Method for preparing lithium carbonate by using acid-resistant membrane

Abstract

The invention discloses a method for preparing lithium carbonate by using an acid-resistant membrane. The method comprises the following steps: S01, concentrating a lithium-rich solution I by using areverse osmosis membrane to obtain a lithium-rich solution II; S02, filtering the lithium-rich solution II through a nanofiltration membrane to obtain a lithium-rich solution III; S03, adding a pH regulator into the lithium-rich solution III, and regulating the pH to 5-9 to obtain a lithium-rich solution IV; S04, filtering the lithium-rich solution IV through ion exchange resin to obtain a lithium-rich solution V; S05, concentrating the lithium-rich solution V through a high-pressure reverse osmosis membrane to obtain a lithium-rich solution VI; and S06, adding sodium carbonate into the lithium-rich solution VI to separate out lithium carbonate crystals. According to the method for preparing the lithium carbonate by utilizing the acid-resistant membrane, the problems of concentration and impurity removal of the lithium-rich solution are solved through the acid-resistant membrane, the additive amount of a medicament can be greatly reduced, and impurity introduction is reduced.

Description

technical field [0001] The invention relates to the field of lithium ion purification, in particular to a method for preparing lithium carbonate by using an acid-resistant membrane. Background technique [0002] Lithium is the lightest metal element in nature, and it ranks the first among group IA alkali metals in the periodic table, and is the lightest and most active alkali metal. Because of its wide range of applications, it is known as "industrial monosodium glutamate"; and because lithium has the highest standard oxidation potential among various elements, it is the undisputed best element in the field of batteries and power supplies, so it is also called "energy metal". ". [0003] According to different raw materials, the lithium extraction process can be divided into two process routes: ore lithium extraction and brine lithium extraction. Lithium extraction from ore is the earliest process route adopted. Due to the small total reserves of lithium in ore and high en...

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Problems solved by technology

[0004] Salt lakes in Qinghai, Tibet and other places contain relatively high lithium content. Among the current lithium extraction methods, the solar pond method is mainly used for industrial lithium extraction in Tibetan salt lakes. This method has a long production cycle from salt lake brine to lithium resource products, and usually requires It takes a long time to make statistics in units of years, which seriously affects the efficiency of lithium extraction

Qinghai Salt Lake mainly uses the aluminum-based adsorption method for industrial lithium extraction. This method requires pretreatment such as heating up the brine of the salt lake. For high-altitude and low-temperature environments, pretreatment such as heating will inevitably increase more power consumption. The concentration of the lithium-containing solution is low, and a multi-step purification process is required in the follow-up, which makes the entire extraction process time-consuming and labor-intensive

[0005] At the same time, there are many metal impurity ions in the lithium-rich solution extracted from salt lake brine. In order to change the lithium-rich solution into lithium carbonate, it is necessary to add a variety of precipitants or impurities-extracting agents to remove impurity ions. This process is cumbersome and time-consuming. And cannot guarantee the output of final lithium carbonate

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