Method and system for purification and concentration of lithium-containing desorbed solution in alumina plant

Abstract

The invention discloses a method and system for purification and concentration of a lithium-containing desorbed solution in an alumina plant. The method includes: adding an inorganic acid into the lithium-containing desorbed solution, conducting stirring neutralization, controlling the mixed solution weak alkalinity, pouring the mixed solution into a clarifying tank for standing, overflowing the supernatant for standby use, subjecting the supernatant to heat exchange cooling to a temperature below 35DEG C, then subjecting the cooled supernatant to treatment in a membrane separation unit, sending the dilute liquid subjected to membrane separation treatment back to the alumina plant for recycling, and using the thick solution as the lithium-containing purified concentrated solution. The system includes a neutralization tank, a clarification overflow component, a heat exchanger and a membrane separation component. The membrane separation component includes a membrane separation treatmentunit, a dilute liquid tank, a thick liquid tank and a third centrifugal pump. The invention adopts acid-base neutralization and membrane separation for purification and concentration, and the processis concise and efficient; the concentrating multiple is higher than 16 times, the energy consumption and operation cost are low, the lithium recovery rate is greater than or equal to 90%, and Li<+> inED produced concentrated water is more than or equal to 8g / l, thus creating conditions for subsequent production of high-quality lithium carbonate.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry, and relates to a method for extracting high value-added lithium salt from the semen of alumina produced by Bayer method or sintering method, in particular to a method and system for purifying lithium-containing analytical solution in concentrated alumina factories . Background technique [0002] Lithium carbonate, an inorganic compound with the formula Li 2 CO 3 , as colorless monoclinic crystals or white powder. Density 2.11g / cm3, melting point 618℃, soluble in dilute acid, slightly soluble in water, higher solubility in cold water than hot water, insoluble in alcohol and acetone. Widely used in batteries, ceramic glass, lubricants, pharmaceuticals and other industries. [0003] Lithium carbonate is the basic material for the production of secondary lithium salts and lithium metal products, so it has become the most used lithium product in the lithium industry, and other ...

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Problems solved by technology

[0011] It can be seen from Table 1 that Li in the products of alumina factories in central my country 2 O is generally high, usually imported alumina Li 2 O is only 0.006%. If it is estimated at 0.1%, the alumina production is estimated at 12 million tons / year, and the Li 2 O is as high as 12,000 tons. These lithium resources have not been rationally utilized. What's more, the lithium enrichment in the electrolyte of the electrolysis plant that uses lithium-rich alumina as raw material for a long time exceeds a reasonable range, which leads to the deterioration of the working conditions of the electrolysis cell, which in turn has to be limited Lithium-rich alumina

[0012] After checking the relevant literature at home and abroad, there is no report on the purification of lithium-containing analytical solution in concentrated alumina plants

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