Novel method for preparing battery grade lithium carbonate by using tantalum niobium tailings lithium mica

Abstract

The invention provides a novel method for preparing battery grade lithium carbonate by using tantalum niobium tailings lithium mica. The method is characterized by comprising the following steps of: crushing lithium mica powder until granularity is 100 to 200 meshes, adding the crushed lithium mica powder and 30 to 70 percent sulfuric acid solution in a solid and liquid mass ratio of 1:(2-8) into a reaction device, reacting at the temperature of between 60 and 200 DEG C for 3 to 10 hours to obtain the sulfuric acid solution which contains Li<+>, and separating to remove fluorine-containing solution; performing filtering separation on the sulfuric acid solution which contains the Li<+>, and fully washing the filter residue with water to remove the filter residue and obtain filtrate which serves as mother liquor 1; changing the temperature of the mother liquor to be between 10 and 100 DEG C with stirring, separating solids, namely rubidium, caesium and alum, performing filtering separation, washing the filter residue, and recovering the filtrate as mother liquor 2; adding calcium hydroxide into the mother liquor 2, and controlling the pH value of the solution to between 2 and 7 to obtain solid and liquid mixed solution of neutralization reaction; performing filtering separation on the solid and liquid mixed solution, washing and filtering the filter residue, and recovering the filtrate as mother liquor 3; performing evaporation concentration on the mother liquor 3, controlling the concentration of the Li<+> in the solution to be between 40 and 65g/l, and filtering to obtain the filtrate serving as mother liquor 4; and blowing carbon dioxide into the mother liquor 4 at the temperature of between 95 and 105 DEG C under 2 atmospheres and performing lithium-sinking reaction for 40 to 100 minutes, filtering and mechanically separating to obtain lithium carbonate, washing with water, and drying to obtain the battery grade lithium carbonate product.

Description

technical field [0001] The invention belongs to the field of chemistry and chemical engineering, and relates to a new method for preparing battery-grade lithium carbonate by utilizing tantalum-niobium tailings lepidolite. Background technique [0002] The tantalum-niobium-lithium mine in Yichun, Jiangxi is currently the largest tantalum-niobium-lithium mine in Asia. It contains rich rare metal materials such as tantalum, niobium, lithium, potassium, sodium, rubidium, and cesium. Lepidolite is a by-product obtained by flotation of tantalum and niobium mining tailings. Lepidolite is not only Li 2 The content of O is as high as 4.5%, and the content of potassium, aluminum, and sodium is about 9%. Its comprehensive development and utilization has very important economic and strategic value. [0003] Lithium carbonate is an important chemical raw material. With the national new energy development plan, lithium battery new energy is one of the key energy industries supported by t...

AI Technical Summary

Problems solved by technology

At present, the preparation methods of lithium carbonate mainly include solid ore and liquid ore in terms of raw materials. The liquid ore is mainly extracted from salt lake brine. This method is easy to extract and mature because of its low raw material cost. The ion content is high, and it is easier to produce industrial-grade lithium carbonate, but it is very difficult to produce battery-grade lithium carbonate, and the production cost is high. The second is to use ore as raw material, mainly lepidolite and spodumene as raw materials for extraction. The extraction method is the sulfuric acid method or potassium sulfate and limestone sintering method. Because the limestone calcination method adopts high-temperature calcination, the temperature is generally about 1000 ° C, so the energy consumption is high, the material flow is large, the lithium recovery rate is low, and the product cost is high. The loss of cesium and rubidium in the extraction of lepidolite from the tantalum-niobium-lithium mine in Yichun, Jiangxi is high, the extraction rate is low, the resources cannot be fully utilized, and the advantages and value of comprehensive development cannot be fully reflected

[0004] The sulfuric acid method adopts concentrated sulfuric acid and lepidolite ore to be roasted at high temperature, and the lithium carbonate root is precipitated, which also has high energy consumption and has a great impact on environmental pollution. Lepidolite is used as raw material, and it is extracted by calcination, which leads to a large waste of energy, large investment in equipment, and discharge of three wastes, especially waste gas, which puts a great pressure on the environment

Another example is the "Potassium Sulfate Process to Process Lepidolite to Produce Potassium Carbonate" (National Invention Patent ZL85101989), which is to mix potassium sulfate and lepidolite according to the proportion and then roast at a high temperature for 2 hours at 930°C, and then roast the roasted material Carry out two-stage four-stage leaching process to extract lithium carbonate products. This method still adopts high-temperature roasting process, which wastes a lot of energy and causes pollution to the environment.