Comprehensive utilization process for kaolin tailings

Abstract

A comprehensive utilization process for kaolin tailings. The process comprises: scrubbing kaolin tailings; enabling the scrubbed kaolin slurry to pass through a 5 mm linear screen, using +5 mm waste stone as aggregate, classifying the -5 mm fraction into the 2-5 mm fraction, the 0.1-2 mm fraction and the -0.1 mm fraction; grinding the 2-5 mm fraction and then performing classification, returning the +0.6 mm fraction for re-grinding, classifying the -0.6 mm fraction to remove the -0.045 mm slimes, performing magnetic separation on the 0.045-0.6 mm fraction to obtain magnetic separation concentrate, performing 1-2 stages of high-intensity magnetic separation on the magnetic separation concentrate to obtain high-intensity magnetic concentrate, performing heating and reagent-assisted scrubbing on the high-intensity magnetic concentrate, and then washing to remove residual reagent and slimes to obtain first-grade photovoltaic glass sand and classified fine sand; classifying the 0.1-2 mm fraction, grinding and sieving the +0.6 mm fraction until the faction is ground to -0.6 mm, performing gravity separation on the -0.6 mm fraction by means of a spiral chute to obtain heavy mineral and light mineral, performing 2-3 stages of magnetic separation on the light mineral to obtain magnetic concentrate and then performing flotation to obtain mica, classifying products in a flotation cell and desliming, classifying the -0.1 mm fraction as fine sand, performing heating and reagent-assisted scrubbing on the 0.1-0.6 mm fraction, and then washing to remove residual reagent and slime to obtain second-grade photovoltaic glass sand. The process achieves higher product yield and superior product quality indicators.

Description

A comprehensive utilization process for kaolin tailings Technical Field

[0001] This invention relates to the field of non-metallic mineral deep processing technology, specifically to a comprehensive utilization process for kaolin tailings. Background Technology

[0002] Kaolin is a hydrous aluminosilicate composed of various minerals, with kaolinite and hydrous kaolinite being the basic mineral components. Due to its excellent physicochemical properties, including plasticity, dispersibility, suspension properties, electrical insulation, refractoriness, high whiteness, low hardness, and acid resistance, kaolin has a wide range of applications in ceramics, papermaking, coatings, plastics, rubber, chemicals, petroleum refining, electronics, paints, inks, refractory materials, pharmaceuticals, cosmetics, pesticides, metallurgy, military, and aerospace industries.

[0003] my country has limited high-quality kaolin resources. The vast majority of kaolin ore is associated with various minerals, especially sandy kaolin from the south, whose mineral composition generally consists of kaolinite, quartz, feldspar, mica, and small amounts of metallic minerals. The tailings yield of sandy kaolin is 70%–80%, generating tens of millions of tons of kaolin tailings during production, and this amount is increasing annually. The large-scale stockpiling of kaolin tailings pollutes the environment, disrupts the ecological balance, and wastes resources.

[0004] The comprehensive utilization of kaolin tailings mainly involves the comprehensive recovery of minerals such as quartz, mica, and feldspar from the tailings. With the rapid development of the photovoltaic new energy industry, the demand for high-quality photovoltaic glass sand has increased significantly. The purification and processing of kaolin tailings to prepare photovoltaic glass sand has become a research hotspot. Existing technology CN112892852B discloses "A method for preparing silica sand for photovoltaic glass from kaolin tailings," which processes and purifies 1-5mm particle sizes in kaolin tailings to obtain silica sand with SiO2 99.5-99.7%, Al2O3 0.1-0.2%, and Fe2O3 0.0090-0.010%, but the yield is only 14%-18%. Existing technology CN110201791B discloses "A method for comprehensive utilization of sandy kaolin tailings containing tourmaline, muscovite, and quartz sand," which obtains ordinary flat glass quartz sand, but fails to meet the requirements for photovoltaic glass sand.

[0005] Current technology typically involves feeding all the mixed particle sizes of kaolin tailings into grinding mills. The -0.6mm grinding product is then deslimed, while the 0.1-0.6mm particles are purified and recycled as quartz sand through processes such as magnetic separation, flotation, and acid leaching. However, grinding the mixed particle sizes results in two problems: firstly, the -0.1mm fine sand has a complex composition and lower quality, leading to lower overall utilization value; secondly, the large +5mm particles, heavily disseminated with iron, are ground into the 0.1-0.6mm range, increasing the difficulty of purification.

[0006] Therefore, in order to address the above problems, this invention provides a comprehensive utilization process for kaolin tailings, so as to achieve more efficient and lower-cost recovery of quartz sand from kaolin tailings, resulting in higher product yield and better product indicators. Summary of the Invention

[0007] The purpose of this invention is to provide a comprehensive utilization process for kaolin tailings, so as to realize the high-value utilization of kaolin tailings.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A comprehensive utilization process for kaolin tailings includes the following steps:

[0010] (1) The kaolin tailings were scrubbed;

[0011] (2) After scrubbing, the kaolin slurry is passed through a 5mm linear screen. The waste stone with a thickness of +5mm is used as sand and gravel, and the waste stone with a thickness of -5mm is graded into 2-5mm, 0.1-2mm and -0.1mm.

[0012] (3) 2-5mm particle size grinding and classification, +0.6mm is returned for regrinding, -0.6mm is classified to remove -0.045mm tailings, 0.045-0.6mm is subjected to a first-stage magnetic separation to obtain magnetic concentrate, the magnetic concentrate is subjected to 1-2 stages of strong magnetic separation to obtain strong magnetic concentrate, the strong magnetic concentrate is subjected to heated and chemically treated scrubbing, and after scrubbing, it is subjected to de-chemical and desliming washing to obtain first-grade photovoltaic glass sand and graded fine sand;

[0013] (4) The 0.1-2mm particle size is classified, and the +0.6mm particle size is ground and screened until all particles are ground to -0.6mm. The -0.6mm particles are subjected to gravity separation in a spiral sluice to obtain heavy minerals and light minerals. The light minerals are subjected to 2-3 stages of magnetic separation to obtain magnetic concentrate. The magnetic concentrate is floated to obtain mica. The froth product is fine mica product. The product in the flotation cell is classified and deslimed. The -0.1mm particle size is classified as fine sand, which is a raw material for daily ceramics or glass fiber. The 0.1-0.6mm particle size is heated and treated with chemicals for scrubbing. After scrubbing, it is detreated and deslimed to obtain secondary photovoltaic glass sand.

[0014] Preferably, in step (1), the kaolin tailings are 50% to 60% sludge and the sludge washing time is 10 to 30 minutes.

[0015] Preferably, in step (2), the -0.1mm after the -5mm grading is the original -0.1mm tailings, which are mainly composed of kaolinite, feldspar, mica, quartz, etc., and can be used for building ceramics.

[0016] Preferably, in step (3), the magnetic separation intensity is 0.5 to 0.7 T; the strong magnetic separation intensity is 1.2 to 1.4 T.

[0017] Preferably, in step (3), the scrubbing temperature of the strong magnetic concentrate for heating and chemical scrubbing is 50℃~80℃, the scrubbing concentration is 50%~60%, the scrubbing time is 2~4 hours, and the scrubbing agent is selected from one or more of H2SO4, HF, H2C2O4, and HCl, and the total acid dosage is 5~15kg / t.

[0018] Preferably, in step (3), the SiO2 content of the primary photovoltaic glass sand is greater than 99.5%, and the Fe2O3 content is less than 50ppm; the SiO2 content of the graded fine sand is greater than 99%, and the Fe2O3 content is less than 200ppm, and the fine sand can be further processed into silicon micro powder products.

[0019] Preferably, in step (4), heavy minerals such as rutile, ilmenite, zircon, and tourmaline are comprehensively recovered.

[0020] Preferably, in step (4), the magnetic separation intensity is 0.5 to 1.6T; the pH of the magnetic concentrate slurry is adjusted to 3 to 4 with sulfuric acid; and dodecylamine is used to float mica, with a dodecylamine dosage of 100 to 300 g / t.

[0021] Preferably, in step (4), the scrubbing temperature of the 0.1-0.6mm particle size heated and doped scrubbing is 50-80℃, the scrubbing concentration is 50%-60%, the scrubbing time is 3-5 hours, and the scrubbing agent is selected from one or more of H2SO4, HF, H2C2O4, and HCl, and the total acid dosage is 10-30 kg / t.

[0022] Preferably, in step (4), the SiO2 content of the secondary photovoltaic glass sand is greater than 99.3%, and the Fe2O3 content is 80-100ppm.

[0023] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0024] In this invention, kaolin tailings are first subjected to high-concentration scrubbing, followed by grading. Large particles (+5mm) with high iron content are discarded directly. Particles of 2-5mm and 0.1-2mm are ground separately to obtain different grades of quartz sand. The original -0.1mm particles and the -0.1mm particles produced by grinding are processed separately to obtain high-quality graded fine sand, increasing the added value of the product. Grading can achieve a higher yield of photovoltaic sand and a higher quality photovoltaic sand product. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0026] Figure 1 is a process flow diagram of the comprehensive utilization of kaolin tailings in Embodiment 1 of the present invention. Detailed Implementation

[0027] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0028] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0029] Example 1

[0030] Referring to Figure 1, this embodiment provides a comprehensive utilization process for kaolin tailings. This embodiment uses kaolin tailings from a certain kaolin mine in Guangdong Province. The raw ore contains 90% quartz, 2% kaolinite, 4% feldspar, 3% mica, and 1% other components. The specific steps include the following:

[0031] (1) Kaolin tailings were scrubbed with a scrubbing concentration of 55% for 30 minutes.

[0032] (2) After scrubbing, the kaolin slurry is passed through a 5mm linear screen. The waste stone of +5mm is used as sand and gravel, and the waste stone of -5mm is graded into 2-5mm, 0.1-2mm and -0.1mm. The -0.1mm is mainly composed of kaolinite, feldspar, mica, quartz and other materials.

[0033] (3) 2-5mm particle size grinding and classification, +0.6mm is returned for regrinding, -0.6mm is classified to remove -0.045mm tailings, 0.045-0.6mm is subjected to a first-stage magnetic separation to obtain magnetic concentrate with a magnetic separation intensity of 0.7T; the magnetic concentrate is subjected to two-stage strong magnetic separation to obtain strong magnetic concentrate with a strong magnetic separation intensity of 1.4T; the strong magnetic concentrate is subjected to heated and chemically treated scrubbing at a temperature of 70℃, a scrubbing concentration of 55%, and a scrubbing time of 3 hours. The scrubbing agent is selected from one or more of H2SO4, HF, H2C2O4, and HCl, and the total acid dosage is 10kg / t; after scrubbing, the agent is removed and the mud is washed to obtain first-grade photovoltaic glass sand and graded fine sand;

[0034] (4) The 0.1-2mm particle size is classified, and the +0.6mm particle size is ground and screened until all particles are ground to -0.6mm. The -0.6mm particles are then subjected to spiral sluice gravity separation to obtain heavy and light minerals. The heavy minerals are comprehensively recovered, including rutile, ilmenite, zircon, and tourmaline. The light minerals are subjected to three-stage magnetic separation to obtain magnetic concentrate. The intensity of the first stage magnetic separation is 0.7T, and the intensity of the second and third stages magnetic separation is 1.4T. The magnetic concentrate is slurry-adjusted with sulfuric acid to pH=4, and then subjected to flotation to obtain... Mica, the foam product is a fine mica product. The product in the flotation cell is classified and deslimed. The -0.1mm particle size is classified as fine sand, which is a raw material for daily-use ceramics or glass fiber. The 0.1-0.6mm particle size is heated and chemically scrubbed at a scrubbing temperature of 70℃, a scrubbing concentration of 55%, and a scrubbing time of 5 hours. The scrubbing agent is H2SO4 + H2C2O4, and the total acid dosage is 20kg / t. After scrubbing, the product is deslimed and washed to obtain secondary photovoltaic glass sand.

[0035] In this embodiment, the yield of primary photovoltaic sand was 11.87%, the SiO2 content was 99.7%, and the Fe2O3 content was 35ppm. The yield of secondary photovoltaic sand was 52.87%, the SiO2 content was 99.3%, and the Fe2O3 content was 90ppm.

[0036] Example 2

[0037] This embodiment provides a comprehensive utilization process for kaolin tailings. The kaolin tailings in this embodiment are from a kaolin tailings mine in Guangxi. The raw ore contains 87% quartz, 2% kaolinite, 3% feldspar, 7% mica, and 1% other components. The specific steps include the following:

[0038] (1) Kaolin tailings were scrubbed with a scrubbing concentration of 60% for 20 minutes;

[0039] (2) After scrubbing, the kaolin slurry is passed through a 5mm linear screen. The waste stone of +5mm is used as sand and gravel, and the waste stone of -5mm is graded into 2-5mm, 0.1-2mm and -0.1mm. The -0.1mm is mainly composed of kaolinite, feldspar, mica, quartz and other materials.

[0040] (3) 2-5mm particle size grinding and classification, +0.6mm is returned for regrinding, -0.6mm is classified to remove -0.045mm tailings, 0.045-0.6mm is subjected to a first-stage magnetic separation to obtain magnetic concentrate with a magnetic separation intensity of 0.6T; the magnetic concentrate is subjected to two-stage strong magnetic separation to obtain strong magnetic concentrate with a strong magnetic separation intensity of 1.4T; the strong magnetic concentrate is subjected to heated and chemically treated scrubbing at a temperature of 70℃, a scrubbing concentration of 55%, and a scrubbing time of 3 hours. The scrubbing agent is HF+H2C2O4, and the total acid dosage is 9kg / t; after scrubbing, the agent is removed and the mud is removed to obtain first-grade photovoltaic glass sand and graded fine sand;

[0041] (4) The 0.1-2mm particle size is classified, and the +0.6mm particle size is ground and screened until all are ground to -0.6mm. The -0.6mm particle size is then subjected to spiral sluice gravity separation to obtain heavy minerals and light minerals. The heavy minerals are comprehensively recovered, including rutile, ilmenite, zircon, tourmaline, etc. The light minerals are subjected to two-stage magnetic separation to obtain magnetic concentrate with a magnetic separation intensity of 1.3T. The magnetic concentrate is slurryed with sulfuric acid to pH=3. The magnetic concentrate is then floated to obtain mica. The foam product is fine mica. The product in the flotation cell is classified and deslimed. The -0.1mm particle size is classified as fine sand, which is a raw material for daily ceramics or glass fiber. The 0.1-0.6mm particle size is heated and treated with chemicals for scrubbing. The scrubbing temperature is 70℃, the scrubbing concentration is 55%, and the scrubbing time is 5 hours. The scrubbing agent is H2SO4, and the total acid dosage is 18kg / t. After scrubbing, the product is de-treated and deslimed to obtain secondary photovoltaic glass sand.

[0042] In this embodiment, the yield of primary photovoltaic sand was 13.56%, with SiO2 content of 99.5% and Fe2O3 content of 50ppm; the yield of secondary photovoltaic sand was 46.78%, with SiO2 content of 99.3% and Fe2O3 content of 90-100ppm; and the yield of mica product was 7.45%, with K2O content of 9.43% and Fe2O3 content of 1.45%.

[0043] Example 3

[0044] This embodiment provides a comprehensive utilization process for kaolin tailings. The kaolin tailings used in this embodiment are from an Australian ore source. The original ore contains 92% quartz, 3% kaolinite, 5% mica, and 1% other components. The specific steps include:

[0045] (1) Kaolin tailings were scrubbed with a scrubbing concentration of 55% for 30 minutes.

[0046] (2) After scrubbing, the kaolin slurry is passed through a 5mm linear screen. The waste stone of +5mm is used as sand and gravel, and the waste stone of -5mm is graded into 2-5mm, 0.1-2mm and -0.1mm. The -0.1mm is mainly composed of kaolinite, feldspar, mica, quartz and other materials.

[0047] (3) 2-5mm particle size grinding and classification, +0.6mm is returned for regrinding, -0.6mm is classified to remove -0.045mm tailings, 0.045-0.6mm is subjected to a first-stage magnetic separation to obtain magnetic concentrate with a magnetic separation intensity of 0.5T; the magnetic concentrate is subjected to two-stage strong magnetic separation to obtain strong magnetic concentrate with a strong magnetic separation intensity of 1.4T; the strong magnetic concentrate is subjected to heated and chemically treated scrubbing at a temperature of 70℃, a scrubbing concentration of 60%, and a scrubbing time of 3 hours. The scrubbing agent is H2C2O4, and the total acid dosage is 10kg / t; after scrubbing, the reagent is removed and the mud is removed by washing to obtain first-grade photovoltaic glass sand and graded fine sand;

[0048] (4) The 0.1-2mm particle size is classified, and the +0.6mm particle size is ground and screened until all particles are ground to -0.6mm. The -0.6mm particles are then subjected to spiral sluice gravity separation to obtain heavy and light minerals. The heavy minerals are comprehensively recovered, including rutile, ilmenite, zircon, and tourmaline. The light minerals are subjected to three stages of magnetic separation to obtain magnetic concentrate. The magnetic field strength of the first stage is 0.5T, and the magnetic separation strength of the second and third stages is 1.2T. The magnetic concentrate is adjusted to pH 4 with sulfuric acid, and then subjected to flotation to obtain... The product from the flotation tank is fine mica, and the product is classified and deslimed in the flotation cell. The first stage is the 0.1mm particle size classification of fine sand, which is a raw material for daily-use ceramics or glass fiber. The second stage is the 0.1-0.6mm particle size classification, which involves heated and chemically treated scrubbing at 70℃, a scrubbing concentration of 55%, and a scrubbing time of 5 hours. The scrubbing agent used is H2SO4 + H2C2O4, with a total acid dosage of 19 kg / t. After scrubbing, the product undergoes desliming and dechemical washing to obtain secondary photovoltaic glass sand.

[0049] In this embodiment, the yield of primary photovoltaic sand was 20.56%, with SiO2 content of 99.5% and Fe2O3 content of 45ppm; the yield of secondary photovoltaic sand was 48.33%, with SiO2 content of 99.4% and Fe2O3 content of 80-100ppm; and the yield of mica product was 4.78%, with K2O content of 9.07% and Fe2O3 content of 2.45%.

[0050] Compared with the prior art, the present invention achieves higher product yield and better product indicators.

[0051] In summary, the kaolin tailings of this invention are first subjected to high-concentration scrubbing, followed by grading. Large particles (+5mm) with high iron content are discarded directly. Particles of 2-5mm and 0.1-2mm are processed separately through grinding to obtain quartz sand of different grades. The original -0.1mm particles and the -0.1mm particles produced by grinding are processed separately to obtain high-quality graded fine sand, increasing the added value of the product. Grading can achieve a higher yield of photovoltaic sand and a higher quality photovoltaic sand product.

[0052] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A process for the comprehensive utilization of kaolin tailings, characterized by, Includes the following steps: (1) The kaolin tailings were scrubbed; (2) After scrubbing, the kaolin slurry is passed through a 5mm linear screen. The waste stone with a thickness of +5mm is used as sand and gravel, and the waste stone with a thickness of -5mm is graded into 2-5mm, 0.1-2mm and -0.1mm. (3) 2-5mm particle size grinding and classification, +0.6mm is returned for regrinding, -0.6mm is classified to remove -0.045mm tailings, 0.045-0.6mm is subjected to a first-stage magnetic separation to obtain magnetic concentrate, the magnetic concentrate is subjected to 1-2 stages of strong magnetic separation to obtain strong magnetic concentrate, the strong magnetic concentrate is subjected to heated and chemically treated scrubbing, and after scrubbing, it is subjected to de-chemical and desliming washing to obtain first-grade photovoltaic glass sand and graded fine sand; (4) The 0.1-2mm particle size is classified, and the +0.6mm particle size is ground and screened until all of them are ground to -0.6mm. The -0.6mm particle size is subjected to spiral sluice gravity separation to obtain heavy minerals and light minerals. The light minerals are subjected to 2-3 stages of magnetic separation to obtain magnetic concentrate. The magnetic concentrate is floated to obtain mica. The product in the flotation cell is classified and deslimed. The -0.1mm particle size is classified as fine sand; the 0.1-0.6mm particle size is heated and treated with chemicals for scrubbing. After scrubbing, it is detreated and deslimed to obtain secondary photovoltaic glass sand.

2. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (1), the kaolin tailings are scrubbed with a concentration of 50% to 60% and a scrubbing time of 10 to 30 minutes.

3. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (2), the -0.1mm after the -5mm grading is the original -0.1mm tailings, which mainly consists of kaolinite, feldspar, mica, quartz, etc.

4. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (3), the magnetic separation intensity is 0.5 to 0.7 T; the strong magnetic separation intensity is 1.2 to 1.4 T.

5. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (3), the scrubbing temperature of the strong magnetic concentrate is 50℃~80℃, the scrubbing concentration is 50%~60%, the scrubbing time is 2~4 hours, and the scrubbing agent is selected from one or more of H2SO4, HF, H2C2O4, and HCl, with a total acid dosage of 5~15kg / t.

6. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (3), the SiO2 content of the first-grade photovoltaic glass sand is greater than 99.5%, and the Fe2O3 content is less than 50ppm; the SiO2 content of the graded fine sand is greater than 99%, and the Fe2O3 content is less than 200ppm. This fine sand can be further processed into silicon micro powder products.

7. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (4), heavy minerals such as rutile, ilmenite, zircon, and tourmaline are comprehensively recovered.

8. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (4), the magnetic separation intensity is 0.5 to 1.6T; the pH of the magnetic concentrate is adjusted to 3 to 4 with sulfuric acid; dodecylamine is used for mica flotation, and the dodecylamine dosage is 100 to 300 g / t.

9. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (4), the scrubbing temperature for the 0.1-0.6mm particle size heated and treated scrubbing is 50-80℃, the scrubbing concentration is 50%-60%, the scrubbing time is 3-5 hours, and the scrubbing agent is selected from one or more of H2SO4, HF, H2C2O4, and HCl, with a total acid dosage of 10-30 kg / t.

10. A process for the comprehensive utilization of kaolin tailings according to claim 1, characterized in that, In step (4), the SiO2 content of the secondary photovoltaic glass sand is greater than 99.3%, and the Fe2O3 content is 80-100ppm.

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