Analytical method of lithium manganate series adsorbent precursors

Abstract

The invention discloses a method for desorption of a lithium manganate series adsorbent precursor and belongs to the field of inorganic salt separation and purification. Before the absorption-desorption cycle starts, inhibitor is added quantitatively to the adsorbent precursor. After the cycle starts, the first time of desorption is conducted on the lithium manganate series adsorbent precursor adsorbing lithium-ions with the second time of desorption solution of the last round, filtrate obtained after filtration is subjected to pH regulation and then directly concentrated to produce lithium carbonate, filtered solid adsorbent (containing incompletely desorbed adsorbent precursor) is added to newly prepared sulfuric acid for the second time of desorption, and filtrate obtained after filtration is used for the first time of desorption of the next round. The method can be used for separation and extraction of lithium from salt lake brine with a high ratio of magnesium to lithium, loss of adsorbent is effectively prevented, the concentration of lithium-ions in desorption solution is increased through desorption, and concentration cost is reduced for lithium carbonate production.

Description

[0001] Technical field: [0002] The invention belongs to the technical field of separation and purification of inorganic salts in the fields of chemistry and chemical industry, and in particular relates to a method for analyzing lithium manganate series adsorbent precursors. [0003] Background technique: [0004] Lithium and its compounds are widely used in various fields of the national economy, especially for the promotion of new energy vehicles. The demand for lithium is increasing year by year. At present, lithium ore resources are of low grade, insufficient supply, and high production costs. and other factors. Lithium resources are abundant in the salt lake brines of Qinghai, Tibet, and Xinjiang in my country, accounting for 87% of the total reserves. However, due to the high ratio of magnesium to lithium in salt lake brine, the high mining cost is difficult to develop and utilize on a large scale. Therefore, an economical and efficient method is explored. The method of ...

AI Technical Summary

Problems solved by technology

Lithium resources are abundant in the salt lake brines of Qinghai, Tibet, and Xinjiang in my country, accounting for 87% of the total reserves. However, due to the high ratio of magnesium to lithium in salt lake brine, the high mining cost is difficult to develop and utilize on a large scale. Therefore, an economical and efficient method is explored. The method of extracting lithium from salt lake brine has important strategic significance and positive guiding significance

[0005] At present, there are two methods for extracting lithium from salt lake brine: one is the adsorption method. Qinghai Salt Lake Group introduced Russian technology and used aluminum-based adsorbents to extract lithium. After nearly four years of operation, the main problem is that the adsorbent has low adsorption capacity ( 1-3mg / g), the concentration of lithium ions in the analysis solution is low (30-80mg / L), the cost of washing and concentration is high, and it is difficult to have good economic benefits

The second is that Qinghai Lithium Industry and Qinghai CITIC Guoan Company use membrane separation or nanofiltration to separate magnesium and lithium. Since the operation, there are disadvantages such as short service life of the membrane and low lithium ion concentration (50-100mg / L), which cannot be used for a long time and the benefits are not good.

However, they mainly focused on the synthesis of the adsorbent precursor, and the analysis of the precursor stayed in the simple length of time, the dissolution loss during the analysis, and the concentration of lithium ions in the analysis solution were not explored in depth, so the adsorption The service life of the agent and the cost of concentration are limited

Yang Xiaojuan from Beijing Normal University once compared the analytical dissolution loss of precursors. When a certain concentration of hydrochloric acid was directly used as the analytical solution, the single dissolution rate of manganese was as high as 26%. Ammonium persulfate solution (0.5 mol / L) was used as the Analyzing solution, the temperature is maintained at 60 degrees for 6 hours, the single dissolution rate of manganese is only 0.045% (Journal of Beijing Normal University, 46 (2010): 49-51), ammonium persulfate can well inhibit the loss of adsorbent, but The consumption of ammonium persulfate is large, the analysis temperature is high and the time is long

Li was reported abroad 1.33 mn 1.67 o 4 The single dissolution loss rate is about 3.5% (Ind. Eng. Chem. Res. 2002, 41, 4281-4287). In all these reports, the concentration of lithium ions released is below 1g / L, which is not conducive to subsequent concentration Shen Li

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