A comprehensive recycling method for sedimentary lithium resources

Abstract

The present invention provides a comprehensive recycling method for sedimentary lithium resources, belonging to the technical field of comprehensive recycling of lithium resources. The method comprises the following steps: crushing sedimentary lithium ore, grinding, sieving, and obtaining ground minerals; reverse flotation of the ground minerals to obtain flotation concentrates and flotation tailings; sulfuric acid slaking and water leaching of the flotation concentrates are sequentially performed to obtain lithium-containing leachate; the lithium-containing leachate is purified and impurities are removed to obtain a purified liquid; sodium carbonate is added to the purified liquid for reaction, and precipitation is collected to obtain lithium carbonate; the inhibitor used in the flotation is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1: (1-3): (0.5-2), and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1: (1-2.5): (0.5-1.5). The method of the present invention does not require high-temperature roasting, and the post-treatment of the lithium-containing leachate is simple, and the lithium grade in the obtained lithium concentrate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive recovery of lithium resources, and in particular to a comprehensive recovery and utilization method of sedimentary lithium resources. Background Art

[0002] Lithium is the lightest metal in nature and is widely used in traditional fields such as glass, ceramics, metallurgy, medicine, and organic synthesis. At present, there are three main types of lithium deposits found in nature: salt lake brine type, granite pegmatite-alkali feldspar granite type, and sedimentary type. Compared with the world's major lithium resource countries, China does not have an advantage in the resources of the first two types of deposits, while sedimentary lithium mines are a potential lithium resource library. The lithium content in China's bauxite (rock) ranks among the top among various sedimentary lithium mines, but there is currently no sedimentary lithium mine that has been independently developed and utilized.

[0003] Document CN110042262A discloses a method for selectively leaching low-grade sedimentary lithium ore, which roasts at 500-700°C to obtain cooked ore, and then uses inorganic acid to leach the cooked ore at 20-60°C to obtain a lithium-rich solution. The roasting reaction temperature of this method is relatively high, and the energy consumption is high. At the same time, in this method, part of the silicon element is leached into the solution, making subsequent impurity removal more difficult. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a comprehensive recovery and utilization method of sedimentary lithium resources. The method provided by the present invention does not require high-temperature roasting, has low energy consumption, and is convenient and controllable to operate.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A comprehensive recycling method for sedimentary lithium resources comprises the following steps:

[0007] Step 1. crushing, grinding and sieving the sedimentary lithium ore to obtain finely ground minerals;

[0008] Step 2. reverse flotation the ground mineral to obtain flotation concentrate and flotation tailings;

[0009] Step 3. The flotation concentrate is subjected to sulfuric acid aging and water leaching in sequence to obtain a lithium-containing leaching solution;

[0010] Step 4. purifying and removing impurities from the lithium-containing leaching solution to obtain a purified solution;

[0011] Step 5. adding sodium carbonate to the purified liquid to react, collecting the precipitate, and obtaining lithium carbonate;

[0012] The depressant used in the flotation is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1: (1-3): (0.5-2), and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1: (1-2.5): (0.5-1.5).

[0013] In some embodiments of the present invention, the Li 2 The grade of O is 0.1% to 0.6%.

[0014] In some embodiments of the present invention, the dosage of the inhibitor is 80-160 g / t, and the dosage of the collector is 100-180 g / t.

[0015] In some embodiments of the present invention, during reverse flotation, the pH value of the reverse flotation system is 7.5-8.

[0016] In some embodiments of the present invention, the solution used to adjust the pH value of the reverse flotation system to 7.5-8 is a sodium hydroxide solution.

[0017] In some embodiments of the present invention, the mass concentration of sulfuric acid used in the sulfuric acid aging is 70-80%; the temperature of the sulfuric acid aging is 130-160° C., and the time is 50-80 min.

[0018] In some embodiments of the present invention, the purification and impurity removal of the leachate is specifically as follows: first, a hydrogen peroxide solution is added to the lithium-containing leachate to oxidize the ferrous ions into ferric ions, and then a sodium hydroxide solution is added to adjust the pH of the reaction system to 12, so that the iron forms an iron hydroxide precipitate; after filtering the precipitate, the pH of the reaction solution 1 is adjusted to 7 to form an aluminum hydroxide precipitate; after filtering the precipitate, the pH of the reaction solution 2 is adjusted to 6-7, sodium oxalate is added to the reaction solution to form a calcium oxalate precipitate, and after filtering the precipitate, the reaction solution 3 is concentrated to obtain a concentrated salt and a concentrated solution, the concentrated solution is cooled to 10-20°C, and the solid-liquid separation is performed to obtain a cooling salt and a purified solution.

[0019] In some embodiments of the present invention, after collecting the precipitate, the process further comprises the steps of washing and drying the precipitate.

[0020] The present invention discloses the following technical effects:

[0021] The present invention adopts the process flow of reverse flotation, selectively inhibits spodumene through the coordination between inhibitor starch, dextrin and tartaric acid, prevents it from floating, and simultaneously utilizes the coordination between collectors coconut amine, sodium dodecyl sulfate and sodium oleate to collect gangue minerals, the formed foam layer is scraped out to form tailings, and spodumene is left in the tank, and the lithium concentrate obtained contains Li 2 O is of high quality.

[0022] The method provided by the invention does not require high-temperature roasting, and no impurities such as silicon are introduced into the lithium-containing leaching solution, and the post-treatment of the leaching solution is simple. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] The present invention provides a comprehensive recycling method for sedimentary lithium resources, comprising the following steps:

[0029] Step 1. Sedimentary lithium ore (Li 2 O grade is 0.1% to 0.6%), crushed, ground, and passed through a 200-mesh sieve to obtain finely ground minerals;

[0030] Step 2. Mixing the ground mineral with water to obtain a slurry;

[0031] Step 3. adding sodium hydroxide to the slurry to adjust the pH value of the slurry to 7.5-8, then adding 80-160 g / t of inhibitor and 100-180 g / t of collector, flotation is performed by a flotation machine, the gangue minerals captured by the collector form a foam layer, which is scraped out to become flotation tailings, and the flotation concentrate (spodumene) remains in the tank; wherein the inhibitor is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1:(1-3):(0.5-2), and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1:(1-2.5):(0.5-1.5);

[0032] Step 4: Sulfuric acid and flotation concentrate are mixed at a liquid-solid ratio of 1-2:1, reacted at 130-160° C. for 50-80 min, and then immersed in water to obtain a lithium-containing leaching solution;

[0033] Step 5. First, add hydrogen peroxide solution to the lithium-containing leachate to oxidize ferrous ions into ferric ions, then add sodium hydroxide solution to adjust the pH of the reaction system to 12, so that the iron forms ferric hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 1 to 7 to form aluminum hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 2 to 6-7, add sodium oxalate to the reaction solution to form calcium oxalate precipitation, filter the precipitation, and concentrate the reaction solution 3 to obtain concentrated salt and concentrated solution, cool the concentrated solution to 10-20° C., and perform solid-liquid separation to obtain cooling salt and purified solution;

[0034] Step 5. Add sodium carbonate to the purified liquid for reaction, collect the precipitate, and obtain lithium carbonate.

[0035] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0036] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0037] The sedimentary lithium ore used in the embodiment is a sedimentary lithium ore in Guizhou.

[0038] Example 1

[0039] Step 1. Sedimentary lithium ore (Li 2 O grade is 0.45%), crushed, ground, and passed through a 200-mesh sieve to obtain finely ground minerals.

[0040] Step 2: Mix the ground mineral with water to prepare a slurry with a mass concentration of 35%.

[0041] Step 3. Sodium hydroxide is added to the pulp to adjust the pH value of the pulp to 7.5, and then 100 g / t of inhibitor and 150 g / t of collector are added, and flotation is performed by a flotation machine. The gangue minerals captured by the collector form a foam layer, which is scraped out to become flotation tailings, while the flotation concentrate (spodumene) remains in the tank; wherein the inhibitor is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1:1:0.5, and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1:1:1.5; Li in the flotation concentrate is obtained by reverse flotation. 2 The grade of O is 1.88%.

[0042] Step 4. Sulfuric acid (mass concentration of 70%) and 1000 g of flotation concentrate are mixed at a liquid-to-solid ratio of 2:1, and reacted at 150°C for 80 min; then 3.0 L of water is added for stirring and leaching, the leaching temperature is 25°C, and the solid-liquid separation is performed after the leaching time is 10 min to obtain a lithium-containing leachate.

[0043] Step 5. First, add hydrogen peroxide solution to the lithium-containing leachate to oxidize ferrous ions into ferric ions, then add sodium hydroxide solution to adjust the pH of the reaction system to 12, so that the iron forms iron hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 1 to 7 to form aluminum hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 2 to 6, add sodium oxalate to the reaction solution to form calcium oxalate precipitation, filter the precipitation, concentrate the reaction solution 3 by 3 / 4 to obtain concentrated salt and concentrated solution, cool the concentrated solution to 10°C, and separate the solid and liquid to obtain cooling salt and purified solution.

[0044] Step 5. Add a sodium carbonate solution with a concentration of 300 g / L to the purified liquid and react for 30 minutes. Collect the precipitate, wash it with water, and dry it to obtain a lithium carbonate product.

[0045] Example 2

[0046] Step 1. Sedimentary lithium ore (Li 2 O grade is 0.45%), crushed, ground, and passed through a 200-mesh sieve to obtain finely ground minerals.

[0047] Step 2: Mix the ground mineral with water to prepare a slurry with a mass concentration of 35%.

[0048] Step 3. Sodium hydroxide is added to the pulp to adjust the pH value of the pulp to 7.5, and then 150g / t of inhibitor and 180g / t of collector are added, and flotation is performed by a flotation machine. The gangue minerals captured by the collector form a foam layer, which is scraped out to become flotation tailings, while the flotation concentrate (spodumene) remains in the tank; wherein the inhibitor is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1:2:1, and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1:1.5:1.5; Li in the flotation concentrate is obtained by reverse flotation. 2 The grade of O is 2.02%.

[0049] Step 4. Sulfuric acid (mass concentration of 70%) and 1000 g of flotation concentrate are mixed at a liquid-to-solid ratio of 2:1, and reacted at 150°C for 80 min; then 3.0 L of water is added for stirring and leaching, the leaching temperature is 25°C, and the solid-liquid separation is performed after the leaching time is 10 min to obtain a lithium-containing leachate.

[0050] Step 5. First, add hydrogen peroxide solution to the lithium-containing leachate to oxidize ferrous ions into ferric ions, then add sodium hydroxide solution to adjust the pH of the reaction system to 12, so that the iron forms iron hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 1 to 7 to form aluminum hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 2 to 6, add sodium oxalate to the reaction solution to form calcium oxalate precipitation, filter the precipitation, concentrate the reaction solution 3 by 3 / 4 to obtain concentrated salt and concentrated solution, cool the concentrated solution to 10°C, and separate the solid and liquid to obtain cooling salt and purified solution.

[0051] Step 5. Add a sodium carbonate solution with a concentration of 300 g / L to the purified liquid and react for 30 minutes. Collect the precipitate, wash it with water, and dry it to obtain a lithium carbonate product.

[0052] Comparative Example 1

[0053] Step 1. Sedimentary lithium ore (Li 2 O grade is 0.45%), crushed, ground, and passed through a 200-mesh sieve to obtain finely ground minerals.

[0054] Step 2: Mix the ground mineral with water to prepare a slurry with a mass concentration of 35%.

[0055] Step 3. Sodium hydroxide is added to the pulp to adjust the pH value of the pulp to 7.5, and then 150g / t of inhibitor and 180g / t of collector are added. The flotation is carried out by a flotation machine. The gangue minerals captured by the collector form a foam layer, which is scraped out to become flotation tailings, while the flotation concentrate (spodumene) remains in the tank; wherein the inhibitor is starch and the collector is sodium dodecyl sulfate; Li in the flotation concentrate is obtained by reverse flotation. 2 The grade of O is 1.27%.

[0056] Step 4. Sulfuric acid (mass concentration of 70%) and 1000 g of flotation concentrate are mixed at a liquid-to-solid ratio of 2:1, and reacted at 150°C for 80 min; then 3.0 L of water is added for stirring and leaching, the leaching temperature is 25°C, and the solid-liquid separation is performed after the leaching time is 10 min to obtain a lithium-containing leachate.

[0057] Step 5. First, add hydrogen peroxide solution to the lithium-containing leachate to oxidize ferrous ions into ferric ions, then add sodium hydroxide solution to adjust the pH of the reaction system to 12, so that the iron forms iron hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 1 to 7 to form aluminum hydroxide precipitation; after filtering the precipitation, adjust the pH of the reaction solution 2 to 6, add sodium oxalate to the reaction solution to form calcium oxalate precipitation, filter the precipitation, concentrate the reaction solution 3 by 3 / 4 to obtain concentrated salt and concentrated solution, cool the concentrated solution to 10°C, and separate the solid and liquid to obtain cooling salt and purified solution.

[0058] Step 5. Add a sodium carbonate solution with a concentration of 300 g / L to the purified liquid and react for 30 min, collect the precipitate, wash with water, and dry to obtain a lithium carbonate product. (That is, the difference from Example 2 is that 150 g / t of the inhibitor (a mixture of starch, dextrin and tartaric acid in a mass ratio of 1:2:1) is replaced with 150 g / t of starch, and 180 g / t of the collector (a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1:1.5:1.5) is replaced with 180 g / t of sodium dodecyl sulfate).

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A comprehensive recycling method for sedimentary lithium resources, characterized in that: The following steps are involved: Step 1. crushing, grinding and sieving the sedimentary lithium ore to obtain finely ground minerals; Step 2. reverse flotation the ground mineral to obtain flotation concentrate and flotation tailings; Step 3. The flotation concentrate is subjected to sulfuric acid aging and water leaching in sequence to obtain a lithium-containing leaching solution; Step 4. purifying and removing impurities from the lithium-containing leaching solution to obtain a purified solution; Step 5. adding sodium carbonate to the purified liquid to react, collecting the precipitate, and obtaining lithium carbonate; The depressant used in the flotation is a mixture of starch, dextrin and tartaric acid in a mass ratio of 1: (1-3): (0.5-2), and the collector is a mixture of coconut amine, sodium dodecyl sulfate and sodium oleate in a mass ratio of 1: (1-2.5): (0.5-1.5).

2. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: The grade of Li2O in the sedimentary lithium ore is 0.1% to 0.6%.

3. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: The dosage of the inhibitor is 80-160 g / t, and the dosage of the collector is 100-180 g / t.

4. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: During reverse flotation, the pH value of the reverse flotation system is 7.5-8.

5. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: The mass concentration of sulfuric acid used in the sulfuric acid aging is 70-80%; the temperature of the sulfuric acid aging is 130-160° C., and the time is 50-80 minutes.

6. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: The purification and impurity removal of the leachate is specifically as follows: first, a hydrogen peroxide solution is added to the lithium-containing leachate to oxidize ferrous ions into ferric ions, and then a sodium hydroxide solution is added to adjust the pH of the reaction system to 12, so that the iron forms ferric hydroxide precipitation; after filtering the precipitation, the pH of the reaction solution 1 is adjusted to 7 to form aluminum hydroxide precipitation; after filtering the precipitation, the pH of the reaction solution 2 is adjusted to 6-7, sodium oxalate is added to the reaction solution to form calcium oxalate precipitation, and after filtering the precipitation, the reaction solution 3 is concentrated to obtain concentrated salt and concentrated solution, the concentrated solution is cooled to 10-20°C, and solid-liquid separation is performed to obtain cooling salt and purified solution.

7. The comprehensive recycling method of sedimentary lithium resources according to claim 1, characterized in that: After collecting the precipitate, the method further includes the steps of washing and drying the precipitate.