A kind of extraction system for extracting alkali metal or alkaline earth metal and its application

Abstract

The invention discloses an extraction system for extracting alkaline metals or alkaline-earth metals. The extraction system comprises an extraction agent and a synergistic extraction agent, wherein the extraction agent is a diketone compound, and the synergistic extraction agent is a neutral phosphoric-oxygenic compound. The invention further discloses a method for extracting lithium ions from an alkaline metal solution and extracting alkaline-earth metals from a mixed solution of alkaline metals and alkaline-earth metals through the extraction system. The extraction system has excellent effects for extracting and separating alkaline metals or alkaline-earth metals; and meanwhile, a synergistic extraction agent, ferric trichloride, in the prior art is avoided in the extraction system, so that problems such as high acidity caused by the ferric trichloride and the like can be avoided, the acid dosage and the cost can be reduced, and the corrosion to devices can be reduced as well. After lithium ions or alkaline-earth metal irons are extracted by using the extraction system, the reverse extraction and regeneration processes are simple, and the operation is facilitated.

Description

technical field [0001] The invention belongs to the technical fields of extraction chemistry and chemical industry, and in particular relates to an extraction system for extracting alkali metals or alkaline earth metals and its application. Background technique [0002] Global lithium resources are mainly concentrated in a few countries such as Bolivia, China, Chile, Argentina, Australia, and the United States, and salt lake resources are the main resources. Therefore, extracting lithium from salt lake brine has become the top priority for countries competing for energy strategic heights. China is also one of the countries rich in lithium resources, with reserves accounting for about 10% of the world's total. The proven industrial reserves of lithium resources rank second in the world, second only to Bolivia. Among them, salt lake lithium resources accounted for more than 80%, mainly distributed in Qinghai and Tibet. The prospective reserves of lithium in the salt lake bri...

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Problems solved by technology

But when adopting ferric chloride as the co-extraction agent, there are following problems: (1) the requirement for extraction and separation equipment is relatively high, and the traditional mixing and settling tank is difficult to meet the process requirements, and high-efficiency centrifugal extraction equipment must be used, and the equipment cost is expensive; ( 2) After using ferric chloride, it is very difficult to regenerate the extractant with alkali, and very precise flow control is required, otherwise it will cause problems such as a decrease in extraction rate or emulsification failure of the extractant; (3) due to the co-extraction agent three Ferric chloride can only stably exist in the organic phase when the concentration of chloride ions is higher than 6mol / L, so the extracted feed liquid must be a chloride solution, and an aqueous HCl solution with a concentration of not less than 6mol / L is required during stripping as Stripping agent, the stripping agent has high acidity, large consumption, and serious corrosion to the equipment, so special material extraction equipment must be used; (4) Since the organic phase contains the co-extraction agent ferric chloride, this requires the extraction of the aqueous phase Weak acidity must be maintained, otherwise iron ions will be hydrolyzed. Therefore, the brine that is about to enter the extraction section must be acidified to meet the relative acidity requirements of the extracted water. Lithium and boron are generally associated with each other in Qinghai salt lakes, and boric acid must be precipitated during the acidification process. , need to be filtered

In short, due to the existence of the co-extractant ferric chloride, the extraction process is more complicated, the process control is very difficult, and the investment in equipment is large.

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