Method for preparing alumina and extracting lithium form lithium-rich bauxite waste rock

Abstract

The present invention proposes a method for preparing alumina and extracting lithium from lithium-rich bauxite waste rock, belonging to the field of solid waste comprehensive utilization technology. The method includes crushing and grinding lithium-rich bauxite waste rock, then mixing and stirring with an acid mixture to leach out iron, performing solid-liquid separation to obtain a low-iron filter cake, adding concentrated sulfuric acid to the low-iron filter cake for roasting and ripening, followed by water leaching and hot filtration to obtain filtrate; adding a crystallizing agent to the filtrate, dissolving and evaporating the mixture to obtain steel strip crystals, washing the steel strip crystals with a saturated solution under stirring to remove impurities, performing solid-liquid separation to obtain a lithium-containing solution and low-iron aluminum ammonium sulfate; removing impurities from the lithium-containing solution and precipitating lithium with sodium carbonate to prepare lithium carbonate; and calcining the low-iron ammonium aluminum sulfate to prepare and obtain alumina. The method of the present invention has the advantages of simple process, low energy consumption of aluminum-lithium roasting and leaching, high recovery rate of valuable components of aluminum-lithium, high iron removal rate, high aluminum-lithium separation efficiency, low aluminum-lithium extraction cost, and recyclable crystallizing agent. It is easy to implement in industrialization, greatly improves the comprehensive utilization value of lithium-rich bauxite waste rock.

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