(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 WO 2016/054683 Al 14 April 2016 (14.04.2016) P O P C T (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every C22B 26/12 (2006.01) C22B 3/08 (2006.01) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, (21) International Application Number: BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, PCT/AU20 15/000608 DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, (22) International Filing Date: HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR, October 2015 (09. 10.2015) KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, (25) Filing Language: English PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, (26) Publication Language: English SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: 2014904050 10 October 2014 (10. 10.2014) AU (84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, (71) Applicant: LI-TECHNOLOGY PTY LTD [AU/AU]; GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, Suite 3, 23 Belgravia Street, Belmont, Western Australia TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, 6104 (AU). TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (72) Inventors: JOHNSON, Gary Donald; Suite 3, 23 Bel LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, gravia Steet, Belmont, Western Australia 6104 (AU). SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, URBANI, Mark Daniel; 6 Acastus Rd, Wattle Grove, GW, KM, ML, MR, NE, SN, TD, TG). Western Australia 6107 (AU). VINES, Nicholas John; 13 Nottingham green, High Wycombe, Western Australia Published: 6057 (AU). — with international search report (Art. 21(3)) (74) Agent: WRAYS; 56 Ord Street, West Perth, Western Aus tralia 6005 (AU). (54) Title: RECOVERY PROCESS 00 Figure 1 © v (57) Abstract: A process for the recovery of lithium from lithium bearing mica rich minerals, the process comprising passing an ore o (1) containing one or more lithium bearing mica rich minerals to at least one pre-treatment step (50), passing the pre-treated ore to an acid leach step (60) thereby producing a pregnant leach solution, subjecting the pregnant leach solution to a series of process o steps (80, 140, 160, 180, 200) in which one or more impurity metals are removed, and recovering lithium as a lithium containing salt product (44). "Recovery Process " Field of the Invention [0001] The present invention relates to a process for the recovery of lithium from mica rich minerals. More particularly, the process of the present invention is intended to allow the recovery of lithium, potassium, rubidium, caesium, fluorine and/or aluminium as products from lithium rich mica minerals, including but not limited to lepidolite and zinnwaldite. [0002] The process of the present invention consists of a novel and improved combination of operating steps, one or more of which may have been used previously, in other combinations and for other purposes, in mineral processing and hydrometallurgical processes. Background Art [0003] The major sources of commercially mined Li2C0 3 have historically come from brine solution and spodumene containing ores. To date, there has been no commercial production of Li C03 from lepidolite rich ores or concentrates. Lepidolite is present in many pegmatite deposits, and co-exists with spodumene in some pegmatites. The presence of lepidolite is problematic for refineries that produce Li2C0 3 from spodumene concentrate. As such, the lithium content of lepidolite holds no value and is rejected at the spodumene concentrator. [0004] There have been several efforts to recover lithium from lepidolite in the laboratory and one commercial application. Importantly, none of these prior art efforts have involved direct leaching of the mineral. [0005] A process to extract lithium from lepidolite and produce LiOH is described in US Patent 2,940,820, lodged in 1958. The process was implemented by the American Potash & Chemical Co (operating as American Lithium Chemicals Co) in 1955-1960. Lepidolite was mixed with limestone at a mass ratio of 3:1 then wet ball milled. The discharge from the mill was then filtered and the filter cake was subject to roasting in a rotary kiln at 9 11°C. The discharge was quenched, milled and then leached in a counter-current mixer settler system. Aluminium impurities were precipitated by the addition of lime and the precipitate was removed by filtration. The filtrate was then evaporated to force the crystallisation of LiOH.H20 of relatively low purity. These crystals were purified by re- crystallisation to produce a saleable product. This process relies on low power and limestone costs to be viable, which significantly limits its widespread application. [0006] US Patent 3,189,407 describes a process in which lithium is said to be recovered from low lithium minerals, such as lepidolite, by reaction of the mineral with sulfuric acid and lithium is ultimately precipitated from solution. In this process, lepidolite is first pulped with acid and heated to a temperature of between 140°C and 200°C, preferably 150°C to 170°C (an acid bake) in what is said to be an effort to react only with the lepidolite and not the gangue that may be present. The bake is run over a period of up to 4 hours and only small levels of aluminium and potassium are said to be dissolved. Most of the water present evaporates during the bake, leaving a product substantially in the form of a thick paste, not what might typically be described as a slurry. This paste is then re- pulped in water. Aluminium is then precipitated through the addition of an alkali or alkali earth carbonate to increase the pH to between 3.5 to 4.5. The recovery process of the present invention has as one object thereof to substantially overcome the problems associated with the prior art or to at least provide a useful alternative thereto. [0007] The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia or any other country or region as at the priority date of the application. [0008] Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. [0009] Throughout the specification and claims, unless the context requires otherwise, the word "mica", "micas" or obvious variations thereof will be understood to refer to the group of complex hydrous aluminosilicate minerals that crystallise with a sheet or plate-like structure. Specifically, the mica referred to herein is to be understood to refer to lithium containing mica. Disclosure of the Invention [0010] In accordance with the present invention there is provided a process for the recovery of lithium from lithium bearing mica rich minerals, the process comprising passing an ore containing one or more lithium bearing mica rich minerals to at least one pre-treatment step, passing the pre-treated ore to an acid leach step thereby producing a pregnant leach solution, subjecting the pregnant leach solution to a series of process steps in which one or more impurity metals are removed, and recovering lithium as a lithium containing salt product. [001 1] Preferably, the lithium containing salt is 2CO 3. Additional products may preferably include a potassium containing salt, not limited to but preferably K2S0 4, a rubidium containing salt, not limited to but preferably Rb2S0 4, a caesium containing salt, not limited to but preferably Cs2S0 , a fluorine salt, aluminium as a salt or alumina, and a silica containing product, preferably Na2Si0 3. [0012] Preferably, the fluorine salt comprises a mixture of aluminium fluoride and alumina. Such a mixture is envisaged to be suitable for use as a feed constituent in the electrolytic cells employed in aluminium production, rather than the currently used aluminium fluoride. The aluminium fluoride that is conventionally used is typically prepared by the reaction of aluminium hydroxide with hydrogen fluoride as the mixture added to electrolytic cells must be substantially free from impurities. [0013] Preferably, the mica rich minerals include lepidolite and/or zinnwaldite. [0014] Preferably, the pre-treatment step comprises one or both of a concentration step and a milling step. The milling step may preferably be a fine milling step. The concentration step may be a flotation step. [0015] Still preferably, the milling step produces a product having a particle size of <P8o 1 0 micron. [0016] Still further preferably, the milling step (ii) produces a product having a particle size of <P8o 75 micron. [0017] Preferably, concentrated sulfuric acid is added during the leach step. [0018] Still preferably, the acid leach step results in at least a proportion of the contained lithium, potassium, aluminium, rubidium, fluorine and caesium being extracted into solution, thereby forming the pregnant leach solution ("PLS").