Lepidolite to Lithium Conversion., page-105

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Method for extracting lithium carbonate from lepidolite raw material and removing aluminium
CN 102225774 A
ABSTRACT
The invention discloses a method for extracting lithium carbonate from a lepidolite raw material and removing aluminium, which comprises the following process steps: (1) fluorine removal by reaction, that is, soaking lepidolite powder with a sulfuric acid solution for reaction to remove fluorine so as to obtain a solid-liquid mixed solution; (2) separation and refrigeration processing, that is, filtering the mixed solution, separating to remove filter residues to obtain a filtrate mother liquor 1, controlling the mother liquor 1 to obtain a K+ and Al3+ saturated solution, performing refrigeration, cooling, filtration, and separation, removing residues to obtain a filtrate mother liquor 2; (3) neutralization for aluminium removal, that is, cooling and refrigerating the mother liquor 2, filtering and separating to obtain a filtrate solution, adding a divalent metal oxide to obtain a mother liquor 3, precipitating and filtering the mother liquor 3 to remove residues, separating to obtain a mother liquor 4; (4) filtration and concentration to prepare a product, that is, concentrating the mother liquor 4, filtering, adding a sodium carbonate solution into the filtrate for reaction, filtering and separating, recovering the filtrate, wherein the filter residue is lithium carbonate. The extraction of lithium carbonate from a lepidolite raw material has a high aluminium-removing rate and low energy consumption, improves the yield of lithium carbonate, has a high recovery utilization rate of aluminium, and therefore the production cost is decreased greatly.
CLAIMS(5)  translated from Chinese
A method for extracting lithium from lepidolite feedstock except aluminum, comprising the process steps: (1) the reaction fluorine, lithium will 80-300 purpose Mica placed in a reaction apparatus, impregnated with sulfuric acid solution at 100 ~ 130 ° C reaction temperature 4~10 hours, separation and removal, solid-liquid mixture obtained solution; (2) separating the freezing process, the mixed solution was separated by filtration to remove residue, have to filtrate liquor 1, the control liquor 1 is K +, Al3 + saturated solution, cooled to freezing 0~40 ° C and then separated by filtration, slag, and the filtrate mother liquor was 2; (3) and, in addition to aluminum, the mother liquor was stirred and cooled freeze 2 to 0~-30 ° C, separated by filtration , filtrate solution was added thereto to give a divalent metal oxide or hydroxide is formed mother liquor 3, the precipitate was filtered liquor dregs 3, and controls the Al3 + concentration in the filtrate <0. 008 g / Ι, the mother liquor was separated by filtration to obtain 4; (4) filtered concentrated mother liquor was concentrated and the control solution, 4 Li + concentration 20~45 g / Ι, then filtered and the reaction solution was added sodium carbonate in the filtrate was separated by filtration, the filtrate was recovered, i.e., lithium carbonate residue.
2. according to claim extract lithium from lepidolite feed 1 except aluminum method and other symptoms is the concentration of the sulfuric acid solution is 40~60Wt%, mass ratio of lepidolite and sulfuric acid solution is 1: 2- 4.
3. according to claim extract lithium from lepidolite feed 1 except aluminum method and other symptoms is the step (2) was added to the mother liquor 1 Al2 (SO4) 3 or Al (OH) 3, so liquor 1 K +, Al3 + concentration is saturated to form a saturated solution.
Extracting lithium from lepidolite feedstock according to claim 4. In addition to aluminum based method and other symptoms is the divalent metal oxide or hydroxide is calcium oxide or calcium hydroxide.
Extracting lithium from lepidolite feed 1 according to claim 5 wherein the aluminum removal method, which is to control symptoms such as (2) quality of each step chemical residues than the content of component Li2O 0. 55-0. 62 %, K2O 0.9-1.08%, Na2O 0. 4-0. 45%, Al2O3 8-8. 01%, SiO2 88. 9-89. 74%, Rb2O 0. 11-0. 123%, CS2O 0. 015 -0. 018%.
DESCRIPTION  translated from Chinese
The method of extracting lithium from lepidolite feedstock except aluminum
[0001] TECHNICAL FIELD: The present invention relates to a method other raw materials from lepidolite aluminum, in addition to aluminum lithium carbonate extraction, especially from lepidolite feedstock.
[0002] BACKGROUND: lepidolite is an important mineral resources, which is rich in rare metal materials, such as lithium, sodium, potassium, rubidium, cesium, and aluminum. Jiangxi Yichun lithium niobium tantalum ore is Asia's largest lithium niobium tantalum ore, lepidolite Li2O content of the raw material reaches 4.5% alumina content of about 23%, its comprehensive development and utilization has very important economic and strategic value.
[0003] With the increasingly tense world energy, particularly petroleum-based raw materials, increasing energy shortage, development and utilization of new energy for the common task of the world. Lithium New Energy as an important industry in today's new energy development, more and more countries are seriously, lithium carbonate as the lithium new energy industry base material, with great prospects for development.
[0004] The method is currently extracted from lepidolite lithium carbonate raw materials, from raw material point of view there solid and liquid mine ore, ore mainly liquid salt lake water as raw material extraction, solid mine ore as raw material is mainly lithium mica or spodumene as raw material for the extraction, using the high-temperature calcination temperature is typically at about 1000 ° c, and other chemical methods such as sulfuric acid dipping. Solid ore as raw material way, regardless of calcination or chemical methods must lepidolite feedstock for removing aluminum and recycled to extract lithium carbonate from the existing lepidolite feed production process, in addition to aluminum is adopted Simple freezing treatment, then centrifuged compound solution of aluminum that is removed. This method is only a preliminary solution to remove aluminum ions, which greatly affect the yield of lithium carbonate, and even cause the success of the extraction process, to extract lithium carbonate content is not high. There is mica calcined lithium aluminum removal. Aluminum recycling difficult, a waste of resources, but also through high-temperature calcination, energy consumption is also large.
[0005] SUMMARY: The purpose of the present invention is to provide an extract lithium from lepidolite except aluminum feedstock methods to extract lithium carbonate, lithium mica as raw aluminum removal rate, energy consumption, improve the system of lithium carbonate The yield and aluminum recycling rates high, thus significantly reducing its production costs.
[0006] The aspect of the present invention is to achieve, including the following process steps:
(1) reaction of fluorine, lithium will 80-300 purpose Mica placed in a reaction apparatus, was impregnated with sulfuric acid in the reaction 4~10 hours 100~ 130 ° C temperature separation and removal, solid-liquid mixture to obtain a solution;
(2) separating the freezing treatment, the mixed solution was separated by filtration to remove the residue to obtain a filtrate mother liquor, the mother liquor control 1 K +, Al3 + saturated solution, cooled to freezing 0~40 ° C and then separated by filtration, the filtrate mother liquor was Cleaner 2 ;
(3) and in addition to the move, the mother liquor 2 stirred and cooled to freezing 0~-30 ° C, separated by filtration, the filtrate was added to a solution of divalent metal oxide or hydroxide is formed and mother liquor 3, the mother liquor 3 precipitate Cleaner filtered and the filtrate control Al3 + concentration <0. 008 g / Ι, separated by filtration to obtain liquor 4;
(4) filtered and concentrated molded product, the mother liquor was concentrated and the control solution, 4 Li + concentration 20~45 g / Ι, then filtered and the reaction solution was added sodium carbonate in the filtrate was separated by filtration, the filtrate was recovered, i.e., lithium carbonate residue.
The [0007] The present invention is a solution of sulfuric acid concentration is preferably 40~60Wt%, lepidolite and sulfuric acid solution mass ratio of 1: 2-4.
[0008] The steps of the present invention (2) is added Al2 (SO4) 3 or Al (OH) 3 to liquor 1, mother liquor 1 K +, Al3 + concentration is saturated form K +, Al3 + saturated solution.
[0009] The present invention is a divalent metal oxide or hydroxide is preferably calcium oxide or calcium hydroxide.
[0010] The present invention control (2) the quality of each step chemical residues than the content of component Li2O 0. 55-0. 62%, K2O0. 9-1. 08%, Na2O 0. 4-0. 45%, Al2O3 8-8. 01%, SiO2 88. 9-89. 74%, Rb2O 0. 11-0. 123%, CS2O 0.015-0. 018%.
Method [0011] The present invention is extracted from lepidolite addition to aluminum lithium carbonate raw materials, the use of the process of leaching to extract lithium carbonate raw materials lepidolite low-temperature acid, by freezing the divided precipitate the lithium aluminum step, the aluminum leaching solution cleanly removed, a substantial increase in the lithium carbonate content and yield, improved product quality, product of I ^ b + Zn + Al content of less than 0.0008%, lower production cost, process conditions are mild, stable operation, short production cycle, high capacity utilization, less waste discharge, thus greatly improving the overall economic efficiency of lepidolite, and small environmental waste emissions.
[0012] The method of the present invention has been tested and produced lithium carbonate purity of more than 99.5%, the technical indicators are shown in Table 1

The production process of the present invention, the main chemical reactions involved in the equation:
Li2CHH2SO4 - Li2S04 + H20 K2CHH2SO4 - K2S04 + H20 Na20 + H2S04 - Na2S04 + H20 A1203 + 3H2S04 - AL2 (SO4) 3 + 3H20 Rb203 + 3H2S04 - Rb2 (SO4) 3 + 3H20 Cs20 + H2S04 - Cs2S04 + H20 Li2S04 + Ca ( OH) 2 - 2Li0H + CaS04 2Li0H + Na2C03 - LiC03 + 2Na0H.
[0013] DETAILED DESCRIPTION: embodiment relates to the concentration of both quality and concentration, is to lepidolite as raw material extraction process will be explained in addition to lithium carbonate from lithium aluminum mica methods.
[0014] Example 1
(1) packing, the lithium mica crushed to 80-200 mesh, placed in a reaction apparatus, the main raw material of lithium mica chemical composition as follows (wt%)

(2) acid leaching fluorine: Take lithium mica, certain solid, liquid ratio, dilute sulfuric acid dropped into the kettle boiling, stirring constantly boiling process, an adequate response. While the reaction kettle containing hydrofluoric acid vapor is withdrawn after condensation into a liquid solution, recovered;
Process conditions of this embodiment is used in this step: lepidolite and 50% sulfuric acid solid, liquid mass ratio of 1: 3, the reaction temperature is 120 ° C, the reaction time for him,
(3) Separation: The solid-liquid mixture containing sulfate of Li + (¾ step fluorine after separation by filtration, the temperature at 100 ° C, and in the separation process, the separated solid residue with a temperature of 80 ° C hot water washing, detection and control of the filter ■ each constituent contents were Li2O 0. 61%; K2O 1. 07%, Na2O 0. 45%, Al2O3 8. 01%, SiO2 89. 74%, Fe2O3 'Rb2O 0. 123%, CsO 018%;. isolated residue recovered; the washing solution was separated by filtration and the mother liquor is 1, together with the mother liquor into the tank;
(4) The cryogenic separation: 1 diluted mother liquor is injected into the cooling tank, and adding Al2 (SO4) 3, so that the mother liquor 1 K +, Al3 + concentration is saturated, the formation of K +, A13 + saturated solution. Under constant stirring conditions, when the temperature dropped to 0~40 ° C, a mixed solution of rubidium, cesium, potassium alum precipitated; the mixture is separated by filtration, residues recovered filtrate liquor 2;
(5) and in addition to aluminum: The mother liquor was stirred for 2 cooling to 0~-30 ° C, isolated by filtration residue recovered filtrate was a solution to the filtrate was added calcium hydroxide emulsion under stirring to adjust the PH value of 7 ~ 8; 3 to form a mixed solution of liquor;
(6) separation: 3 the mother liquor by filtration, separation, control filtrate of Al3 + <0.008g / l, too filtrate liquor 4;
(7) concentration, filtration: The mother liquor was concentrated to 4 Li + concentration 20~45g / L, filtration;
(8) Shen Li: The mother liquor (7) Step 4 after filtration, sodium carbonate solution at 85 ° C temperature for 50 minutes, Shen Li;
(9) separating molded product: for (8) Step Shen lithium solution after the reaction was centrifuged to obtain crude lithium carbonate, rinsed with pure water after drying, to obtain lithium carbonate product. The filtered solution was recycled again after treatment, wash water is returned formulated lithium sodium carbonate solution.
[0015] Example 2 except as noted below, and process the rest of the same conditions as in Example 1 for the cryogenic separation of the mixed solution was added to a mixed solution of aluminum hydroxide control K +, A13 + concentration is saturated. (5) step and the addition of calcium oxide solution.
[0016] In addition to the above process through the production of lithium carbonate from high purity aluminum, the aluminum content of less product.