The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.

The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.

The present invention relates to a method of producing lithium hydroxide from a lithium concentrate through sodium sulfate addition and roasting. The method effectively recover lithium ions from the lithium concentrate, minimizes production of byproducts, and produces high-purity lithium hydroxide. By mixing a concentrate containing lithium with sodium sulfate (Na.sub.2SO.sub.4), roasting the concentrate, and leaching the roasted concentrate with water, it is possible to recover lithium ions at a high recovery rate and to produce high-purity lithium hydroxide monohydrate.

The present invention relates to a method of producing lithium hydroxide from a lithium concentrate through sodium sulfate addition and roasting. The method effectively recover lithium ions from the lithium concentrate, minimizes production of byproducts, and produces high-purity lithium hydroxide. By mixing a concentrate containing lithium with sodium sulfate (Na.sub.2SO.sub.4), roasting the concentrate, and leaching the roasted concentrate with water, it is possible to recover lithium ions at a high recovery rate and to produce high-purity lithium hydroxide monohydrate.

Provided are a method and a system for processing a rare earth concentrate ore. The method comprises (1) mixing the rare earth concentrate ore and concentrated sulfuric acid, thereby obtaining a mixed slurry and a first fluorine-containing gas; (2) mixing the mixed slurry and an initiator liquid for acidolysis, thereby obtaining a clinker and a second fluorine-containing gas; (3) subjecting the clinker to leaching with water, thereby obtaining a leached slurry; (4) subjecting the leached slurry to a solid-liquid separation, thereby obtaining a filtrate and a leached slag, and recycling the leached slag to step (2) for acidolysis again.

Provided are a method and a system for processing a rare earth concentrate ore. The method comprises (1) mixing the rare earth concentrate ore and concentrated sulfuric acid, thereby obtaining a mixed slurry and a first fluorine-containing gas; (2) mixing the mixed slurry and an initiator liquid for acidolysis, thereby obtaining a clinker and a second fluorine-containing gas; (3) subjecting the clinker to leaching with water, thereby obtaining a leached slurry; (4) subjecting the leached slurry to a solid-liquid separation, thereby obtaining a filtrate and a leached slag, and recycling the leached slag to step (2) for acidolysis again.

The invention relates to the field of comprehensive recovery of valuable elements such as bromine, base metal and precious metal from incineration ash, especially relates to a method for enriching precious metals from printed circuit board incineration ash by bath smelting-chlorination circulation process. The process mainly comprises pretreatment of the printed circuit board Incineration ash and circulation-chlorination enrichment process for precious metals. The crude copper, crude zinc sulfate, bromine, lead chloride and precious metal enriched slag are obtained. Compared with the traditional process, it realizes the cycle enrichment of precious metals as well as avoids the loss of valuable metals and secondary pollution caused by tail liquid discharge.

The invention relates to the field of comprehensive recovery of valuable elements such as bromine, base metal and precious metal from incineration ash, especially relates to a method for enriching precious metals from printed circuit board incineration ash by bath smelting-chlorination circulation process. The process mainly comprises pretreatment of the printed circuit board Incineration ash and circulation-chlorination enrichment process for precious metals. The crude copper, crude zinc sulfate, bromine, lead chloride and precious metal enriched slag are obtained. Compared with the traditional process, it realizes the cycle enrichment of precious metals as well as avoids the loss of valuable metals and secondary pollution caused by tail liquid discharge.

This invention deals with a system using aqueous means for solubilizing chemical components contained in sulphur type ore concentrate which may contain iron, cobalt, niquel, copper, platinum group metals and other metals considered valuable and of commercial interest. Apart from that, a method using aqueous means for solubilizing such components is described.

The present invention provides a process for metallurgy and separating a rare earth concentrate using a combination method, the process including: treating the rare earth concentrate containing bastnaesite by using a method including roasting under an atmosphere, leaching with hydrochloric acids, and roasting with a sulfuric acid, wherein stepping acid leaching with low-concentration hydrochloric acids is controlled during the leaching with the hydrochloric acids so as to obtain a rare earth solution with a high concentration (150-250 g/L REO), such that a leaching rate of Ce reaches 60% or more, and the content of F.sup.− in a leaching liquor is reduced by aging; and rare earth is further recovered from a leach residue by roasting with the sulfuric acid and leaching with water, and the total yield of the rare earth reaches 95% or more.