CN1093517C

CN1093517C - Lithium salt extraction process from carbonate type bittern

Info

Publication number: CN1093517C
Application number: CN99105828A
Authority: CN
Inventors: 郑绵平; 郭珍旭; 张永生; 杨卉芃; 卜令忠; 李琦; 邓月金; 赵元艺; 张克仁
Original assignee: R&D CENTER FOR SALINE LAKE AND EPITHERMAL DEPOSIT CAGS
Current assignee: R&D CENTER FOR SALINE LAKE AND EPITHERMAL DEPOSIT CAGS
Priority date: 1999-04-20
Filing date: 1999-04-20
Publication date: 2002-10-30
Anticipated expiration: 2019-04-20
Also published as: CN1270927A

Abstract

The present invention provides a method for extracting lithium salts from carbonate type brine, which takes high-lithium and low-sulfate radical brine in a plateau cold-stage lithium salt lake as raw materials; after mixed Li2CO3 salts of which the concentration is 5% are obtained by a salt field technology, lithium concentrates of which the concentration is 68% and the recovery rate is 76% can be separated out by a secondary scrubbing flow by water. CO2 is introduced to convert the Li2CO3 in solution into LiHCO3, and then the solution is heated to enable the Li2CO3 to be precipitated to obtain lithium carbonate products; the byproducts such as boron, potassium, etc. can be recovered. The whole technological flow is simple and advanced and has easy operation; solar energy and cold resources are fully utilized, the consumed energy is little, the consumed materials are few, and the environment can not be polluted, the economic benefit is high.

Description

Lithium salt extraction process from carbonate type bittern

The present invention relates to a kind of extracting method of lithium salts, particularly from the carbonate type salt lake brine, extract the method for Quilonum Retard.

Because the electrochemical activity of lithium is strong, is again light metal, thereby has purposes widely.The demand of lithium is constantly increasing, particularly as the compound Quilonum Retard of lithium.

In world's lithium total resources, bittern lithium ore deposit accounts for 75%, and hard rock lithium ore deposit accounts for 25%, and China bittern lithium ore deposit accounts for 72%, and hard rock lithium ore deposit accounts for 28%.Before the sixties, lithium resource is mainly from hard rock lithium ore.The salt lake carry the lithium cost than the low 1-1.5 of hard rock doubly more than, this forces the industrial development of Chinese lithium must pay attention to putting forward from salt lake brine the method for lithium.It is the best outlet of developing china lithium industry.

Because it is different with the economic technology condition to contain lithium salts lake water chemical type, so the operational path that adopts also has nothing in common with each other.At present in the method for from bittern, carrying lithium, organic ion (TBP, be tributyl phosphate etc.) exchange resin method, inorganic ion exchanger method, aluminate method, hydrogenchloride saltout method and the precipitator method (being phosphate process) and carbon method etc. are arranged.Chinese patent application numbers 941116387 discloses a kind of method of extracting lithium salts from bittern, this method is, with high-carbon hydrochlorate type bittern behind the Exposure to Sunlight pre-concentration, logical carbonic acid gas carries out carbonization, make yellow soda ash change into the sodium bicarbonate precipitation, filter then, behind the further enrichment method lithium of Exposure to Sunlight, add yellow soda ash again, be settled out Quilonum Retard.Its shortcoming is: 1. need to consume a large amount of mineral fuel, get CO in the limestone with burning ₂, Quilonum Retard per ton need consume coal more than 6 tons; 2. its bittern lithium salts rate of recovery lower (about 35%) can not sufficiently and reasonably be utilized local resources; 3. this method is not considered comprehensive utilization.

The object of the present invention is to provide a kind ofly have inconvenient traffic on the plateau, high and cold anoxic and lack area such as fossil energy, utilize natural condition (sun power and cold resource), the power consumption feed consumption is few, and technological operation is simple and easy, the lithium method of carrying from carbonate type bittern of pollution-free and high benefit.

Technical solution of the present invention is:

1. utilize plateau cold conditions of living in to impel Na ₂SO ₄10H ₂The a large amount of sedimentary resources characteristics of O extract the low sulfate radical bittern of high lithium and make raw material from the salt lake;

2. adopting multistage freezing Exposure to Sunlight on-swimmer's pool-control pond-crystallizing pond-mother liquor pond (Fig. 1).Make halite, saltcake separate (evaporation precipitation) in a large number in the shallow pond of Exposure to Sunlight, make lithium in bittern, reach pre-concentration, focus on the control pond then, with the lithium content 1500-2800mg/l of bittern and temperature more than 5 ℃, control is fallen halogen to crystallizing pond, make enrichment higher-grade in the crystallizing pond, high lithium mixed salt that thickness is big, it contains Li ₂CO ₃Grade is more than 5%;

3. use on the spot mud and make salt pan substrate and mud and halite blending and constitute " salt cement concrete ", construct salt pan key facility-water proof earth dyke;

4. adopt clear water to clean the mixed salt novel process, with mixed salt (raw ore)＜10 millimeter (Li ₂CO ₃5% ±) use scrub water I-first road classification-scouring II-second road scouring-classification-dehydration-lithium concentrate, tail washings reclaims.This method can will contain Li ₂CO ₃5% mixed salt (raw ore) sub-elects through secondary scouring flow process and contains Li ₂CO ₃Reach or greater than 68%, the Quilonum Retard concentrate (Fig. 2) of the rate of recovery 76%;

5. the impurity at concentrate comprises water-soluble and solubility in citric acid or sour insoluble characteristics, takes water logging to remove water-soluble salt, then with CO ₂Leach Li ₂CO ₃Carbon soak method, the latter uses LiHCO ₃Solubleness is than Li ₂CO ₃High 3--4 characteristic (Fig. 3) doubly, with concentrate add water-soak except that water-soluble salt class (halite, sylvite and borax etc. are reclaimed in evaporation)-wash thick Li ₂CO ₃, after it is dissolved in water, in solution, feed CO ₂, make the Li in the solution ₂CO ₃Be converted into LiHCO ₃, increase lithium content in the solution:

Solution is heated to 50-150 ℃ then, makes Li ₂CO ₃A large amount of precipitations, CO ₂From solution, overflow (recycling use), obtain finished product Li ₂CO ₃Product.

This cover is put forward the lithium method and is had and suit measures to local conditions, and obtains to contain Li ₂CO ₃Reach 99% high grade Li ₂CO ₃Product, and can comprehensively reclaim salt byproducts such as boron potassium.

Advantage of the present invention is:

At carbonate type lithium salts lake characteristic and plateau Yanhu District nature and economic technology characteristics, suit measures to local conditions, maximize favourable factors and minimize unfavourable ones, by the optimization method of design studies and examination, for finding an economical and effective novel process method in the abundant lithium salts lake of exploitation under high conditions.

1. use novel salt field process, can make full use of the advantage of the climate resources (sun power and cold resource) of nature, make and be easy to dispersive Li in the bittern ₂CO ₃A large amount of concentrate precipitation and extract, and reduce cost to greatest extent and reduce the consumption of mineral fuel.

2. utilization scouring method is from mixed salt (raw ore) sorting Li ₂CO ₃Concentrate is the sorting agent with the most cheap Freshwater resources, replaces flotation agent such as coco amine, obtains at the scene to contain higher-grade (more than 68%) Li ₂CO ₃Concentrate not only reduces the sorting cost significantly, has avoided little poisonous substance matter contaminate environment, and reduces long-distance useless transportation in a large number.

3. comprise water-soluble and solubility in citric acid or sour insoluble characteristics at selecting the concentrate impurities, take carbon to soak the method novel process.

This cover is put forward the lithium method and is had to suit measures to local conditions to obtain and contain Li ₂CO ₃Reach 99% high grade Li ₂CO ₃Product, and have the practicality and the advance of salts such as comprehensive recovery boron potassium.

4. make " salt cement concrete " with local mud and construct water proof materials such as water proof earth dyke substituted type plastic film, can save a large amount of expenses of building the big area salt pan.

Description of drawings

Fig. 1. be salt pan of the present invention sinker flow sheet

Fig. 2. be the present invention's scouring-grading technology schema

Fig. 3. for carbon of the present invention soaks method purification schemes figure

The rich caesium bromine of the rich potassium boron of the high lithium mixed salt of 1-1 halite sodium chloride crystal section .1-2 halite crystallized region .2. crystallized region .3. mixed salt crystallized region .4. potassium boron mother liquor among Fig. 1

Implementation result: at carbonate type lithium salts lake, as novel type lithium salts lake, Zha Buye lake, Tibet, according to technical scheme of the present invention, the implementation result of obtaining sees Table 1.

Table 1 implementation result table

The name of an article	Contain Li ₂CO ₃(％)	Quantity (kg)	Rate of recovery %	Remarks
The name of an article	Contain Li ₂CO ₃(％)	Quantity (kg)	Rate of recovery %	Remarks	Mixed salt	4.5-5.2	65000	70	Pilot scale
Concentrate	65-70	2100	76	Pilot scale	Mixed salt	4.5-5.2	65000	70	Pilot scale
Concentrate	65-70	2100	76	Pilot scale	Product	98-99	100	96	Finish lab scale, just set about pilot scale

Claims

1. from carbonate type bittern, extract the method for Quilonum Retard, it is characterized in that:

(1). utilize salt lake, plateau cold conditions of living in to impel Na ₂SO ₄10H ₂O precipitates in a large number, extracts the low sulfate radical bittern of high lithium and makes raw material;

(2). raw brine is sent into multistage freezing Exposure to Sunlight on-swimmer's pool earlier, freezing Exposure to Sunlight, after enter the control pond, controlled temperature more than 5 ℃, the lithium content of bittern is at 1500-2800mg/l, sends into the crystallizing pond crystallization again, can obtain Li ₂CO ₃Content is at the high lithium mixed salt more than 5%;

(3). high lithium mixed salt through the clear water secondary clean, classification, dewater afterwards lithium concentrate;

(4). remove water soluble salt in the lithium concentrate with water logging, halite, sylvite and borax are reclaimed in evaporation, wash thick Li ₂CO ₃, be dissolved in water again, in solution, feed CO ₂, make Li ₂CO ₃Become LiHCO ₃,, make LiHCO by thermolysis ₃Become Li ₂CO ₃

2. the method for extracting Quilonum Retard from carbonate type bittern according to claim 1 is characterized in that, uses the mud on the spot of fusion halite to construct salt pan water proof earth dyke.

3. the method for extracting Quilonum Retard from carbonate type bittern according to claim 1 is characterized in that described heat decomposition temperature is at 50-150 ℃.