(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date Λ 23 February 2012 (23.02.2012) WO 2012/024294 Al (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every C22B 47/00 (2006.01) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, (21) International Application Number: CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO, PCT/US201 1/047916 DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, (22) International Filing Date: HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, 16 August 201 1 (16.08.201 1) KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, (25) Filing Language: English NO, NZ, OM, PE, PG, PH, PL, PT, QA, RO, RS, RU, (26) Publication Language: English SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, (30) Priority Data: ZW. 61/374,691 18 August 2010 (18.08.2010) US (84) Designated States (unless otherwise indicated, for every (71) Applicant (for all designated States except US): AMER¬ kind of regional protection available): ARIPO (BW, GH, ICAN MANGANESE INC. [CA/US]; 2533 North Car GM, KE, LR, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, son Street, Suite 3913, Carson City, NV 89706 (US). ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, (72) Inventors; and EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (75) Inventors/ Applicants (for US only): CHOW, Norman LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, [CA/CA]; 6608 East Boulevard, Vancouver, BC V6V SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, 2M2 (CA). FISHER, John, W. [CA/CA]; 2628 Gun- GW, ML, MR, NE, SN, TD, TG). whale Road, Pender Island, BC VON 2M2 (CA). WARKENTI, Douglas [CA/CA]; 745 East 30th Avenue, Declarations under Rule 4.17 : Vancouver, BC V5V 2V8 (CA). NACU, Anca-mihaela — as to applicant's entitlement to apply for and be granted [CA/CA]; #507 - 1199 Seymour Street, Vancouver, BC a patent (Rule 4.1 7(H)) V6B 1K3 (CA). — as to the applicant's entitlement to claim the priority of (74) Agent: PUNTIGAM, Clark, A.; 2033 6th Avenue, Suite the earlier application (Rule 4.17(Hi)) 1020, Seattle, WA 98121 (US). [Continued on next page] (54) Title: PROCESSING OF MANGANOUS SULPHATE/DFTHIONATE LIQUORS © (57) Abstract: The process concerns hydrometallurgical processing of manganese sulphate and manganese dithionate containing liquors and recovery of water therefrom. Sodium sulphate and/or sodium dithionate containing liquors are derived from man ganese sulphate and manganese dithionate containing liquids, which are then cooled to produce crystals of sodium sulphate dec o ahydrate and sodium dithionate dehydrate. The sodium sulphate decahydrate and sodium dithionate dehydrate crystals are then heated to a temperature sufficient to decompose the sodium sulphate decahydrate crystals to form anhydrous sodium sulphate crystals, sodium dithionate hydrate crystals and water, after which water is removed from the sodium sulphate and sodium dithion o ate hydrate crystal. The sodium sulphate and sodium dithionate dehydrate crystals are then heated to form anhydrous sodium sul phate, sulfur dioxide and water or steam. The anhydrous sodium sulphate is then separated from the sulfur dioxide and water. w o 201 2/024294 Al IIII 111II 11111 Hill lllll 11III III Hill 11 III I I I I I III II 11 II Published: before the expiration of the time limit for amending the — with international search report (Art. 21(3)) claims and to be republished in the event of receipt of amendments (Rule 48.2(h)) Description PROCESSING OF MANGANOUS SULPHATE/DITHIONATE LIQUORS Prior Application This non-provisional application claims the priority of prior U.S. provisional application Serial No. 61/374,691 , filed on August 18, 2010. Technical Field [0001] The present invention relates to the recovery of water and sodium sulphate from sodium sulphate and sodium dithionate containing liquors such as those derived from hydrometallurgical processing of manganese containing resource material. Background of the Invention [0002] It is generally known that manganese may be leached from higher valent manganese (Mn) containing resource material, such as manganese dioxide, using sulphur dioxide alone or in combination with sulphuric acid to produce manganous sulphate and manganous dithionate. This is described for example in WO 2004/033738 to Ward: Mn02 + S0 2 = MnS0 4 [1] Mn0 + 2S02 = MnS 0 [2] The manganous dithionate (MnS20 ) precludes proper control for electrowinning high purity Mn metal and must be removed before electrolysis. Henn et al ("Review of Major Proposed Processes for Recovering Manganese from United States Resources", U.S. Bureau of Mines, Information Circular 8368, 1968) describes different methods of converting MnS 0 to MnS0 4. One method describes autoclaving the MnS 0 containing pregnant leach solution at 230 °C and 600 psi with air. MnS 20 conversion to MnS0 4 would proceed according to the following reaction: → MnS 0 6 + ½ 02 + H 0 MnS0 + H2S0 4 [3] [0003] Although autoclaving can convert MnS20 to MnS0 4 and H S0 , it requires the use of an expensive corrosion resistant pressure vessel. Process challenges with this technique include inefficient use of SO2 and potential precipitation of manganous sulphate due to its inverse solubility with increasing temperature, as shown in Figure 1. Controlling optimum concentration of Manganous sulphate in solution is desirable for electrowinning as is the need to develop an effective scheme to process the H2SO4 by-product in combination with the MnSC . Henn's report mentions that the H2SO4 could be used to consume non-manganese oxides to form insoluble sulphates. This would involve reacting the pregnant leach solution with more resource material in the autoclave. While not mentioned in the Henn report, a perfect balance between H2SO4 by-product generation and consumption of non-manganese material to form insoluble products is unlikely. Insufficient acid consuming material would have to be supplemented with the addition of lime to consume excess H2SO4. Controlled lime addition would be required as over addition may cause manganese precipitation, resulting in loss of product. [0004] One of the techniques described in the Henn report uses evaporation to crystallize MnSO4 H20 from aqueous solution i.e. manganous sulphate containing liquor is evaporated via heating to release water so as to concentrate manganous sulphate above its solubility limit. A report by Allen ("Recovery of Manganese from Low-Grade Ores", Chemical Engineering Progress, Vol 50, No. 1, 1954, pp 9-13) describes methodology to evaporate the pregnant leach solution to form MnS0 4 and MnS20 crystals. Sintering the crystals at 1100 to 1200 °C produces a M¾0 4 product as well as evolve SO2 gas which can be recycled to the leach. The high temperature for sintering was used in this case in order to decompose MnS0 4 into M¾04 and SO2. [0005] Prior art techniques for recovering manganese metal from low grade manganese resource material via sulphite leaching techniques resulting in the formation of manganous sulphate (MnS0 4) and manganous dithionate (MnS206) containing liquors have the following problems: 1) Destruction of manganous dithionate in the presence of manganous sulphate under conditions which favour undesirable manganous sulphate precipitation i.e. high temperature and pressure plus reactor corrosion due to high temperature sulphuric acid formation (see reaction [3] above), and 2) Expensive evaporative crystallization of manganous sulphate containing liquor. Summary of the Invention [0006] Accordingly, disclosed herein is a process for hydrometallurgical processing of manganese sulphate and manganese dithionate containing liquors and recovery of water therefrom, comprises the steps of: deriving sodium sulphate and/or sodium dithionate containing liquors from manganese sulphate and manganese dithionate containing liquids; crystallizing sodium sulphate decahydrate and sodium dithionate dehydrate by cooling sodium sulphate/sodium dithionate containing liquor with or without a vacuum; heating the sodium sulphate decahydrate and sodium dithionate dehydrate crystals to a temperature sufficient to decompose the sodium sulphate decahydrate crystals to form anhydrous sodium sulphate crystals, sodium dithionate hydrate crystals and water; removing water from the sodium sulphate and sodium dithionate hydrate crystals; heating the sodium sulphate and sodium dithionate dehydrate crystals to form anhydrous sodium sulphate, sulfur dioxide and water or steam; and separating the anhydrous sodium sulphate from the sulfur dioxide and water. Brief Description of the Drawings [0007] Figure 1 is a known graph of temperature solubility of manganous sulfate. [0008] Figure 2 is a diagram of the overall system/process described herein. Best Mode for Carrying Out the Invention [0009] Figure 2 shows the overall system/process disclosed herein. Manganese dioxide containing resource material is fed through a grate into a hammer mill 1 and from there to a trommel screen 14. Minus 30 mm resource material is stockpiled for feed into a leach system, whereas oversized material is recycled back to the hammermill. [00010] The minus 30 mm resource material from the milling circuit is preleached with a sulphuric acid solution in a series of stirred tanks shown at 16. The resource material pulp density is 12 to 20% by weight to facilitate subsequent solid liquid separation with a leach thickener. The resource material disintegrates into smaller particles as a result of the agitation at this stage. Acid consuming resource material, e.g. calcium and barium, react with the sulphuric acid to form insoluble sulphates.