lime. In fact, the specification used slaked lime which does not increase the temperature when added. The addition of lime therefore doesn’t need to cause a rapid increase in temperature and the specification therefore does not suggest that the rate at which a certain temperature is reached in causticisation is critical. In fact, the term ‘exceed’ doesn’t imply a rate of increase but achieving a level above a set limit (in this case a particular temperature). Given this, the claims could therefore be construed to merely require that the reaction mixture itself has to ‘rapidly’ exceed a particular temperature by some (unspecified) means once lime is present.
36. Dr Power certainly came to the same understanding:
“I consider that the term “in such a manner” in the phrase to produce a reaction mixture in such a manner that the reaction temperatures of the reaction mixture so produced rapidly exceeds the atmospheric boiling point of the alkaline solution is merely a general way of saying that the temperature of the reaction mixture must be above the atmospheric boiling point and may be brought above the atmospheric boiling point in any number of ways” [23]
[23] Power#1 at [180]
37. I agree that the claims could have been better drafted as read in isolation from the specification they infer that the lime is causing the increase in temperature. However as noted above, the invention resides in rapidly achieving a set temperature and I note that neither expert had any real problems understanding the invention or the claims. In my view, the phrase “adding a quantity of lime…in such a manner that the reaction temperature of the reaction mixture so produced rapidly exceeds the atmospheric boiling point” means that the reaction mixture quickly exceeds atmospheric boiling point. The claims are therefore clear. In addition, because the examples all describe a reaction mixture which was above the atmospheric boiling point when lime was added, the specification is fully described.
Novelty
Relevant Law
38. The question of novelty is determined under the provisions of subsection 7(1) of the Patents Act (Cth) which relevantly reads as follows:
(1) For the purposes of this Act, an invention is to be taken to be novel when compared with the prior art base unless it is not novel in the light of any one of the following kinds of information, each of which must be considered separately:
(a) prior art information (other than that mentioned in paragraph (c)) made publicly available in a single document or through doing a single act;
(b) prior art information (other than that mentioned in paragraph (c)) made publicly available in 2 or more related documents, or through doing 2 or more related acts, if the relationship between the documents or acts is such that a person skilled in the relevant art would treat them as a single source of that information;
(c) ……
39.The basic test for novelty is the "reverse infringement test" as set out in Meyers Taylor Pty Ltd v Vicarr Industries [1977] HCA 19; (1977) 137 CLR 228 at page 235 where Aickin J stated:
"The basic test for anticipation or want of novelty is the same as that for infringement and generally one can properly ask oneself whether the alleged invention would if the patent were valid, constitute an infringement."
40.Infringement is said to occur where "each and every one of the essential features of that claim have been taken" (Rodi and Wienenberger AG v. Henry Showell Ltd (1969) RPC 367).
41.However, as noted in Pfizer Overseas Pharmaceuticals v Eli Lilly and Company [2005] FCAFC 224 (see paragraphs 311 et seq), it is not sufficient for a citation to contain all the essential features of the claim, there must be “clear and unmistakable” directions to the claimed invention. In that regard, the Full Court referred to three key decisions:
(a) Canadian General Electric Co v Fada Radio Limited [1930] AC 97:
“...it is not enough to prove that an apparatus described in an earlier specification could have been used to produce this or that result. It must also be shown that the specification contains clear and unmistakeable directions to use it.”
(b) General Tire & Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 45:
“a signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee”
(c) ICI Chemicals v Lubrizol Corp [2000] FCA 1349; (2000) 106 FCR 214
‘... skilled addressees are not required to rummage through the prior patentee’s "flag locker" to find a "flag which the [prior patentee] possessed and could have planted".’
42.Novelty can however be found where a feature is not explicitly mentioned but nonetheless present as an inherent feature as an inevitable result of the disclosure. In this regard, the Full Court in Novozymes A/S v Danisco A/S [2013] FCAFC 6; 99 IPR 417 recently ratified the approach in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [supra] at page 486 which stated:
"if in carrying out the directions contained in a prior inventor's publication will inevitably result in something being made or done which, if the claim of the opposed specification were a claim of a valid patent, would constitute an infringement of that claim, then that claim would have been anticipated".
43.However as also observed by the same Court:
“ If ... the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee's claim, but would be at least as likely to be carried out in a way that would not do so, the patentee's claim will not be anticipated."
Relevant art
44.At the hearing, the opponent relied on the following documents:
D1: H. Theliander et al: (1996) The Causticizing Reaction-Equilibrium and Kinetics at Temperatures between 120 and 150oC. AlChE Symposium Series 92: 113-121 (‘Theliander’) [MLT-1]
D2 US patent 2 522 605 (Cundiff) published 10 January 1951 (‘Cundiff’) [MLT-2]
D4/D4a Australian patent application 58412/99 (based on international patent application WO 00/18684) published on 6 April 2000 with an earliest priority date of 25 September 1998 in the name of Worsley Alumina Pty Ltd (D4) and its provisional application PP6224 (D4a) filed on 25 September 1998 and published when the international application was published. (‘Worsley’) [MLT-4]
D12 Solymar and Zoldi “Lime in the Bayer Process – Present state and Future Trends” Light Metals 185-194 (1993) (‘Solymar’) [MLT-14]
Novelty Discussion
D1 (Theliander)
45.Theliander relates to the causticisation step in the Kraft (paper) pulp process. The Kraft process (outlined in annex A) uses sodium hydroxide to digest wood chips. The process creates a paper ‘pulp’ (precipitate) and a solution by-product containing both sodium hydroxide and sodium carbonate. The solution by-product is recycled back into the digestion process after a causticisation reaction (in which sodium carbonate is chemically converted to sodium hydroxide). This part of the process is very similar to the Bayer process (albeit without the competing reactions containing aluminate) and is therefore encompassed within the scope of claims 1-21.
46.Theliander studied the kinetics and equilibrium conditions of the causticisation reaction at temperatures between 120-150oC. This involved adding a slaked lime charge to a solution of sodium carbonate and measuring the rate of reaction at different temperatures. In their submissions, the applicant argued that D1 does not teach the need to rapidly obtain the high temperature[24]. However the rates of reaction were so fast (less than 1 minute)[25] that the skilled person would have clearly understood that the solution had to be pre-heated to the required temperature (before lime was added) so that the rates at different temperatures could be accurately compared. The apparatus used (illustrated in figure 1 below) also appears to be configured in such a way that lime would be added directly to the solution under pressure (at a high temperature).
[24] Applicant’s submissions 101(a)
[25] D1- page 117, column 1, lines 2-4
47.Theliander found that the reaction rate increased dramatically when the temperature was increased above the atmospheric boiling point. In particular, the reaction rate increased 10-20 times as the temperature was raised from 100 to 150oC. The study also reported that 55% of the lime reacted after 1 minute at 120oC and 67% of the lime reacting after 1 minute at 140oC[26]. Similar results were achieved at 130oC and 140oC.
[26] D1, page 117, column 1
48.The key data is presented in appendix B from Theliander (reproduced below) which tabulates NaOH and Na2CO3 concentrations sampled at various time points (sample points) and temperature ranges:
49.These results show that at each temperature, causticisation efficiencies continue to improve after 15 minutes (905 seconds) up to at least 110 minutes (6607 seconds). At 120oC, for example, 77% of the sodium carbonate reacted within 15 minutes increasing to 83% after 110 minutes. The skilled worker in seeking to maximise their causticisation efficiency would clearly be directed to use the conditions which provides the best outcome and be led to the longer reaction times. This is consistent with the equilibrium data referred to by the applicant which recommends causticisation periods of over an hour at each temperature[27]. As suggested by the applicant, the shorter time periods referred to in annex B are simply sample points in a kinetic (rate) study. When read as a whole, Theliander does not contain clear and unmistakeable directions to use a 15 minute residence period in causticisation. Hence none of the claims lack novelty in light of this document.
[27] D1 – page 116, column 1. The equilibrium data suggests a residence time of 60 minutes for 150oC, 90 minutes for 140oC and 130oC and 120 minutes for 120oC.
D2 (Cundiff)
50.The Cundiff patent relates to the causticisation of Bayer liquors. Although the main focus of the citation is an ‘outside causticisation’ process, it also discusses ‘inside causticisation’ as part of its admitted prior art. The opponent argued that both the inside and outside cautiscisation processes discussed in Cundiff fall within the scope of the claim. The two processes are outlined in figure 1 of the citation (reproduced below):
51.Inside causticisation is represented by the middle column in the figure above. It involves feeding the spent liquor directly back into either the digestion vessel (or the bauxite slurry) with lime. Causticisation would then occur concurrently with digestion at an elevated temperature (140-280oC) in a pressurized digester.
52.Cundiff doesn’t specify how long digestion occurs or how quickly the digestion mixture reaches the requisite temperature but Dr Armstrong believed that the process would take less than 15 minutes[28]. In practice, Dr Power argued that the process varied between about 10-60 minutes. Dr Power also noted that lime was commonly added to the bauxite slurry anywhere between a few minutes up to a few hours prior to digestion[29].
[28] Armstrong#1 at [5.18] and [4.19] for example
[29] Power#1 at [66]
53.In absence of any specific detail about the digestion process in the citation, the residence period could vary as Dr Power suggested. Further if lime was added prior to digestion, the mixture would not necessarily rapidly exceed atmospheric boiling point. Thus, while inside causticisation could occur in 15 minutes while rapidly exceed the atmospheric boiling point, I accept that it was at least as likely not to meet these conditions. As a consequence, the inside causticisation process does not provide clear and unmistakeable directions to the claimed invention.
54.The right hand column in the figure above represents the outside causticisation which was discussed in detail in Cundiff. This causticisation reaction was performed in a diluted spent liquor stream (total soda concentration of 125-175 g/L) at a high temperature (between 240 to 300oF (115-149oC)[30] under pressure. The authors found improved causticisation efficiencies (greater than 90%) using the higher temperature in contrast to the (then) teaching in the art that temperature did not matter[31].
[30] Converted using online converter at D2- column 3, lines 45 – column 4, line 18
55.Cundiff exemplified reaction times of from about ‘less than 20 minutes to three hours or over’. Their results are presented in table 2 (reproduced below):
56.Each reaction had a causticisation efficiency (C/S) of over 0.9 and a lime efficiency (% completed reaction[32]) of at least 85% (with an average of 89.1%). Cundiff noted that the reaction time did not materially affect causticisation efficiencies and was therefore not critical[33]. However, the citation also suggested that the ‘shortest possible [causticisation] time is the most desirable as it increases plant capacity per unit’. It further noted that longer treatment times increased alumina loss[34]. Given these results, the opponent argued that the skilled worker would be directed to use the shorter time period in causticisation (ie: less than 20 minutes).
[32] Lime efficiency is the relative proportion of lime converted to calcium carbonate rather than calcium aluminate
[33] D2- column 6, lines 45-52
[34] D2- column 6, lines 42-52
57.Although Cundiff suggests a short residence period, this was only in the (general) context of increasing plant capacity rather than improving the causticisation reaction itself. Cundiff had taught that reaction time was not important in the reaction[35] and hence its general teaching was to use any reaction time. The citation suggested that ‘longer treatment times’ increased alumina losses. However, I agree with the applicant that this comment could be referring to time periods outside the optimum residence time of 2 hours[36].
[35] D2- column 6, lines 45-52
[36] This is consistent with specific comments made in Young, R.C. “Chemistry of Bayer Liquor Causticisation”, Light Metals, 1982, Pages 97-117 [see page 104 paragraph 2 point (ii)] (D13) which was provided by the opponent as evidence of the CGK
58.While there might be cost benefits in having a short residence time, the skilled worker would also recognise that there are competing costs if causticisation was incomplete. There were no examples which used reaction times less than 20 minutes and the skilled person has no guidance of how long the reaction would need for completion. In that context, a recommended time period of ‘less than 20 minutes’ could be understood as a vague suggestion rather than a clear direction to use a 15 minute residence time.
59.Further because the citation had not recognised that a short residence time was critical, it contained no teaching for the reaction to rapidly exceed the atmospheric boiling point of the alkaline solution. Without a clear recommendation to rapidly heat the reaction mixture when (or before) lime was added, I am not convinced that the skilled person would necessarily have done so. As the applicant noted, the Cundiff examples appear to add lime to the reaction mixture at 82oC (180oF) for an undefined period before being heated by steam injection to 121oC (250oF) in an autoclave[37].
[37] Applicant’s submissions at 104, D2 at column 7, lines 14-17 and table I
60.This means that while the method might have been carried out in a manner which would infringe the claim, it would be at least as likely to be carried out in a way that would not do so (as per General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [supra] at page 486). There are therefore no clear and unmistakeable directions in Cundiff to rapidly exceed a temperature above atmospheric boiling point and as a consequence, all the claims are novel in light of this citation.
D4 AU 58412/99 (WO 00/18684) (Worsley) and D4a PP6224 (Worsley provisional)
61.WO 00/18684 (D4) is the international publication number associated with Australian application patent AU 58412/99 (patent 749809) by BHP Billiton Worsley Alumina Pty Ltd. The application was filed as PCT/AU99/00757 on 13 September 1999 with an Australian designation. Its earliest priority date was based on provisional application PP6224 (D4a) filed on 25 September 1998. The provisional and complete applications were both published with the international publication (6 April 2000). As indicated in the table below, these applications were not published until after the earliest priority date of the opposed application but they have an earlier priority date. Hence the documents are relevant for (‘whole of contents’) novelty but not inventive step.
| Application # | Earliest priority date | Filing date | Publication date |
| Opposed specification | 23 April 1999 | 1 November 2004 | 25 November 2004 |
| WO 00/18684 (AU 58412/99) | 22 September 1998 | 13 September 1999 | 6 April 2000 |
| PP6224 | 22 September 1998 | 22 September 1998 | 6 April 2000 |
| PQ2476 | 26 August 1999 | 26 August 1999 | 6 April 2000 |
62.The disclosures in both the provisional application (D4a) and standard application (D4) are the same and hence I will discuss them together. D4 and D4a (‘Worsley’) disclosed an improved method for the causticisation of Bayer liquors based on the understanding that the process could be separated into two distinct steps each of which could be individually optimised:
(1) lime reacts with aluminate ions to form a hydrocalumite species and hydroxyl ions; and
(2) the hydrocalumite species then reacted with the liquor to form calcium carbonate, aluminate ions and hydroxyl ions.
63.This is referred to as two-stage causticisation. By optimising the conditions separately for each step, Worsley could maximise the production of calcium carbonate and therefore improve lime utilisation and minimised alumina losses. The primary reaction was performed at low to moderate temperature (between 25-100oC but preferably between 70-80oC) with a residence time of between 5-30 minutes[38]. The secondary reaction was performed at a higher temperature (between 100 and 180oC and preferably at about 120oC). Residence time for the second reaction will vary dependent on a number of factors (in particular, temperature and presence of surfactants). The citation notes that at 103oC, the reaction will require 2 hours to reach completion but at 120oC (the preferred temperature), the reaction would be completed in 15 minutes[39].
[38] D4 – page 17, lines 6-21
[39] D4 – page 17, line 30 – page 18, line 6
64.However as the applicant noted, the addition of lime only occurs at the first (lower temperature) step. By the time the temperature is increased, only hydrocalumite is present which means that the reaction mixture had not rapidly exceeded atmospheric boiling point when lime was present. There are therefore no clear and unmistakable directions to ensure that the residence times (following the addition of lime) would be a total of 15 minutes (step 1 + step 2). As a consequence, none of the claims lack novelty in light of Worsley.
D12 (Solymar)
65.The Solymar article is a review article discussing the use of lime in regenerating caustic soda in the Bayer process. ‘Quasi-equilibrium data’ of the causticisation reaction was determined in a plant process liquor by means of a lime milk charge (0.62 moles CaO/mole of Na2CO3) at different selected temperatures. Data was sampled at 15 minutes and the results graphed in figure 9 (reproduced below):
66.As the opponent noted, the results indicate that increasing temperature improved the causticisation efficiency with the highest C/S results (0.94) being obtained at the highest temperature (240oC).
67.The applicant’s expert (Dr Power) argued that Solymar provided limited detail of their experimental methodology and it was not possible to determine exactly how long their sodium carbonate solution was in contact with lime. In his view, ‘sampling’ time in figure 9 was likely to mean the time of sampling after the mixture reaches the desired temperature (including heat up time) rather than the total time that the lime was in contact with the sodium carbonate[40].
[40] Power#1 at [621]-[622]
68.However, if a skilled person wanted to directly compare reaction rates across different temperatures at a specific (short) time point, they would understand that reactants have to be combined once the requisite temperature was reached (ie: pre-heated). If this were not the case, any observed data variations could be the result of a longer incubation period rather than the different temperature[41]. My view is therefore that Solymar has disclosed the feature of the reaction ‘rapidly exceeding’ the atmospheric boiling point.
[41] Given that it would take longer to heat a reaction to the higher temperatures
69.Despite this, I agree with the applicant that figure 9 simply provides a snapshot of data (‘sampling time’) taken at 15 minutes without necessarily teaching that the causticisation process should be conducted over the same time frame[42]. The study was simply looking at rates of reaction under different conditions at a specific time point. The skilled worker would understand the term ‘quasi-equilibrium’ to mean that the reactions have not been performed to completion. Without a clear recommendation to alter long-term industry standard causticisation conditions (1 hour at a particular temperature), there is nothing in figure 9 which would lead the skilled person to causticise for a shorter period.
[42] Power#1 at [611] et seq
70.As a consequence, when read in the light of CGK, there are no clear and unmistakable directions for the skilled worker to complete causticisation in 15 minutes or less. Solymar therefore does not deprive any of the claims of their novelty.
Inventive step
Relevant Law
71.Section 7(2) provides that an invention is taken to involve an inventive step when compared to the prior art base unless it would have been obvious to a person skilled in the relevant art in the light of common general knowledge within Australia either considered alone or together with information made publicly available anywhere in the world. Section 7(3) restricts the information to that which could be reasonably expected to have been ascertained, understood and regarded as relevant by the person skilled in the relevant art.
72.Inventive step may be assessed having regard to the reformulated so-called ‘Cripps question’ set out in Aktiebolaget Hassle v Alphapharm Pty Limited [2002] HCA 59; 212 CLR 411 at [53]:
“Would the notional research group at the relevant date in all the circumstances … directly be led as a matter of course to try [the claimed invention] in the expectation that it might well produce [the desired result]?”
73.To provide some context to that question, the Courts commonly determine the “starting point” for considering inventive step in terms of an existing problem for which the inventor found a solution. As noted by High Court in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd (no. 2) [2007] HCA 21 at [105]:
“While not every invention constitutes a solution to a problem, it is commonplace so to describe an invention where it is appropriate to do so”
74.Recent Federal Court decisions have followed this approach. Thus in Ranbaxy Laboratories Ltd v AstraZeneca AB [2013] FCA 368 (23 April 2013) ([203]-[218]), Justice Middleton cited Jagot J’s comments in Apotex Pty Ltd v AstraZeneca AB (No 4) [2013] FCA 162 with approval:
“In assessing obviousness, it is necessary first to determine the nature of the claimed invention and the inventive step described in the Patent. This may involve ascertaining the “starting point” of the inventive step, sometimes described in terms of an existing problem for which the inventor found a solution. The obviousness of the invention as claimed is then assessed by reference to common general knowledge in Australia at the priority date.”
Inventive step based on the Common General Knowledge
75.Both parties acknowledged that in April 1999, it had been conventional practice across the alumina industry to causticise liquors at temperatures less than boiling point for at least 1 hour. As Dr Power noted, these conditions had been employed in the industry for over 20 years and he considered that no thought had been given to operate at temperatures higher than boiling point or controlling the rate of temperature rise of the liquor[43].
[43] Power#1 at [178] and [615]
76.Dr Armstrong conceded that both the reaction period (less than 15 minutes) and the temperature of reaction (greater than atmospheric boiling point) were unusual[44]. However he suggested that it had been generally recognised that the rate of causticisation increased at higher temperatures and that it would be beneficial to reduce the time period of the causticisation reaction so as to reduce the formation of TCA[45]. In his view, it was therefore obvious to employ these conditions in the Bayer causticisation process.
[44] Armstrong#1 at [4.19] and [4.24] – note that temperatures above atmospheric boiling points would require pressure vessels and other special equipment to perform
[45] Armstrong#1 at [3.27]
77.However Cundiff recognised as early as 1950 that higher reaction temperatures increased the rate of causticisation and this knowledge had been well-known for a considerable time by April 1999. If the skilled worker had realised that short residence periods were particularly beneficial (because they produce less TCA), it is unclear why a competitive industry (such as aluminium manufacture) had failed to adopt these conditions. As Dr Power noted, this is a strong indicator of an inventive step.
78.The evidence indicates that the relationship between residence time and increased TCA levels had been understood for reaction periods over 2 hours[46]. However the opponent did not establish that a shorter residence times (less than 15 minutes) could minimise TCA further. Thus while the skilled worker had known that high temperatures would increase reaction rate, they had not recognised that the combination of a (particularly) short residence time and high temperature had additional benefits. Without this recognition, there is no clear motivation to use rapid heating and a shorter residence time and the skilled person is not directly led to the claimed invention. As a consequence, the opponent has not established that any of the claims lack an inventive step in light of the CGK.
[46] See novelty discussion above relating to the Cundiff citation
Inventive step based on the relevant cited art
79.Three of the documents used for novelty purposes (D1, D2 and D12) were published prior to the earliest priority date and hence potentially form part of the prior art base for inventive step. However none of these documents (even if they had been ascertained, understood or regarded as relevant) add anything over and above CGK. In particular, none of the documents teach that a short residence time (less than 15 minutes) is critical to the causticisation reaction at high temperatures. The skilled worker would therefore not be adopt these conditions in place of the standard causticisation process currently employed in the industry. Thus, in my view, none of these documents deprive any of the claims of their inventive step.
Manner of Manufacture
The opponent argued that the claimed methods were not a manner of manufacture because they failed the threshold test of inventiveness on the face of the specification (as per NV Philips Gloeilampenfabrieken v Mirabella Pty Ltd (1995) 183 ALR 655; Advanced Building Systems Pty Ltd v Ramset Fasteners (Aust) Pty Ltd (1998) 152 ALR 604 and Merck Inc v Arrow Pharmaceuticals Limited [2006] FCAFC 91].
81.However this argument merely restates the opponent’s novelty and inventive step case which has already been considered in detail above. I therefore do not propose to consider the issue further under this ground. For the same reasons outlined above under novelty and inventive step, the claims define a manner of manufacture.
Conclusion
82.Claim 1 with regard to the term ‘residence time’ is ambiguous and therefore lacks clarity. The applicant’s first construction (time in the reaction vessel) was however adopted for the purposes of section 40, section 18, novelty and inventive step.
83.Based on the applicant’s preferred construction, there are no other clarity difficulties. The phrase “adding a quantity of lime…in such a manner that the reaction temperature of the reaction mixture so produced rapidly exceeds the atmospheric boiling point” is clear. The term ‘exceed’ doesn’t imply a rate of increase but a level above a set limit (in this case a particular temperature). The requirement that this should happen quickly (‘rapidly’) is a requirement of the reaction mixture itself without necessarily being the result of adding lime.
84.Based on the applicant’s preferred construction, the time taken to separate the lime is not included in the 15 minute window and the utility difficulties referred to by the opponent in their evidence are no longer relevant. As a consequence, the claims are all useful.
85.None of the citations provided by the opponent deprive any of the claims of their novelty or inventive step. They do not teach that a short residence time (less than 15 minutes) is critical to the causticisation reaction at high temperatures. The skilled worker would therefore not be led to adopt these conditions in place of the standard causticisation times currently employed in the industry.
86.In my view, the specification contains patentable subject matter. I allow the applicant 60 days from the date of this decision to propose amendments to overcome the deficiencies noted above in this decision.
Costs
87.In matters before the Commissioner, costs normally follow the event. The opposition is partly successful with regard to a significant issue of clarity based on an alternative construction raised by the applicant at the hearing. In these circumstances, I consider that costs should follow the event and I award costs against the applicant Alcoa of Australia Limited.
Karen Ayers
Delegate of the Commissioner of Patents
Annex A
Kraft Paper Pulp process
The Kraft process is schematically represented as follows[47]:
[47] Figure from H. Tan and E.K. Vakkilainnen: The Kraft Chemical Recovery Process as sourced from to the Bayer process, the Kraft process contains a digestion step involving sodium hydroxide producing a precipitate (in this case paper pulp) and a caustic solution which can be recycled back to digestion through a causticisation step involving lime. The causticisation reaction is the same as in the Bayer process (but without the competing reactions with aluminate).
The process involve the following steps:
·A mixture of sodium hydroxide and sodium sulphide (known as ‘white liquor’) is used to remove lignin from the cellulose in wood chips (Digestion). This process produces a solid pulp and a ‘black liquor’ (containing sodium sulphate and sodium carbonate).
·The black liquor undergoes a 2 step recovery process before being recycled back into the Digestion process.
·The first step (recovery) regenerates sodium sulphide[48] and produces a ‘green liquor’.
[48] Sodium sulphide is produced by reducing sodium sulphate as per the reaction Na2SO4 +2C →Na2S + 2CO2
·The second step (causticisation) converts sodium carbonate to sodium hydroxide using lime[49] (regenerating the ‘white liquor’).
[49] Similar to the Bayer process, sodium carbonate is caused by the reaction of sodium hydroxide with organic carbonates
0
3
0