Method for producing refined lithium sulfate solution used in lepidolite lithium-extracting technique by sulfuric acid process

Abstract

Provided is a process for producing refined lithium sulfate solution of lepidolite lithium extracting technology with sulfuric acid process, which takes lepidolite clean ore as raw material and sequentially includes the following steps, including leaching, alum cooling and decanting, acid removing, aluminum removing, decontaminating and deliming, thereby achieving refined lithium sulfate solution. The alum cooling and decanting process of the invention can precipitate kalium, rubidium and caesium in alum form, thereby the separation of lithium and kalium, rubidium and caesium is easily achieved, and the achieved alum dregs of kalium, rubidium and caesium are blend alum with high purity, which creates perfect condition for comprehensive utilization and simultaneously reduces the burdens of the separation of lithium and aluminum. The aluminum removing process can easily achieve the separation of lithium and aluminum. The process of the invention has the advantages that the energy consumption is relatively low, and the lithium yield is relatively high, most of the residues can be used and the process is favorable for comprehensive utilization. The invention further provides a process for producing lithium carbonate and lithium fluoride with the achieved refined lithium sulfate solution.

Description

technical field [0001] The invention belongs to a method for extracting lithium from lepidolite, in particular to a method for producing refined lithium sulfate solution in the early stage in the process of extracting lithium from lepidolite ore by a sulfuric acid method. Background technique [0002] There are about 145 kinds of lithium-containing minerals, and spodumene (Li 2 O·Al 2 o 3 4SiO2 2 ), lepidolite KLi 1.5 Al 1.5 [AlSi 3 o 10 ] (OH, F) 2 , Lithium feldspar (Li 2 O·Al 2 o 3 ·8SiO2 2 ), iron lepidolite K (Li, Fe 2+ , Al)[AlSi 3 o 10 ] (OH, F) 2 and phospholithium mica LiAl[PO 4 ] (F, OH). Salt lake brine is now the most important lithium refining resource. Before lithium extraction from brine, the world’s lithium was mainly extracted from ore. Later, due to the low cost of lithium extraction from brine, there are few manufacturers in the world that extract lithium from ore. However, due to The demand for lithium has increased, and the price of its ...

AI Technical Summary

Problems solved by technology

The disadvantages of the lime method are high energy consumption, unusable slag and low yield

The disadvantage of the chlorination method is that the corrosion of the equipment is particularly serious, and the slag cannot be used

The disadvantages of the sulfate method are relatively high energy consumption, unusable slag, high cost, and expensive rubidium and cesium left in the slag

[0004] In the process of extracting lithium from lepidolite ore by sulfuric acid method, sulfuric acid is generally used to react with lepidolite, lithium is leached from lepidolite into liquid phase lithium sulfate, and refined lithium sulfate solution is prepared through the coarsening process. Lithium is extracted from the refined lithium sulfate solution. The existing method for preparing the refined lithium sulfate solution also has the problems of high energy consumption, unusable slag, high cost, and expensive gold is easy to stay in the slag.

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