DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The Amendment filed 8 January 2026 has been entered. Claims 1, 5, and 9-10 are amended; claims 15 is cancelled. Accordingly, claims 1-14 remain pending in the application. Applicant’s amendments to the claims have NOT overcome every 112(b) rejection previously set forth in the Non-Final Office Action mailed 8 September 2025.
Claim Objections
Claim 5 is objected to because of the following informalities:
Claim 5, lines 3-4, “alkaline earth metal sulphides that remains dissolved in the aqueous solution from the one or more sulphides of the alkali metal” should read “alkaline earth metal sulphides that remains dissolved in the aqueous solution of the one or more sulphides of the alkali metal” [emphasis added to indicate suggested changes] for consistency with the language used in claim 1, lines 5-6.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 6 and 9-10 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 6, line 2, recites "the residual alkaline earth metal recovery step is performed ahead of the second reaction step". It is unclear how the residual alkaline earth metal recovery step would be performed ahead of the second reaction step, as claim 5, lines 4-5, recite "reacting such residual alkaline earth metal with...CO₂ in gaseous form", and claim 1, lines 8-9, recite "reacting the one or more sulphides of the alkali metal with carbon dioxide (CO₂) in gaseous form, thus forming an aqueous solution of a bicarbonate of the alkali metal", such that the one or more sulphides of the alkali metal would necessarily react with the CO₂ to form a bicarbonate of the alkali metal during the reacting of the residual alkaline earth metal with CO₂.
Claim 10, line 4, recites "reacting the barium carbonate with alkali metal sulphate ahead of the first reaction step". It is unclear how the barium carbonate can be reacted with alkali metal sulfate ahead of the first reaction step, as the barium carbonate is produced after the first reaction step. Claim 6 requires the residual alkaline earth metal recovery step is performed ahead of or simultaneously with the second reaction step in lines 2 and 6, such that reacting the barium carbonate produced ahead of or simultaneously with the second reaction step with alkali metal sulphate necessarily occurs AFTER the first reaction step. Is the process continuous, such that the barium carbonate reacts with an alkali metal sulfate to form barium sulfate, which may then be recycled for use in the first reaction step? Clarification is requested as to how it may be possible to react the barium carbonate (which is produced ahead of or simultaneously with the second reaction step according to claim 6) with an alkali metal sulphate ahead of the first reaction step.
Claim 10, lines 5-6, recite "producing insoluble barium sulphate and recovering, in solid form, the residual alkaline earth metal that was dissolved in the aqueous solution of the one or more sulphides of the alkali metal". It is unclear if “the residual alkaline earth metal” recovered in line 6 is the barium carbonate or the barium sulphate. The recitation “and recovering, in solid form, the residual alkaline earth metal that was dissolved in the aqueous solution of the one or more sulphides of the alkali metal” appears to be redundant, as recovering insoluble barium sulphate is already recited in line 6.
Claim 9 is indefinite as it depends from an indefinite base and fail to cure the deficiencies of the base claim.
Allowable Subject Matter
Claims 1-5, 7-8, and 11-14 are allowed.
As allowable subject matter has been indicated, applicant's reply must either comply with all formal requirements or specifically traverse each requirement not complied with. See 37 CFR 1.111(b) and MPEP § 707.07(a).
The following is an examiner’s statement of reasons for allowance:
Claim 1 is allowable for disclosing a method of producing a carbonate or a bicarbonate of an alkali metal, in solid form, from a sulphate of the alkali metal, and elemental sulphur or sulphuric acid, the method including: in a first reaction step, reacting, in aqueous medium, a sulphate of an alkali metal with one or more alkaline earth metal sulphides, thus forming an aqueous solution of one or more sulphides of the alkali metal and one or more sulphates of the alkaline earth metal in solid form; in a second reaction step, in the aqueous solution of one or more sulphides of the alkali metal, reacting the one or more sulphides of the alkali metal with carbon dioxide (CO2) in gaseous form, thus forming an aqueous solution of a bicarbonate of the alkali metal and gaseous hydrogen sulphide; in a recovery step, recovering a carbonate or the bicarbonate of the alkali metal, in solid form, from the aqueous solution of the bicarbonate of the alkali metal; in an alkaline earth metal sulphide regeneration step, regenerating one or more alkaline earth metal sulphides by subjecting one or more sulphates of the alkaline earth metal, formed in the first reaction step, to carbothermal reduction and thus obtaining one or more regenerated alkaline earth sulphides; and in a hydrogen sulphide processing step, converting the hydrogen sulphide to elemental sulphur or to sulphuric acid.
Nylander (US 3,134,639) discloses a process for producing an alkali metal carbonate from the corresponding alkali metal sulfate by adding calcium sulfide (calcium sulfide meets the limitation of one or more alkaline earth metal sulphides) to a solution (solution meets the limitation of an aqueous medium) of alkali metal sulfate to form a precipitate of calcium sulfate (precipitate of calcium sulfate meets the limitation of one or more sulphates of the alkaline earth metal in solid form) and an aqueous phase containing an alkali metal sulfide (claim 1). Nylander further discloses carbonating said aqueous phase to form a solution of alkali metal carbonate, and recovering from said solution an alkali metal carbonate (recovering alkali metal carbonate from the solution meets the limitation of recovering a carbonate of the alkali metal in solid form; claim 1). Nylander further discloses potassium bicarbonate (KHCO3) is also formed during carbonation (Col. 3, lines 43-50), such that Nylander meets the limitation of forming an aqueous solution of a bicarbonate of alkali metal. Nylander further discloses a solution of KHCO3 may be obtained, and when cooled, form crystals containing potassium carbonate (K2CO3) and KHCO3 (Col. 4. lines 20-26). Nylander further discloses the aqueous solution is carbonated with any suitable carbon dioxide-containing material; preferably with a carbon dioxide-containing gas (Col. 3, lines 62-64). Nylander further discloses the release of hydrogen sulfide during carbonation (Col. 3, lines 32-42), such that the hydrogen sulfide of Nylander is in gaseous form.
Nylander is silent to performing an alkaline earth metal sulphides regeneration step by subjecting the alkaline earth metal sulphate to carbothermal reduction.
Riley discloses a process comprising reacting CaSO4 (calcium sulfate) with a reducing agent such as C (carbon) to form CaS (calcium sulfide) in a roasting furnace (reduction with carbon as a reducing agent in roasting furnace meets the limitation of carbothermal reduction; Col. 2, lines 48-59). Riley further discloses mixing CaS with water and H2S (hydrogen sulfide) to form Ca(HS)2 (calcium hydrosulfide), and subjecting Ca(HS)2 to ion exchange with sodium ions to form NaHS (sodium hydrosulfide) and contacting NaHS with CO2 to form NaHCO3 (sodium bicarbonate) and H2S (contacting NaHS with CO2 to form NaHCO3 and H2S meets the limitation of the second reaction step; Col. 1, lines 40-47).
However, there is no motivation to combine Nylander and Riley, because Nylander teaches calcining limestone to lime followed by reacting the lime with hydrogen sulfide to form calcium sulfide, such that Nylander would not be motivated to produce calcium sulfide from gypsum in a reductive roasting process, as taught by Riley.
Additionally, Nylander already has a recycle of the hydrogen sulfide produced to react with the lime to form the calcium sulfide, such that Nylander would not be motivated to replace this efficient internal loop with the reductive roasting process of Riley to produce calcium sulfide, and further, Nylander would not be motivated to convert the hydrogen sulfide which is being recycled in the process to elemental sulphur or sulphuric acid, as required by claim 1.
Maree (US 5,035,807) discloses reacting a solution of calcium (an alkaline earth metal) and sulfate ions with barium (an alkaline earth metal) sulfide to form calcium sulfide and barium sulfate; reacting the calcium sulfide and barium sulfate with CO2 to form calcium carbonate, barium sulfide, and hydrogen sulfide (claim 1); and converting the H2S to sulphur (claim 5).
Maree, however, does not teach or suggest the use of an alkali metal in place of the alkaline earth metal, and therefore does not teach producing a carbonate or a bicarbonate of an alkali metal as required by claim 1.
Hazen (US 4,618,480) discloses treating a potassium (alkali metal) sulfate solution with lime (CaO) and hydrogen sulfide to form calcium (alkaline earth metal) sulfate and potassium sulfide, and treating the potassium sulfide with water and carbon dioxide to form potassium carbonate, potassium bicarbonate, and hydrogen sulfide (claim 19). Hazen further discloses a regenerating step of reducing barium (alkaline earth metal) sulfate with coal for form barium sulfide (claim 37). Hazen further discloses producing sulfur from the hydrogen sulfide (Col. 4, lines 35-37).
Hazen is silent to reacting the alkali metal sulfate with an alkaline earth metal sulfide to form the alkaline earth metal sulfate and alkali metal sulfide. Hazen utilizes lime and hydrogen sulfide as reactants instead of an alkaline earth metal sulfide, as required by claim 1. Additionally, although the regenerating step of Hazen includes reacting barium sulfate with coal to barium sulfide (carbothermal reduction), Hazen aims to regenerate barium oxide, not barium sulfide, as barium sulfide is only utilized to produce barium oxide in the process of Hazen.
Therefore, the elements of claim 1 are considered allowable.
Claims 2-5, 7-8, and 11-14 are considered allowable because they are dependent on claim 1.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Claims 6 and 9-10 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims.
Response to Arguments
Applicant's arguments, see “Remarks”, pg. 6, par. 5-pg. 7, par. 1, filed 8 January 2026, with respect to the rejections of claims 6 and 9-10 under 35 U.S.C. 112 have been fully considered but they are not persuasive.
Regarding claim 6, applicant argues there is no requirement/no need to require the gaseous CO2 of claim 5 be the same as the gaseous CO2 of claim 1 (per “Remarks”, pg. 6, par. 5).
However, it is unclear how ONLY a carbonate of the alkaline earth metal would be precipitated if gaseous CO2 was added to the aqueous solution of one or more sulphides of the alkali metal and one or more sulphates of the alkaline earth metal. It does not appear to be possible to use gaseous CO2 in the residual alkaline earth metal recovery step ahead of the second reaction step, because the second reaction step would occur simultaneously with (not after) the residual alkaline earth metal recovery step, because adding CO2 to the aqueous solution comprising one or more sulphides of the alkaline metal would form an aqueous solution of a bicarbonate of the alkali metal and gaseous hydrogen sulphide, as stated in claim 1, lines 7-10. Absent a showing of unexpected results, the addition of CO2 in gaseous form would precipitate the carbonate of the alkaline earth metal AND form an aqueous solution of a bicarbonate of the alkali metal, simultaneously. Clarification is requested as to how it may be possible to add CO2 to the aqueous solution and precipitate ONLY a carbonate of the alkaline earth metal AHEAD of adding CO2 to form a bicarbonate of the alkali metal and gaseous hydrogen sulphide (see rejection of claim 6 under 35 U.S.C. 112(b)).
Regarding claim 10, applicant argues the amendments overcome the rejection of claim 10 (“Remarks”, pg. 7, par. 1).
However, the amendments to claim 10 do not overcome the rejection of claim 10, as it is still unclear how the barium carbonate can be reacted with alkali metal sulfate ahead of the first reaction step, and it is unclear if “the residual alkaline earth metal” recovered is the barium carbonate or the barium sulphate (see rejections of claim 10 under 35 U.S.C. 112(b)).
Applicant’s arguments, see "Remarks", pg. 8, par. 2-pg. 9, par. 6, filed 8 January 2026, with respect to the rejection of claims 1-14 under 35 U.S.C. 103 have been fully considered and are persuasive. The rejection of 8 September 2025 has been withdrawn.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/S.E.S./Examiner, Art Unit 1735
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735