Method for extracting lithium salt from salt lake bittern with low-magnesium-lithium ratio with calcium circulation solid phase conversion method

Abstract

The invention relates to a method for extracting lithium salts from saline salt brine with a low magnesium-lithium ratio through a calcium cycling solid-phase conversion method. The method is to take the saline salt brine with the low magnesium-lithium ratio as a raw material and adopt the technological flows of brine concentration, magnesium and sulfur removal through lime cream, calcium separation through lithium carbonate, lithium extraction through sodium carbonate, thermal decomposition of calcium carbonate, hydration of quicklime into cream, and the like to extract lithium carbonate products. The main technical points of the method comprises that: the method is based on a solid-phase conversion principle of anions (OH, CO3) and realizes magnesium and calcium removal of the brine, purification of the lithium salts and closed cycle of calcium through solid-phase conversion of Ca(OH)2, Mg(OH)2, Li2CO3, Ca(OH)2, CaCO3, CaO, Ca(OH)2. The method comprehensively utilizes magnesium resources and lithium resources of saline lakes, has the characteristics of high magnesium removal efficiency, good purification effect of the lithium salts, high recovery rate of lithium and magnesium, low energy consumption, low cost, closed cycle of the calcium, small project investment, and the like, and is particularly suitable for industrial production on a large scale. In addition, the whole process is simple, clean and environment-friendly.

Description

technical field

[0001] The invention belongs to the field of nonferrous metal metallurgy, and in particular relates to a process for extracting lithium salt from salt lake brine, in particular to a method for extracting lithium salt from salt lake brine with a low magnesium-to-lithium ratio. Background technique

[0002] Lithium is an important non-ferrous metal, known as "the energy metal of the 21st century". It is widely used in many high-tech fields such as energy and aviation, and occupies an extremely important position in the global economy. Global lithium resources can be divided into five types, namely pegmatite lithium, brine lithium, seawater lithium, hot spring lithium, and accumulated lithium ore. Currently, the lithium resources mined and utilized are mainly pegmatite lithium ore and brine lithium ore. Most of the current global lithium consumption comes from lithium brine mines.

[0003] At present, the key technology for extracting lithium from salt lake bri...

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