Extraction of lithium from lepidolite using chlorination roasting–water leaching process

Valuable Metals—Recovery Processes, Current Trends, and Recycling Strategies

“…[105] On the other hand, the climatic conditions do not favor facile evaporation. 800 8 8C) is associated with considerable energy consumption, [115] 2) roasting with H 2 SO 4 also requires large amounts of base for precipitation of the hydroxide,a sw ell as the combined by-product Na 2 SO 4 being of very low value because of an over-saturated market, 3) the limestone digestion requires substantial amounts of CaCO 3 .I nf act, the CaCO 3 to ore ratio is 3:1f or lepidolite and even 5:1f or zinnwaldite under optimized conditions. Thebrines are heated by solar power to at emperature that allows for an evaporative concentration of the Li brines under the given wind speed.…”

“…[114] Both methods have significant drawbacks,s ince 1) the hightemperature thermal conversion of a-into b-spodumene (T ! 800 8 8C) is associated with considerable energy consumption, [115] 2) roasting with H 2 SO 4 also requires large amounts of base for precipitation of the hydroxide,a sw ell as the combined by-product Na 2 SO 4 being of very low value because of an over-saturated market, 3) the limestone digestion requires substantial amounts of CaCO 3 .I nf act, the CaCO 3 to ore ratio is 3:1f or lepidolite and even 5:1f or zinnwaldite under optimized conditions. [116] An umber of alternative approaches,p articularly for spodumene,b ut also for petalite,l epidolite,a nd zinnwaldite were more recently developed (summarized in Figure S5 in the Supporting Information).…”

Wertmetalle – Gewinnungsverfahren, aktuelle Trends und Recyclingstrategien

“…Die technisch bedeutendsten Verfahren für die Lithiumgewinnung aus silikatischen Lithiumerzen sind der pyrometallurgische Röstaufschluss mit H 2 SO 4 sowie das Kalksteinbrennen unter Zugabe von CaCO 3 . Beide Verfahren haben erhebliche Nachteile, da 1) der Hochtemperaturprozessschritt zur Phasenumwandlung von α‐ in β‐Spodumen ( T ≥800 °C) einen enormen Energiebedarf erfordert, 2) beim Röstaufschluss mit H 2 SO 4 zudem große Mengen an Base zur Hydroxidfällung benötigt werden sowie das niedrigpreisige Koppelprodukt Na 2 SO 4 wegen der gegebenen Marktübersättigung kaum verkaufsfähig ist, 3) beim Kalksteinbrennen beträchtliche Mengen CaCO 3 benötigt werden, die neben dem Lithiumerz auf Reaktionstemperatur gebracht werden müssen. Beim Lepidolith beträgt das CaCO 3 /Erz‐Verhältnis 3:1, und für Zinnwaldit liegt es im optimierten Prozess bei CaCO 3 /Erz=5:1…”

Lithium Production Processes

“…After roasting lepidolite with a combination of Na 2 SO 4 and CaCl 2 at 880 C, the calcine obtained was then leached with water at ambient temperature to release Li into leach liquor. 47,49,54 Recently, Yan et al 49 roasted a mixture of lepidolite, NaCl, and CaCl 2 at a mass ratio of 1:0.6:0.4 at 880 C for 0.5 h, and then leached the calcine obtained at 60 C for 0.5 h. Using a waterecalcine mass ratio of 2.5:1, approximately 93% Li extraction from lepidolite was realized and a leach liquor containing 3.71 g/L Li was recovered. During purification, Ca was first removed as carbonate by adding soda ash into the leach liquor whereas Mn, Al, and other impurities were subsequently discarded as hydroxides using caustic soda.…”