A method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore

Abstract

The present application provides a method for separating and recovering aluminum from an acid leach solution of aluminum-containing lithium ore, relating to the field of hydrometallurgy. The method comprises: removing iron from the acid leach solution of aluminum-containing lithium ore to obtain a deironed liquid; mixing the deironed liquid with an additive to obtain a mixed liquid, and then mixing the mixed liquid with a precipitant to obtain a mixed slurry; mixing the mixed slurry with aluminum hydroxide seed crystals, and then aging and solid-liquid separation to obtain a solid and a liquid; mixing the liquid with a causticizing agent and causticizing and evaporating it to obtain a mixed gas and a causticized evaporated slurry; and performing a second solid-liquid separation on the causticized evaporated slurry to obtain a solid and a liquid. The method provided in the present application comprehensively recovers aluminum from the lithium ore acid leach solution without introducing impurity ions, has a low lithium loss rate in the solution, can realize waste utilization of aluminum in the solution, reduces waste slag discharge, and the aluminum precipitant can be recycled and reused, with low precipitant consumption. The process is simple, the operation is stable, and it is suitable for industrial-scale production.

Description

Technical Field

[0001] The present application relates to the field of hydrometallurgy, and in particular to a method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore. Background Art

[0002] Currently, lithium extraction from lithium ore resources primarily utilizes the sulfuric acid and sulfate methods. The sulfuric acid method, in particular, boasts high adaptability and maturity, suitable for processing most lithium ore resources and achieving high lithium leaching rates. However, during the sulfuric acid method, significant amounts of impurities such as Fe and Al are leached into the solution during lithium ore processing, reaching concentrations of 0.1-20 g / L and 1-50 g / L, respectively.

[0003] Aluminum in the sulfuric acid leachate of lithium ore is usually not recycled and is removed as an impurity. The neutralization precipitation method is mainly used. By adding limestone and lime, the aluminum is precipitated and stored as aluminum hydroxide slag, and is not recycled. In addition, due to the strong adsorption of aluminum hydroxide slag in the conventional precipitation method, the Li loss rate during the precipitation process is 5-10%, which not only affects the lithium recovery rate, but also increases the amount of solid waste emissions, affecting the environment.

[0004] In view of this, the present application proposes to separate and recover aluminum from the lithium ore acid leaching solution to prepare aluminum hydroxide by-product, which can not only comprehensively utilize the aluminum in the solution, reduce the emission of lithium extraction process slag, but also improve the lithium recovery rate. Summary of the Invention

[0005] The purpose of this application is to provide a method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore to solve the above problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore, comprising:

[0008] removing iron from the acid leaching solution of the aluminum-lithium ore to obtain a deironed solution;

[0009] The iron-removed liquid is mixed with an additive to obtain a mixed liquid, and then the mixed liquid is mixed with a precipitant to obtain a mixed slurry; the additive comprises one or more of lauryl alcohol, ethylenediaminetetraacetic acid, citric acid, and polyethylene glycol;

[0010] The mixed slurry is mixed with aluminum hydroxide seed crystals, and then aged and subjected to a first solid-liquid separation to obtain a first solid and a first liquid; the first solid is used to prepare an aluminum hydroxide product;

[0011] The liquid is mixed with a causticizing agent and then causticized and evaporated to obtain a mixed gas and a causticized evaporated slurry; the mixed gas is used to prepare the precipitant;

[0012] The causticized evaporated slurry is subjected to a second solid-liquid separation to obtain a second solid and a second liquid; the second solid is calcium sulfate slag, and the second liquid is a lithium-containing solution.

[0013] Preferably, the acid leaching solution of the aluminum-lithium ore has a lithium content of 0.5-20 g / L, a total iron content of less than or equal to 0.1 g / L, an aluminum content of 5-50 g / L, and a pH value of 0.2-2.5.

[0014] Preferably, the amount of the additive is 1-2000 g / m 3 .

[0015] Preferably, the precipitant comprises aqueous ammonia and / or aqueous ammonium carbonate solution;

[0016] The method satisfies one or more of the following conditions:

[0017] (1) The concentrations of the aqueous ammonia and the aqueous ammonium carbonate solution are independently 50-500 g / L;

[0018] (2) The amount of the precipitant is 1-10 times the molar amount of aluminum in the mixed solution;

[0019] (3) The flow ratio of the mixed liquid to the precipitant is (1-20):1;

[0020] (4) The mixed liquid and the precipitant are mixed using a pipeline mixer and / or a venturi ejector.

[0021] Preferably, the method satisfies one or more of the following conditions:

[0022] (1) The amount of the seed crystal is 1-20 times the amount of aluminum hydroxide precipitation per unit time;

[0023] (2) The aging temperature is 0-100° C. and the aging time is 0.1-24 h;

[0024] (3) the aging is carried out under sealed conditions;

[0025] (4) The aging is carried out in 2-10 aging tanks connected in series, and the height difference between two adjacent aging tanks is 200-2000 mm;

[0026] (5) The end point pH of the aging is 3.5-8.

[0027] Preferably, the method satisfies one or more of the following conditions:

[0028] (1) The first solid-liquid separation is performed using one or more of a vacuum belt filter, a disc vacuum filter, a vertical filter press, a horizontal diaphragm filter press, and a thickener;

[0029] (2) After the first solid-liquid separation, the first solid matter is further washed and dried;

[0030] (3) The aluminum content of the first liquid is less than 0.1 g / L.

[0031] Preferably, the method satisfies one or more of the following conditions:

[0032] (1) The causticizing agent includes one or more of calcium oxide, calcium hydroxide, sodium hydroxide, and lithium hydroxide;

[0033] (2) The amount of the causticizing agent is 0.2-5 times the molar amount of ammonia in the first liquid;

[0034] (3) The temperature of the causticizing evaporation is 50-120°C and the time is 0.1-24h.

[0035] Preferably, the method satisfies one or more of the following conditions:

[0036] (1) The mixed gas is a mixed gas of ammonia and water vapor;

[0037] (2) The mixed gas is absorbed in an absorption tower to prepare an aluminum precipitant with an ammonia concentration of 20-250 g / L.

[0038] Preferably, the method satisfies one or more of the following conditions:

[0039] (1) The second solid-liquid separation is performed using one or more of a vacuum belt filter, a vacuum drum filter, a horizontal spiral centrifuge, and a horizontal diaphragm filter press;

[0040] (2) The calcium sulfate content in the calcium sulfate slag is 60-100%.

[0041] Preferably, the lithium carbonate product is prepared from the lithium-containing solution after impurities are removed.

[0042] Compared with the prior art, the advantages of this application include:

[0043] The method for separating and recovering aluminum from the acid leaching solution of aluminum-containing lithium ore provided by the present application has removed iron before aluminum precipitation, so that the aluminum hydroxide product obtained by aluminum precipitation has a high purity, and the aluminum can be used to prepare aluminum hydroxide products that meet the national standard GB / T4294-2010 for recovery. Compared with the traditional precipitation method for aluminum removal (iron and aluminum are precipitated together with the leaching residue), it not only avoids the discharge of waste aluminum slag during lithium extraction, but also realizes the waste utilization of aluminum in the solution. By using additives, aging and adding crystal seeds, the aluminum hydroxide prepared has a coarse particle size, a stable crystal morphology, and a lithium loss rate in the solution of less than 1%; compared with the lithium loss rate of 5 to 10% in the traditional precipitation method for aluminum removal, the loss of lithium in the aluminum separation process is reduced. The precipitant used is combined with caustic evaporation to achieve the renewable recycling of the precipitant, low material consumption and low cost.

[0044] The method provided in the present application for separating and recovering aluminum from the acid leaching solution of aluminum-containing lithium ore has simple operation and stable process, and is applicable to industrial-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0046] Figure 1 A schematic process flow diagram of a method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore is provided in an embodiment. DETAILED DESCRIPTION

[0047] In order to better illustrate the technical solution provided by this application, before the embodiments, an overall description of the technical solution is first given, as follows:

[0048] A method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore, comprising:

[0049] removing iron from the acid leaching solution of the aluminum-lithium ore to obtain a deironed solution;

[0050] The iron-removed liquid is mixed with an additive to obtain a mixed liquid, and then the mixed liquid is mixed with a precipitant to obtain a mixed slurry; the additive comprises one or more of lauryl alcohol, ethylenediaminetetraacetic acid, citric acid, and polyethylene glycol;

[0051] The mixed slurry is mixed with aluminum hydroxide seed crystals (a portion of which is taken from the first solid and used as seed crystals), and then aged and subjected to a first solid-liquid separation to obtain a first solid and a first liquid; the first solid is used to prepare an aluminum hydroxide product;

[0052] The liquid is mixed with a causticizing agent and then causticized and evaporated to obtain a mixed gas and a causticized evaporated slurry; the mixed gas is used to prepare the precipitant;

[0053] The causticized evaporated slurry is subjected to a second solid-liquid separation to obtain a second solid and a second liquid; the second solid is calcium sulfate slag, and the second liquid is a lithium-containing solution.

[0054] The role of additives is to reduce the surface tension of the solution, weaken its resistance to the aggregation of aluminum hydroxide particles, and thus accelerate the rate at which the seeds adsorb aluminum ions, which is beneficial to the growth of the seeds and thus increases the number of aluminum hydroxide particles; at the same time, some will change the growth direction of aluminum hydroxide and form a certain morphology.

[0055] In an optional embodiment, the acid leaching solution of the aluminum-lithium ore has a lithium content of 0.5-20 g / L, a total iron content of less than or equal to 0.1 g / L, an aluminum content of 5-50 g / L, and a pH value of 0.2-2.5.

[0056] Optionally, in the acid leaching solution of the aluminum-containing lithium ore, the lithium content may be 0.5 g / L, 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L or any value between 0.5 and 20 g / L, the total iron content may be 0.01 g / L, 0.05 g / L, 0.1 g / L or any value less than or equal to 0.1 g / L, the aluminum content may be 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L or any value between 5 and 50 g / L, and the pH value may be 0.2, 0.5, 1.0, 1.5, 2.0, 2.5 or any value between 0.2 and 2.5.

[0057] In an optional embodiment, the amount of the additive is 1-2000 g / m 3 .

[0058] Optionally, the amount of the additive can be 1g / m 3 , 10g / m 3 , 50g / m 3 , 100g / m 3 , 500g / m 3 , 1000g / m 3 , 1500g / m 3 , 2000g / m 3 or 1-2000g / m 3 Any value in between.

[0059] It should be noted that g / m 3 Refers to the amount of additives per cubic meter of iron removal liquid.

[0060] In an optional embodiment, the precipitant includes aqueous ammonia and / or aqueous ammonium carbonate solution;

[0061] Ammonia water and / or ammonium carbonate aqueous solution are used as precipitants, and other impurity ions that affect lithium extraction are not introduced while aluminum in the solution is precipitated and separated.

[0062] The method satisfies one or more of the following conditions:

[0063] (1) The concentrations of the aqueous ammonia and the aqueous ammonium carbonate solution are independently 50-500 g / L;

[0064] Optionally, the concentrations of the aqueous ammonia and the aqueous ammonium carbonate solution may be independently 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L, 400 g / L, 450 g / L, 500 g / L or any value between 50 and 500 g / L;

[0065] (2) The amount of the precipitant is 1-10 times the molar amount of aluminum in the mixed solution;

[0066] Optionally, the amount of the precipitant can be 1 times, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, or any value between 1 and 10 times the molar amount of aluminum in the mixed solution;

[0067] (3) The flow ratio of the mixed liquid to the precipitant is (1-20):1;

[0068] Optionally, the flow ratio of the mixed liquid to the precipitant can be 1:1, 5:1, 10:1, 15:1, 20:1 or any value between (1-20):1;

[0069] (4) The mixed liquid and the precipitant are mixed using a pipeline mixer and / or a venturi ejector.

[0070] The use of the above-mentioned equipment for rapid mixing is also one of the factors affecting the preparation of aluminum hydroxide with stable crystalline morphology and coarse particle size (D50 is 20 to 75 microns); among them, rapid mixing is mainly used to form a stable morphology, while adding crystal seeds and aging are mainly used to increase the particle size.

[0071] In an optional embodiment, the method satisfies one or more of the following conditions:

[0072] (1) The amount of the seed crystal is 1-20 times the amount of aluminum hydroxide precipitation per unit time;

[0073] Optionally, the amount of the seed crystals can be 1 times, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 11 times, 12 times, 13 times, 14 times, 15 times, 16 times, 17 times, 18 times, 19 times, 20 times the amount of aluminum hydroxide precipitation per unit time, or any value between 1 and 20 times;

[0074] (2) The aging temperature is 0-100° C. and the aging time is 0.1-24 h;

[0075] Optionally, the aging temperature may be 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or any value between 0-100°C, and the aging time may be 0.1h, 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or any value between 0.1-24h;

[0076] (3) the aging is carried out under sealed conditions;

[0077] (4) The aging is carried out in 2-10 aging tanks connected in series, and the height difference between two adjacent aging tanks is 200-2000 mm;

[0078] The number of aging tanks can be any number of 2, 3, 4, 5, 6, 7, 8, 9, or 10; the height difference between two adjacent aging tanks can be 200 mm, 500 mm, 1000 mm, 1500 mm, 2000 mm, or any value between 200 and 2000 mm;

[0079] There is a height difference between the tanks, and the slurry flows by gravity between the aging tanks using the difference in liquid levels. Each aging tank uses the method of discharging slurry from the bottom and adding slurry from the top, and the slurry flows by gravity from the first tank to the last tank.

[0080] (5) The end point pH of the aging is 3.5-8.

[0081] Optionally, the endpoint pH of the aging can be 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8 or any value between 3.5 and 8.

[0082] In an optional embodiment, the method satisfies one or more of the following conditions:

[0083] (1) The first solid-liquid separation is performed using one or more of a vacuum belt filter, a disc vacuum filter, a vertical filter press, a horizontal diaphragm filter press, and a thickener;

[0084] (2) After the first solid-liquid separation, the first solid matter is further washed and dried;

[0085] (3) The aluminum content of the first liquid is less than 0.1 g / L.

[0086] In an optional embodiment, the method satisfies one or more of the following conditions:

[0087] (1) The causticizing agent includes one or more of calcium oxide, calcium hydroxide, sodium hydroxide, and lithium hydroxide;

[0088] (2) The amount of the causticizing agent is 0.2-5 times the molar amount of ammonia in the first liquid;

[0089] Optionally, the amount of the causticizing agent may be 0.2 times, 0.5 times, 1 times, 2 times, 3 times, 4 times, 5 times, or any value between 0.2 and 5 times the molar amount of ammonia in the first liquid;

[0090] (3) The temperature of the causticizing evaporation is 50-120°C and the time is 0.1-24h.

[0091] Optionally, the temperature of the causticizing evaporation can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or any value between 50-120°C, and the time can be 0.1h, 1h, 6h, 12h, 18h, 24h or any value between 0.1-24h.

[0092] In an optional embodiment, the method satisfies one or more of the following conditions:

[0093] (1) The mixed gas is a mixed gas of ammonia and water vapor;

[0094] (2) The mixed gas is absorbed in an absorption tower to prepare an aluminum precipitant with an ammonia concentration of 20-250 g / L.

[0095] Optionally, the ammonia concentration of the aluminum precipitant prepared by absorbing the mixed gas in an absorption tower can be 20g / L, 50g / L, 100g / L, 150g / L, 200g / L, 250g / L or any value between 20-250g / L.

[0096] In an optional embodiment, the method satisfies one or more of the following conditions:

[0097] (1) The second solid-liquid separation is performed using one or more of a vacuum belt filter, a vacuum drum filter, a horizontal spiral centrifuge, and a horizontal diaphragm filter press;

[0098] (2) The calcium sulfate content in the calcium sulfate slag is 60-100%.

[0099] Optionally, the calcium sulfate content in the calcium sulfate slag may be 60%, 70%, 80%, 90%, 100% or any value between 60-100%.

[0100] In an optional embodiment, the lithium carbonate product is prepared after removing impurities from the lithium-containing solution.

[0101] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0102] Example 1

[0103] like Figure 1 As shown, the present application provides a method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore, and the specific steps are as follows:

[0104] The solution after acid leaching and iron removal from a clay-type lithium ore contains 2.5g / L lithium, 0.01g / L iron, 25g / L aluminum, and a pH of 2.0. 100g of polyethylene glycol is added per cubic meter of solution and dissolved and mixed uniformly to prepare an aluminum precipitation solution. This solution is pumped into inlet A of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, ammonia (precipitant) prepared to a concentration of 150g / L and supplemented with a molar amount 3.1 times the molar amount of aluminum in the solution is pumped into inlet B of the rapid mixer at a flow rate of Q2 to rapidly mix the aluminum precipitation solution and the precipitant. The rapid mixer consists of two pipeline mixers connected in series, and the flow ratio of Q1 to Q2 during aluminum precipitation is 3.1:1. The slurry mixed by the rapid mixer flows by gravity into a closed stirring aging tank with stirring. The amount of seed crystals returned is 6 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 45°C, the aging time is 6 hours, and the aging tanks are connected in series with 3 tanks. The height difference between the tanks is 600mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and feeding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 5.5. The slurry discharged from aging is filtered and washed by a vertical filter press to separate the filter cake and filtrate in the slurry; the filter cake is dried by a dryer to prepare a product that meets the national standard GB / T The AH-2 aluminum hydroxide product, 4294-2010, has an aluminum hydroxide particle size (D50) of 45 microns. The aluminum precipitation rate in the solution is 99.8%, and the aluminum content in the filtrate is 0.06 g / L. The filtrate is causticized and evaporated with a calcium oxide causticizing agent added in an amount equal to 0.6 times the molar amount of ammonia in the filtrate. The causticization temperature and evaporation time are 95°C and 1 hour. The gas generated by the causticization evaporation is a mixture of ammonia and water vapor, which is absorbed in a spray absorption tower to produce an aluminum precipitant with an ammonia concentration of 150 g / L, which is then returned for aluminum precipitation. The slurry formed by the causticization evaporation is filtered and washed using a vacuum belt filter, resulting in a calcium sulfate residue with a calcium sulfate content (dry basis) of 77%. After treatment, it can be used as a cement construction raw material. The lithium loss rate of the solution during the aluminum precipitation process is 0.35%. The filtrate is a lithium-containing solution, which is prepared by conventional methods after impurity removal to meet the requirements of the national standard (GB / T 11075-2013) for Li2CO3-0 lithium carbonate product.

[0105] Example 2

[0106] The present application provides a method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore, the specific steps of which are as follows:

[0107] After calcination, acidification, roasting, leaching, and iron removal, a spodumene concentrate solution was prepared, containing 21 g / L lithium, 0.006 g / L iron, and 14 g / L aluminum, with a pH of 1.5. 50 g of ethylenediaminetetraacetic acid (EDTA) was added per cubic meter of solution and dissolved and mixed uniformly to prepare an aluminum precipitation solution. This solution was pumped into inlet A of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, ammonia precipitant (prepared to a concentration of 120 g / L and with a molar amount equal to 3.1 times the molar amount of aluminum in the solution) was pumped into inlet B of the rapid mixer at a flow rate of Q2, rapidly mixing the aluminum precipitation solution and precipitant. The rapid mixer consisted of two parallel Venturi ejector mixers. During aluminum precipitation, the flow ratio of Q1 to Q2 was 4.4:1. The slurry mixed by the rapid mixer flows by gravity into a closed stirring aging tank with stirring. The amount of returned seed crystals is 3 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 40°C, the aging time is 4 hours, and the aging tanks are connected in series with two tanks. The height difference between the tanks is 800mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and feeding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 5.0. The slurry discharged from the aging was filtered and washed using a horizontal diaphragm filter press to separate the filter cake and filtrate in the slurry; the filter cake was dried using a dryer to prepare AH-2 aluminum hydroxide product that meets the national standard GB / T4294-2010, with an aluminum hydroxide particle size D50 of 34 microns; the aluminum precipitation rate in the solution was 99.6%, and the aluminum content in the filtrate was 0.05 g / L; calcium oxide causticizing agent was added to the filtrate for caustic evaporation, the amount of causticizing agent added was 0.7 times the molar amount of ammonium in the filtrate, the caustic evaporation temperature was 90°C, and the caustic evaporation temperature was 90°C. The evaporation time is 2 hours; the gas formed by causticizing evaporation is a mixture of ammonia and water vapor, which is absorbed by a spray absorption tower to produce an aluminum precipitant with an ammonia concentration of 120 g / L, and is returned for aluminum precipitation; the slurry formed by causticizing evaporation is filtered / washed by a vacuum belt filter, and the filter residue is a calcium sulfate residue with a calcium sulfate content (dry basis) of 76%, which can be used as a cement construction raw material after treatment; the lithium loss rate of the solution during the aluminum precipitation process is 0.2%; the filtrate is a lithium-containing solution, which is prepared by conventional methods after impurities are removed to prepare a lithium carbonate product that meets the national standard (GB / T 11075-2013) Li2CO3-0.

[0108] Example 3

[0109] The present application provides a method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore, the specific steps of which are as follows:

[0110] The solution after calcination, acid leaching, and iron removal of a mixed lithium ore contains 10g / L lithium, 0.004g / L iron, and 10g / L aluminum, with a pH of 1.2. 200g of citric acid is added per cubic meter of solution and dissolved and mixed uniformly to prepare a solution for aluminum precipitation. This solution is pumped into inlet A of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, ammonium carbonate, prepared to a concentration of 300g / L and with a molar amount 1.6 times the molar amount of aluminum in the solution, is pumped into inlet B of the rapid mixer at a flow rate of Q2, rapidly mixing the solution and precipitant. The rapid mixer consists of three pipeline mixers connected in series, and the flow ratio of Q1 to Q2 during aluminum precipitation is 5.3:1. The slurry mixed by the rapid mixer flows by gravity into a closed stirring aging tank with stirring. The amount of seed crystals returned is 4 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 60°C, the aging time is 8 hours, and the aging tanks are connected in series with 4 tanks. The height difference between the tanks is 400mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and feeding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 6.0. The slurry discharged from aging is filtered and washed by a horizontal diaphragm filter press to separate the filter cake and filtrate in the slurry; the filter cake is dried by a dryer to prepare a product that meets the national standard GB / T The AH-2 aluminum hydroxide product of 4294-2010 has an aluminum hydroxide particle size D50 of 40 microns; the aluminum precipitation rate in the solution is 99.6%, and the aluminum content in the filtrate is 0.04g / L; the filtrate is added with a calcium oxide causticizer for causticization and evaporation, the amount of causticizer added is 0.75 times the molar amount of ammonium in the filtrate, the causticization evaporation temperature is 85°C, and the causticization evaporation time is 3 hours; the gas formed by causticization evaporation is a mixture of ammonia and water vapor, which is absorbed in a packed absorption tower and then introduced into a carbon dioxide gas production process. An aluminum precipitant with an ammonium carbonate concentration of 300 g / L is obtained and returned for aluminum precipitation; the slurry formed by causticizing and evaporation is filtered / washed using a vacuum belt filter, and the filter residue is a calcium sulfate residue with a calcium sulfate content (dry basis) of 78%, which can be used as a cement construction raw material after treatment; the lithium loss rate of the solution during the aluminum precipitation process is 0.18%; the filtrate is a lithium-containing solution, which is removed by conventional methods to prepare a lithium carbonate product that meets the national standard (GB / T11075-2013) Li2CO3-0.

[0111] Comparative Example 1

[0112] The solution after acid leaching and iron removal from a clay-type lithium ore contains 2.5g / L lithium, 0.01g / L iron, 25g / L aluminum, and a pH of 2.0. 100g of polyethylene glycol is added per cubic meter of solution and dissolved and mixed uniformly to prepare an aluminum precipitation solution. This solution is pumped into inlet A of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, sodium hydroxide (precipitant) prepared to a concentration of 200g / L and with a molar amount 3.1 times the molar amount of aluminum in the solution added is pumped into inlet B of the rapid mixer at a flow rate of Q2, rapidly mixing the aluminum precipitation solution and the precipitant. The rapid mixer consists of two pipeline mixers connected in series, and the flow ratio of Q1 to Q2 during aluminum precipitation is 3.1:1. The slurry mixed by the rapid mixer flows by gravity into a closed stirring aging tank with stirring. The amount of returned seed crystals is 6 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 45°C, the aging time is 6 hours, and the aging tanks are connected in series with three tanks. The height difference between the tanks is 600mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and feeding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 5.5. The slurry discharged from the aging process was filtered and washed using a vertical filter press to separate the filter cake and filtrate from the slurry. The filter cake was dried in a dryer to produce an AH-2 aluminum hydroxide product that complies with the national standard GB / T 4294-2010, with an aluminum hydroxide particle size D50 of 10 microns. The aluminum precipitation rate in the solution was 99.8%, and the aluminum content in the filtrate was 0.05 g / L. The lithium loss rate of the solution during the precipitation process was 8.9%. Although sodium hydroxide precipitation can also achieve precipitation and recovery of aluminum from the solution, sodium hydroxide is a strong base and easily forms aluminum hydroxide colloids during the precipitation process, which adsorbs lithium from the solution and increases the lithium loss rate. In addition, sodium hydroxide precipitation introduces a large amount of sodium ions into the solution, resulting in a sodium sulfate content of 190 g / L in the solution after precipitation. During the solution concentration process, sodium sulfate easily crystallizes and precipitates, which is not conducive to the subsequent recovery of lithium in the filtrate. Moreover, the sodium hydroxide precipitant is difficult to regenerate and recycle during the precipitation process, resulting in high consumption and high precipitation costs, which are not conducive to industrial application.

[0113] Comparative Example 2

[0114] The solution after acid leaching and iron removal from a clay-type lithium ore contains 2.5g / L lithium, 0.01g / L iron, 25g / L aluminum, and a pH of 2.0. Without additives, the solution is directly pumped into the A inlet of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, ammonia (precipitant) prepared to a concentration of 150g / L and supplemented with a molar amount 3.1 times the molar amount of aluminum in the solution is pumped into the B inlet of the rapid mixer at a flow rate of Q2 using a metering device, rapidly mixing the solution to be precipitated with the precipitant. The rapid mixer consists of two pipeline mixers connected in series, and the flow ratio of Q1 to Q2 during aluminum precipitation is 3.1:1. The slurry mixed by the rapid mixer flows by gravity into a closed stirring aging tank with stirring. The amount of returned seed crystals is 6 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 45°C, the aging time is 6 hours, and the aging tanks are connected in series with three tanks. The height difference between the tanks is 600mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and feeding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 5.5. The slurry discharged from aging is filtered and washed using a vertical filter press to separate the filter cake and filtrate in the slurry; the filter cake is dried using a dryer to prepare an AH-2 aluminum hydroxide product that meets the national standard GB / T 4294-2010, and the aluminum hydroxide particle size D50 is 18 microns; the aluminum precipitation rate in the solution is 99.7%, and the aluminum content in the filtrate is 0.07 g / L; the aluminum hydroxide particle size obtained by precipitation without adding additives is relatively small, and the lithium loss rate of the solution during precipitation is 1.2% (caused by aluminum hydroxide adsorption), which is higher than the lithium loss rate (0.35%) when precipitation with additives is added.

[0115] Comparative Example 3

[0116] The solution after acid leaching and iron removal from a clay-type lithium ore contains 2.5g / L lithium, 0.01g / L iron, 25g / L aluminum, and a pH of 2.0. 100g of polyethylene glycol is added per cubic meter of solution and dissolved and mixed to prepare an aluminum precipitation solution. This solution is pumped into an aluminum precipitation stirring tank at a flow rate of Q1 using a metering device. Simultaneously, ammonia (precipitant) prepared at a concentration of 150g / L and with a molar amount 3.1 times the molar amount of aluminum in the solution is pumped into the aluminum precipitation stirring tank using a metering device at a flow rate of Q2. The flow ratio of Q1 to Q2 is 3.1:1. The aluminum precipitation slurry flows by gravity into a closed stirring aging tank with stirring. The amount of returned seed crystals is 6 times the amount of aluminum hydroxide precipitation per unit time, the aging temperature is 45°C, the aging time is 6 hours, and the aging tanks are connected in series with three tanks. The height difference between the tanks is 600mm. The slurry flows by gravity between the aging tanks using the liquid level difference of the slurry. Each aging tank adopts the method of discharging slurry from the bottom and adding slurry from the top. The slurry flows by gravity from the first tank to the last tank, and the pH value of the slurry at the end of aging is controlled to be 5.5. The slurry discharged from aging is filtered and washed using a vertical filter press to separate the filter cake and filtrate in the slurry; the filter cake is dried using a dryer to prepare an AH-2 aluminum hydroxide product that meets the national standard GB / T 4294-2010, with an aluminum hydroxide particle size D50 of 42 microns; the aluminum precipitation rate in the solution is 99.8%, and the aluminum content in the filtrate is 0.06 g / L; however, the lithium loss rate of the solution during the aluminum precipitation process is 2.3%; because the aluminum precipitation liquid and the precipitant are directly added to the aluminum precipitation stirring tank, the mixing intensity is limited, and rapid diffusion, mixing and reaction of the solution and the precipitant cannot be achieved, resulting in the formation of a small amount of amorphous aluminum hydroxide, which increases the lithium adsorption loss in the solution.

[0117] Comparative Example 4

[0118] The solution after acid leaching and iron removal from a clay-type lithium ore contains 2.5g / L lithium, 0.01g / L iron, 25g / L aluminum, and a pH of 2.0. 100g of polyethylene glycol is added per cubic meter of solution and dissolved and mixed uniformly to prepare an aluminum precipitation solution. This solution is pumped into inlet A of a rapid mixer at a flow rate of Q1 using a metering device. Simultaneously, ammonia (precipitant) prepared to a concentration of 150g / L and supplemented with a molar amount 3.1 times the molar amount of aluminum in the solution is pumped into inlet B of the rapid mixer at a flow rate of Q2 to rapidly mix the aluminum precipitation solution and the precipitant. The rapid mixer consists of two pipeline mixers connected in series, and the flow ratio of Q1 to Q2 during aluminum precipitation is 3.1:1. The slurry mixed in the rapid mixer was allowed to flow by gravity into a closed stirring tank with stirring, and the precipitation pH value was controlled to be 5.5. After stirring for 1 hour, the slurry was discharged and filtered and washed using a vertical filter press to separate the filter cake and filtrate in the slurry. The filter cake was dried using a dryer to prepare aluminum hydroxide with a particle size D50 of 15 microns. The particle size was fine, and the filtration performance of the aluminum hydroxide was significantly reduced. The aluminum precipitation rate in the solution was 99.5%, and the aluminum content in the filtrate was 0.12 g / L, which was lower than that in Example 1. In addition, the lithium loss rate of the solution during the aluminum precipitation process was 5.7%, which was higher than that in Example 1.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for separating and recovering aluminum from an acid leaching solution of an aluminum-containing lithium ore, characterized in that: include: Deironing the aluminum-lithium ore acid leaching solution to obtain a deironed solution; The iron-removed liquid is mixed with an additive to obtain a mixed liquid, and then the mixed liquid is mixed with a precipitant to obtain a mixed slurry; the additive comprises one or more of lauryl alcohol, ethylenediaminetetraacetic acid, citric acid, and polyethylene glycol; The mixed slurry is mixed with aluminum hydroxide seed crystals, and then aged and subjected to a first solid-liquid separation to obtain a first solid and a first liquid; the first solid is used to prepare an aluminum hydroxide product; The first liquid is mixed with a causticizing agent and then causticized and evaporated to obtain a mixed gas and a causticized evaporated slurry; the mixed gas is used to prepare the precipitant; The causticized evaporated slurry is subjected to a second solid-liquid separation to obtain a second solid and a second liquid; the second solid is calcium sulfate slag, and the second liquid is a lithium-containing solution; The acid leaching solution of the aluminum-containing lithium ore has a lithium content of 0.5-20 g / L, a total iron content of less than or equal to 0.1 g / L, an aluminum content of 5-50 g / L, and a pH value of 0.2-2.5; The dosage of the additive is 1-2000g / m 3 ; The precipitant includes aqueous ammonia and / or aqueous ammonium carbonate solution; the concentrations of the aqueous ammonia and the aqueous ammonium carbonate solution are independently 50-500 g / L; The amount of the precipitant is 1-10 times the molar amount of aluminum in the mixed solution; The flow ratio of the mixed liquid to the precipitant is (1-20):1; The mixed liquid and the precipitant are mixed using a pipeline mixer and / or a venturi ejector; the amount of the seed crystal is 1-20 times the amount of aluminum hydroxide precipitation per unit time; The aging temperature is 0-100° C. and the aging time is 0.1-24 h; The aging is carried out under sealed conditions; The aging is carried out in 2-10 aging tanks connected in series, and the height difference between two adjacent aging tanks is 200-2000mm; The endpoint pH of the aging is 3.5-8; The causticizing agent includes one or more of calcium oxide, calcium hydroxide, sodium hydroxide, and lithium hydroxide; the amount of the causticizing agent is 0.2-5 times the molar amount of ammonia in the first liquid; the temperature of the causticizing evaporation is 50-120° C., and the time is 0.1-24 hours.

2. The method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore according to claim 1, characterized in that: One or more of the following conditions are met: (1) The first solid-liquid separation is performed using one or more of a vacuum belt filter, a disc vacuum filter, a vertical filter press, a horizontal diaphragm filter press, and a thickener; (2) After the first solid-liquid separation, the first solid matter is further washed and dried; (3) The aluminum content of the first liquid is less than 0.1 g / L.

3. The method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore according to claim 1, characterized in that: The method satisfies one or more of the following conditions: (1) The mixed gas is a mixed gas of ammonia and water vapor; (2) The mixed gas is absorbed in an absorption tower to prepare an aluminum precipitant with an ammonia concentration of 20-250 g / L.

4. The method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore according to claim 1, characterized in that: The method satisfies one or more of the following conditions: (1) The second solid-liquid separation is performed using one or more of a vacuum belt filter, a vacuum drum filter, a horizontal spiral centrifuge, and a horizontal diaphragm filter press; (2) The calcium sulfate content in the calcium sulfate slag is 60-100%.

5. The method for separating and recovering aluminum from an acid leaching solution of aluminum-containing lithium ore according to claim 1, characterized in that: The lithium carbonate product is prepared by removing impurities from the lithium-containing solution.

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