Mitsubishi Chemical Industries Ltd. v. Asahi Kasei Kogyo Kabushiki Kaisha

[1988] APO 38

In the Matter of the Patents Act 1952 - and - In the Matter of Application No. 542274 for a Patent by MITSUBISHI CHEMICAL INDUSTRIES LTD. - and - In the Matter of Opposition thereto under Section 59 by ASAHI KASEI KOGYO KABUSHIKI KAISHA.

 

DECISION OF A SUPERVISING EXAMINER OF PATENTS:

Background

Mitsubishi Chemical Industries Ltd. (Mitsubishi) lodged application No. 542274 entitled "Process for Producing Rare Earth Hydroxides", on 30 September, 1981. The office advertised acceptance thereof in the Official Journal of 14 February, 1985, and on.13 May, 1985, Asahi Kasei Kogyo Kabushiki Kaisha (Asahi) lodged notice of opposition under section 59. Asahi and Mitsubishi served their evidence as provided for under regulations 55, 56 and 57, Asahi finalising its evidence under the latter regulation on 23 September, 1987.

The matter came to hearing on 11 October, 1988 at the Sydney scheduled sessions. At the hearing Dr. M.G. Horner, assisted by Ms. Volga Vegar, represented Mitsubishi, and Mr. John O'Connor assisted by Dr. John McCann and Ms. Ann Cahill of Spruson & Ferguson represented Asahi.

The Specification

The invention relates to a process for producing rare earth hydroxides, more particularly from an ore containing rare earth phosphates. The specification concedes that:

"It has been known that an ore containing rare earth phosphates such as monazite is treated with a concentrated aqueous solution of sodium hydroxide to decompose the rare earth phosphates into the rare earth hydroxides and sodium phosphate and water is added to inhibit the precipitation of sodium phosphate and the resulting solid rare earth hydroxides are separated and the separated residual solution containing sodium phosphate and the unreacted sodium hydroxide is concentrated to give a boiling point of 1370C to precipitate and separate sodium phosphate as the crystal having a purity of 99% and the resulting aqueous solution of sodium hydroxide having a concentration of 47% is recycled to decompose the ore as disclosed in "Rare Earth" page 40-41 published by Shin Kinzoku Kyokai on September 1, 1962."

The specification points out that in the process for decomposing the ore containing the rare earth phosphates with a base, it is necessary to use excess sodium component at 3 molar ratio of the phosphate component in the ore; thus when the residual solution is treated in the conventional way, the sodium component bonded to the phosphate component is discharged as sodium phosphate out of the reaction system. Therefore, a large amount of expensive sodium hydroxide is needed. Further, it has proved difficult to recover satisfactory amounts of the sodium hydroxide.

The applicant has developed the present invention by recognising that an alkali metal phosphate can be easily converted into calcium and/or magnesium phosphate by the addition of calcium and/or magnesium hydroxide to an aqueous solution of an alkali metal phosphate after separating the resulting solid rare earth hydroxides obtained by the decomposition of the ore with a base; the resulting calcium and/or magnesium phosphate can be separated from the aqueous solution of alkali metal hydroxide at the ambient temperature and the residual aqueous solution can be recycled in the process. This results in more effective utilisation of the alkali metal hydroxide.

Claim 1 reads - "A process for producing rare earth hydroxides by treating an ore containing rare earth phosphates with an excess of an aqueous solution of an alkali metal hydroxide to decompose said rare earth phosphates into said rare earth hydroxides and an alkali metal phosphate and separating the resulting solid rare earth hydroxides from the aqueous solution of the alkali metal phosphate, wherein calcium and/or magnesium hydroxide is applied to said separated aqueous solution of the alkali metal phosphate, at a molar ratio to the alkali metal phosphate of at least 1.3:1, to convert said alkali metal phosphate in the solution into calcium and/or magnesium phosphate and an alkali metal hydroxide, said solid calcium and/or magnesium phosphate is separated from said aqueous solution of the alkali metal hydroxide and said aqueous solution is recycled to the decomposition of the ore."

The Evidence

The most relevant material appears in the evidence-in- reply, and comprises a declaration of Dr. H.N. Sinha exhibiting a published Russian research article and a verified translation thereof (HNS-15). The article is entitled "A Faster Method of Extracting Thorium and Rare Earths From Monazite by Alkali Treatment" by G.A. Meerson and Li Man Khek and appears in the journal, Investiya Akademi Nauk SSSR No. 1 Metals (1967). Edward Flowers, a University Librarian of the Auchmuty Library of the University of Newcastle, in a declaration states that, in his opinion, the publication would have been made available to the public within twelve months following its date of receipt; i.e. within twelve months following November 26, 1971.

Clearly the Russian article discloses matter which is very relevant to the present invention. Primarily, the article discloses a method of extracting thorium and rare earths by treating an ore containing rare earth phosphates (i.e. monazite) with an excess of sodium hydroxide. The article discloses that close to full regeneration of the sodium hydroxide spent in the treatment can be obtained by adding lime (which forms calcium hydroxide when added to water) to the treated solution. It goes on to state that the degree of sodium hydroxide regeneration is dependant on the amount of calcium hydroxide, and exemplifies a sodium hydroxide extraction amounting to 97% "with 130% Ca(OH)2 consumption vis-a-vis the stoichiometric amount". The end products of this treatment are the same as those of the present invention; i.e. rare earth hydroxide, sodium hydroxide and calcium phosphate. Clearly, the article discloses a process which falls within the scope of claims 1 to 3 and, at the-very least, is very relevant to the remaining claims. Dr. Horner conceded as much at the hearing, but he pointed out that as the article first came to light, so far as this action is concerned, in the evidence-in-reply, Mitsubishi have not had an opportunity of adducing material in answer thereto.

Decision

Because of the very relevant nature of the disclosure in the Russian article, I find it unnecessary to go into detail here. Clearly however, I would not be prepared to seal a patent on the application with the present statement of claims. Obviously, Mitsubishi will need to take further action before this matter can be satisfactorily concluded. It has a number of options. For example, it could propose amendments to the specification under section 77, or it could seek leave to adduce further evidence under sub-regulation 59(3), or it could pursue both courses of action, the latter being in support of the (proposed) amended specification. It might even withdraw the application. In any event, I direct that Mitsubishi initiate its chosen course of action within 60 days of the date of this decision. Until Mitsubishi makes known the course which it intends to pursue, it would not be appropriate for me to make an award of costs - I therefore reserve this question.

(J L Roveta)Supervising Examiner of Patents

27 0CT 1988

Patent Attorneys for the Applicant: Griffith Hack & Co. Patent Attorneys for the Opponent Spruson & Ferguson