Device applied to separation and recovery of carbonate in salt lake water

Abstract

The invention provides a device applied to separation and recovery of carbonate in salt lake water, and belongs to the technical field of compound separation and collection, and the device is characterized in that an ultrafiltration unit is used for filtering a to-be-treated solution containing carbonate to obtain ultrafiltration produced water; the first nanofiltration separation unit is used for obtaining first nanofiltration concentrated water and first nanofiltration produced water; the first reverse osmosis unit is used for treating the first reverse osmosis produced water to obtain first reverse osmosis concentrated water and first reverse osmosis produced water; the second nanofiltration separation unit is used for obtaining secondary nanofiltration concentrated water and secondary nanofiltration produced water; the second reverse osmosis unit is used for primarily concentrating disodium produced water; the concentration unit is used for concentrating the second reverse osmosis concentrated water to obtain a lithium-rich solution; the third nanofiltration separation unit is used for carrying out carbonate separation and concentration on the primary nanofiltration concentrated water; and the salt pan process unit is used for evaporating, concentrating, cooling and crystallizing the Sansodium concentrated water. The carbonate separation and recovery device disclosed by the invention is high in production efficiency, low in cost, recyclable in resource and less in environmental pollution; the pollution of the ultrafiltration membrane and the nanofiltration membrane can be relieved through short-process ultrafiltration, and efficient recycling of salt lake resources is achieved.

Description

technical field [0001] The invention relates to the technical field of compound separation and collection, in particular to a device and method applicable to the separation and recovery of carbonates in salt lake water. Background technique [0002] The main techniques of traditional salt lake lithium extraction include adsorption method, membrane method, salt pan concentration and precipitation method, solar pond technology and solvent extraction method, each of which has different advantages and disadvantages. [0003] Carbonic acid salt lakes are characterized by high lithium, magnesium deficiency, and rich lithium carbonate. The brine is close to or reaches the saturation point of lithium carbonate, and it is easy to form different forms of natural lithium carbonate deposits. Most of them rely on the local abundant solar and wind energy resources to develop lithium by brine. , the whole process does not need to add chemical reagents, and only relies on solar energy and w...

AI Technical Summary

Problems solved by technology

[0009] The limitations of Yantian process: 1) Long production time, weak capacity adjustment ability; greatly affected by climate conditions

2) High lithium loss rate and low recovery rate

At present, the average recovery rate of lithium in salt fields in South America is lower than 35%. The low recovery rate means an indirect increase in the actual cost of the project; superimposing the negative impact of brine dilution caused by poor tail liquid treatment, there is a certain degree of waste of lithium resources

[0010] Technical limitations of solar pools: 1) Winter halogen Li + high content of CO 3 2- Low content, Li + The precipitation is incomplete, resulting in a low overall precipitation rate of lithium carbonate, and the loss of lithium in the tail brine discharged after lithium sinking is serious

2) In actual production, due to CO 3 2- In the process of evaporation and concentration of brine, lithium salts are easy to crystallize in segments, and the precipitation is relatively dispersed, which is not conducive to the extraction and processing of lithium salts

3) The brine making process is susceptible to seasonal temperature interference, and only April to October is the operating time of the solar pond, the effective production time is short, and the output is limited

[0011] Limitations of membrane technology: 1) Membrane technology has high requirements on influent water quality, membrane quality, and performance. At present, the pretreatment link of nanofiltration separation technology has not attracted much attention. Traditional pretreatment such as multi-media filter and ultrafiltration The treatment effect of the method is not ideal in actual application, which leads to the failure of the water quality to reach the design value, resulting in a short service life of the separation membrane, rapid wear of downstream equipment, and high maintenance costs, which further increase the cost per ton

However, other resources on the concentrated water side, such as carbonate, have not been effectively recycled. In actual production, the additional purchase of sodium carbonate agent required for lithium precipitation increases production costs.

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