Method for preparing high-purity quartz from graphite tailings

Abstract

The invention relates to a method for preparing high-purity quartz by using graphite tailings, which is characterized by comprising the following steps: (1) feeding the graphite tailings into a flotation machine, adjusting the pH value to 2-4 by using sulfuric acid, and adding an inhibitor for flotation; (2) dehydrating and drying the flotation tailings, uniformly mixing the flotation tailings with a mineralizing agent, and then feeding the mixture into a high-temperature kiln for primary calcination; (3) feeding a calcined product into a cold water pool for water quenching, and then performing acid leaching with oxalic acid; (4) after acid leaching is finished, washing and drying a product, uniformly mixing the product with a mineralizing agent, and feeding the mixture into a high-temperature kiln for secondary calcination; (5) immediately feeding a calcined product into a cold water tank for water quenching, then crushing to-200 meshes, and then performing acid leaching by using mixed acid; and (6) washing to be neutral, and drying. The method has the advantages that the quartz particles with the purity of 99.5-99.95% can be prepared from the graphite tailings, can be used as a raw material for preparing ultra-high-purity micro-powder quartz sand and can be applied to industries such as electronic information, photovoltaics, optical communication and electric light sources, and the resource utilization rate and the additional value of the graphite tailings are greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of solid waste resource utilization and relates to a method for preparing high-purity quartz by utilizing graphite tailings. Technical Background

[0002] Graphite beneficiation mainly adopts flotation process. Since the graphite grade is generally less than 20%, a large amount of tailings will be produced in the production process, occupying a large amount of land resources. At the same time, the residual flotation reagents will also pollute the water and soil. Therefore, it is necessary to fully utilize the graphite tailings.

[0003] At present, the main methods for treating graphite tailings are: 1. Recovering vanadium-containing minerals, mainly recovering vanadium-containing mica through reverse flotation; 2. Using it as a building material, for various ceramic tiles or concrete aggregates; 3. Using conventional alkali fusion and acid leaching to prepare white carbon black; 4. Solidifying the graphite tailings into dry piles and backfilling. Summary of the invention

[0004] The purpose of the present invention is to make up for the deficiencies of the prior art and improve the utilization rate of resources, and to provide a method for preparing high-purity quartz using graphite tailings; the present invention can prepare quartz particles with a purity of 99.5-99.95%, which can be used as a raw material for preparing ultra-high-purity micro-powder quartz sand and applied to industries such as electronic information, photovoltaics, optical communications and electric light sources.

[0005] To achieve the above purpose, the technology of the present invention is as follows: A method for preparing high-purity quartz using graphite tailings, characterized by comprising the following steps: (1) The graphite tailings are fed into a flotation machine, the pH is adjusted to be between 2 and 4 by sulfuric acid, and 150-350 g / t of dodecylamine and 50-150 g / t of inhibitor are added for flotation operation; (2) After the flotation tailings are dehydrated and dried, they are evenly mixed with a mineralizer and sent to a high-temperature kiln for calcination at a temperature of 900°C to 1200°C for 3 to 5 hours; (3) immediately sending the product after calcination into a cold water pool for water quenching, then transferring it to a reactor, and acid leaching it with 10% oxalic acid in a volume ratio of 1:3-5 for 3-6 hours; (4) After the acid leaching is completed, the product is washed and dried (drying time is 4-8 hours at 120-180°C), mixed evenly with the mineralizer and sent into a high-temperature kiln for secondary calcination at a calcination temperature of 1200°C-1450°C for 5-8 hours; (5) After the calcination, the product is immediately sent to a cold water pool for water quenching, then crushed to -200 mesh and transferred to a reactor, and the crushed product is mixed with a mixture of 10% oxalic acid and 10% citric acid in a volume ratio of 1:2.5-4 for acid leaching, and the acid leaching time is 5-8 hours; (6) After acid leaching, the product is washed to neutrality and then dried (120-180°C for 4-8 hours) to obtain quartz particles with a purity of 99.5-99.95%.

[0006] Furthermore, the quartz content in the graphite tailings is 45% or more.

[0007] Furthermore, the inhibitor in step (1) is water glass or starch.

[0008] Furthermore, the mineralizers in step (2) and step (4) are limestone fine powder and iron scale powder, wherein the amount of limestone fine powder is 1.5-3% of the weight of the product, and the amount of iron scale powder is 0.5-1% of the weight of the product.

[0009] Furthermore, in step (5), the volume ratio of oxalic acid to citric acid is 1:1.

[0010] Compared with the prior art, the present invention has the following advantages: The process of the invention is simple, and the raw materials are widely available. Compared with conventional calcination and water quenching, the mineralizer helps the quartz crystal to undergo a reconstruction transformation, the volume expansion rate is larger, it is more conducive to the acid to enter the interior of the quartz, and the impurity removal effect is better, and the secondary mineralization-acid leaching further strengthens this effect. Quartz particles with a purity of 99.5-99.95% can be prepared, which can be used as a raw material for preparing ultra-high purity micro-powder quartz sand, and are applied to industries such as electronic information, photovoltaics, optical communications and electric light sources, greatly improving the resource utilization rate and added value of graphite tailings. Specific embodiments

[0011] A method for preparing high-purity quartz using graphite tailings, the specific implementation steps are as follows: Example

[0012] (1) The graphite tailings (quartz content 52%) are fed into a flotation machine, the pH is adjusted to be between 2 and 4 by sulfuric acid, and 200 g / t of dodecylamine and 100 g / t of water glass are added for flotation operation; (2) dehydrating and drying the tailings in step (1), adding 2% by weight of the tailings fine limestone powder and 0.6% by weight of the tailings iron scale powder to the tailings, mixing the mixture evenly, and sending the mixture into a high-temperature kiln for calcination at a temperature of 1000° C. for 5 h; (3) the product after calcination in step (2) is immediately sent to a cold water tank for water quenching, and then transferred to a reactor, and the product is acid-leached with oxalic acid having a mass concentration of 10% according to a volume ratio of the product to oxalic acid of 1:4, and the acid leaching time is 5 hours; (4) After the reaction in step (3) is completed, the product is washed and dried (120°C, 8h), 2.5% of the product weight of limestone fine powder and 0.8% of the product weight of iron scale powder are added, mixed evenly, and sent into a high-temperature kiln for secondary calcination at a calcination temperature of 1400°C and a calcination time of 6h; (5) the product after calcination in step (4) is immediately sent to a cold water tank for water quenching, then crushed to -200 mesh and transferred to a reactor, mixed with 10% oxalic acid and 10% citric acid in a volume ratio of 1:4 (the volume ratio of oxalic acid to citric acid is 1:1) for acid leaching, and the acid leaching time is 7 hours; (6) The product in step (5) is washed to neutrality and then dried (140° C., 6 h) to obtain quartz particles with a purity of 99.89%. Example

[0013] (1) The graphite tailings (quartz content 61%) are fed into a flotation machine, the pH is adjusted to be between 2 and 4 by sulfuric acid, and 250 g / t of dodecylamine and 80 g / t of starch are added for flotation operation; (2) dehydrating and drying the tailings in step (1), adding 2.5% of limestone powder and 0.5% of iron scale powder to the tailings, mixing evenly, and sending the mixture into a high-temperature kiln for calcination at a temperature of 900° C. for 4 h; (3) the product after calcination in step (2) is immediately sent to a cold water tank for water quenching, and then transferred to a reactor, and acid-leached with 10% oxalic acid at a volume ratio of 1:3 of product to oxalic acid for 6 hours; (4) After the reaction in step (3) is completed, the product is washed and dried (130°C, 7h), 3.0% limestone powder and 1% iron scale powder are added, mixed evenly, and sent into a high-temperature kiln for secondary calcination at a calcination temperature of 1450°C and a calcination time of 7h; (5) the product after calcination in step (4) is immediately sent to a cold water tank for water quenching, then crushed to -200 mesh and transferred to a reactor, and the product is mixed with a mixed solution of 10% mass concentration of oxalic acid and 10% mass concentration of citric acid (the volume ratio of oxalic acid to citric acid is 1:1) in a volume ratio of 1:3 for acid leaching treatment, and the acid leaching time is 8 hours; (6) The product in (5) is washed to neutrality and then dried (160°C, 5h) to obtain quartz particles with a purity of 99.93%. Example

[0014] (1) The graphite tailings (quartz content 45%) are fed into a flotation machine, the pH is adjusted to be between 2 and 4 by sulfuric acid, and 300 g / t of dodecylamine and 50 g / t of starch are added for flotation operation; (2) dehydrating and drying the tailings in step (1), adding 1.5% of the weight of the tailings fine limestone powder and 0.9% of the weight of the tailings iron scale powder and mixing the tailings evenly, and sending the mixture into a high-temperature kiln for calcination at a temperature of 950° C. for 4 h; (3) immediately sending the product after calcination in step (2) into a cold water tank for quenching, then transferring it to a reactor, and subjecting it to acid leaching with 10% oxalic acid at a volume ratio of product to oxalic acid of 1:4.5 for 5 hours; (4) After the reaction in step (3) is completed, the product is washed and dried (130°C, 6h), 2.5% of the product weight of limestone fine powder and 0.6% of iron scale powder are added, mixed evenly, and sent into a high-temperature kiln for secondary calcination at a calcination temperature of 1350°C and a calcination time of 8h; (5) the product after calcination in step (4) is immediately sent to a cold water tank for water quenching, then crushed to -200 mesh and transferred to a reactor, and the product is mixed with 10% oxalic acid and 10% citric acid in a volume ratio of 1:3.5 (the volume ratio of oxalic acid to citric acid is 1:1) for acid leaching, and the acid leaching time is 7.5 hours; (6) The product in step (5) is washed to neutrality and then dried (180° C., 4 h) to obtain quartz particles with a purity of 99.87%.

Claims

1. A method for preparing high-purity quartz using graphite tailings, characterized in that The following steps are involved: (1) The graphite tailings are fed into a flotation machine, the pH is adjusted to be between 2 and 4 by sulfuric acid, and 150-350 g / t of dodecylamine and 50-150 g / t of inhibitor are added for flotation operation; (2) After the flotation tailings are dehydrated and dried, they are evenly mixed with a mineralizer and sent to a high-temperature kiln for primary calcination; (3) immediately sending the product after calcination into a cold water pool for water quenching, then transferring it to a reactor, and acid leaching it with 10% oxalic acid in a volume ratio of 1:3-5 for 3-6 hours; (4) After the acid leaching is completed, the product is washed, dried, mixed evenly with the mineralizer and sent into a high-temperature kiln for secondary calcination; (5) After the calcination, the product is immediately sent to a cold water pool for water quenching, then crushed to -200 mesh and transferred to a reactor, and the crushed product is mixed with a mixture of 10% oxalic acid and 10% citric acid in a volume ratio of 1:2.5-4 for acid leaching, and the acid leaching time is 5-8 hours; (6) After acid leaching, the product is washed to neutrality and then dried to obtain quartz particles with a purity of 99.5-99.95%.

2. A method for preparing high-purity quartz using graphite tailings according to claim 1, characterized in that: The quartz content in the graphite tailings is 45% or more.

3. A method for preparing high-purity quartz using graphite tailings according to claim 1, characterized in that: The inhibitor in step (1) is water glass or starch.

4. A method for preparing high-purity quartz using graphite tailings according to claim 1, characterized in that: The temperature of the first calcination is 900°C-1200°C, and the calcination time is 3-5h; the temperature of the second calcination is 1200°C-1450°C, and the calcination time is 5-8h.

5. A method for preparing high-purity quartz using graphite tailings according to claim 1, characterized in that: The mineralizers in step (2) and step (4) are limestone powder and iron scale powder.

6. A method for preparing high-purity quartz using graphite tailings according to claim 5, characterized in that: The amount of limestone fine powder used is 1.5-3% of the product weight, and the amount of iron scale powder used is 0.5-1% of the product weight.

7. A method for preparing high-purity quartz using graphite tailings according to claim 1, characterized in that: In step (5), the volume ratio of oxalic acid to citric acid is 1:

1.

8. A method for preparing high-purity quartz from graphite tailings according to any one of claims 1 to 7, characterized in that: In the steps (4) and (6), the drying temperature is 120-180° C. and the drying time is 4-8 hours.