Comprehensive utilization method of sandy kaolin tailings

Abstract

The invention discloses a comprehensive utilization method of sandy kaolin tailings. The comprehensive utilization method comprises the following steps: step (1), screening the sandy kaolin tailings into two particle size grades of + 20-mesh coarse sand and-20-mesh fine sand; (2) grinding the coarse sand of + 20 meshes by adopting a high-aluminum ceramic ball mill, performing grading treatment after grinding, removing fine powder of-140 meshes to obtain a graded product, performing magnetic separation on the graded product, and removing magnetic minerals to obtain the low-iron quartz sand for the photovoltaic glass; and (3) the fine sand of-20 meshes is subjected to ore grinding through the high-aluminum ceramic ball mill, grading and reselection treatment are carried out after ore grinding, then magnetic separation is carried out, finally, obtained magnetic separation fine sand is subjected to direct flotation under the neutral condition, impurity minerals are removed, and the low-iron quartz sand for photovoltaic glass is obtained. And (4) carrying out magnetic separation, desliming, drying, grinding and grading treatment on-140-mesh fine sand generated in the treatment process of the + 20-mesh coarse sand and the-20-mesh fine sand to obtain the silica powder.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of sandy kaolin tailings, and particularly relates to a comprehensive utilization method of sandy kaolin tailings. Background Art

[0002] my country is rich in kaolin resources, with proven reserves of 2.91 billion tons, of which sandy kaolin resources account for about 60% of the proven reserves. Kaolin ore types can be divided into three types: hard kaolin, soft kaolin and sandy kaolin according to the texture, plasticity and sand content of kaolin ore. The sand content of sandy kaolin is greater than 50%. However, most of the current sandy kaolin processing companies only focus on the beneficiation, purification and deep processing of kaolin, and rarely recycle the large amount of tailings generated during the processing. Most of them are sold at low prices as construction sand, resulting in a waste of non-renewable resources. The main mineral component of sandy kaolin tailings is quartz, which contains a small amount of impurity minerals such as kaolinite, feldspar, mica, hematite, zircon and rutile, and is feasible for purification and preparation of low-iron quartz sand.

[0003] my country's solar photovoltaic power generation industry is developing rapidly. As an important component of solar cell modules, the demand for photovoltaic glass has increased significantly. Quartz sand is one of the main raw materials for the production of photovoltaic glass. About 0.71 tons of low-iron quartz sand are needed to produce one ton of photovoltaic glass, and its quality has an important impact on the quality of photovoltaic glass. However, there are currently few natural high-quality low-iron quartz sand sources in my country, which are mainly distributed in Guangdong Province, Guangxi Zhuang Autonomous Region, Anhui Province, Hainan Province and other places. In the future, with the growth of ultra-white glass production capacity for solar cells, high-quality quartz sand with limited production areas will become a relatively scarce resource. However, after the sorting of sandy kaolin in my country, a large amount of quartz-containing kaolin tailings are produced, which are not currently used efficiently. Therefore, the use of kaolin tailings to prepare low-iron quartz sand for photovoltaic glass is of great significance to the development of my country's photovoltaic industry.

[0004] The industrially mature purification processes for low-iron quartz sand for photovoltaic glass include physical methods such as grading, desludging, scrubbing, grinding, magnetic separation, gravity separation, ultrasonic scrubbing, flotation, and chemical methods such as pickling or acid leaching.

[0005] The current industry standard for photovoltaic sand quality requirements is "JC / T2314-2015 Silicon Raw Materials for Photovoltaic Glass", but there are deviations in the implementation process of various companies. The quality requirements of photovoltaic glass for photovoltaic sand are mainly reflected in: Fe2O3 content, TiO2 content and particle size. The most important thing is to control the content of Fe2O3. The obvious difference between quartz sand for photovoltaic glass and quartz sand for ordinary glass lies in the iron content. The Fe2O3 content of photovoltaic sand is required to be no more than 0.01% (the industry standard requires Fe2O3 content ≤ 0.008%). This is because iron oxides color the glass and affect the light transmittance of the glass. In addition, iron oxides cause a significant temperature gradient between the upper and lower layers of the glass liquid, resulting in difficulty in convection of the glass liquid in the melting furnace, increasing the difficulty of melting and clarification. Therefore, controlling the iron content in quartz sand is the key to photovoltaic sand production. The TiO2 content in photovoltaic sand is required to be no more than 300ppm, because titanium oxides will color the glass and reduce the light transmittance and transparency of the glass. The particle size and grading of photovoltaic sand will also affect the quality of photovoltaic glass. The particle size requirements are +0.71mm=0%; 0.71~0.1mm≥95%; -0.1mm≤5%.

[0006] At present, the sandy kaolin tailings utilization technology provides a method for using sandy kaolin tailings to prepare building sand, ordinary float glass sand, photovoltaic sand and quartz powder for TFT-LCD glass substrates. However, there are still some problems and shortcomings:

[0007] (1) Quartz sand grinding generally uses metal media (steel balls or steel rods) to grind the quartz sand. The grinding process causes "secondary iron pollution" on the surface of the quartz sand, making it difficult to prepare low-iron quartz sand by physical processing; at the same time, precise control of the grinding process cannot be achieved.

[0008] (2) In-depth mineralogical analysis of tailings of different particle sizes has not been conducted, resulting in insufficient understanding of the occurrence status of impurity minerals and impurity elements, and thus the inability to develop targeted purification process flows, resulting in a low level of utilization of sandy kaolin tailings resources.

[0009] (3) Flotation process is an effective means to remove impurities such as feldspar, mica, and iron-containing minerals in quartz sand, but the flotation environment must be acidic and organic reagents must be added for flotation. This process has high requirements for wastewater treatment. Acid leaching is a chemical mineral processing process that can greatly improve the removal rate of iron elements. Common acids include HF, H2SO4, HCl, HNO3, and H2C2O4. A large amount of ordinary sand in my country needs to be purified by acid leaching, which inevitably causes certain harm to the environment and workers' occupational health. Summary of the invention

[0010] In view of this, the main purpose of the present invention is to provide a method for comprehensive utilization of sandy kaolin tailings.

[0011] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0012] The embodiment of the present invention provides a method for comprehensive utilization of sandy kaolin tailings, comprising the following steps:

[0013] Step (1), screening the sandy kaolin tailings into two particle size levels of +20 mesh coarse sand and -20 mesh fine sand;

[0014] Step (2), grinding the +20 mesh coarse sand with a high-aluminum ceramic ball mill, performing classification after grinding, removing -140 mesh fine powder, obtaining a classified product, and then performing magnetic separation on the classified product to remove magnetic minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0015] Step (3), the -20 mesh fine sand is also ground using a high-aluminum ceramic ball mill, and after grinding, it is classified and re-selected, and then magnetically separated, and finally the obtained magnetically separated fine sand is subjected to positive flotation under neutral conditions to remove impurity minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0016] Step (4), subjecting the -140 mesh fine sand produced in the process of processing the +20 mesh coarse sand and -20 mesh fine sand to magnetic separation, desludging, drying, grinding and classification to obtain silicon micropowder.

[0017] In the above scheme, in step (1), the sandy kaolin tailings has a maximum particle size of 2 mesh, a moisture content of less than 10%, a SiO2 content of more than 95%, an Al2O3 content of less than 2%, and a Fe2O3 content of less than 0.3%.

[0018] In the above scheme, in the steps (2) and (3), the +20 mesh coarse sand is ground by a high-aluminum ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-aluminum ceramic balls have an Al2O3 content greater than 90%; the -20 mesh coarse sand is ground by a high-aluminum ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-aluminum ceramic balls have an Al2O3 content greater than 90%.

[0019] In the above scheme, in the step (3), during the grinding process, the product is classified by a cyclone, the underflow of the cyclone is fed to a high-frequency screen for screening, the +35 mesh product is returned to the ball mill for circulation grinding, the cyclone overflow and the product under the high-frequency screen are fed to a drum screen, the +35 mesh product on the drum screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for circulation grinding, the product under the drum screen is a -35 mesh qualified particle size product, the -35 mesh grinding product is hydraulically classified, the -140 mesh fine powder is removed, and a classified product is obtained; the classified product is then configured into a slurry with a concentration of 25% to 30%, and fed into a spiral chute for gravity separation; the gravity separation product is further magnetically separated and configured into a slurry with a concentration of 25% to 35%, the pH value of the slurry is adjusted to between 7 and 9, a cationic collector and sodium oleate are added, and neutral positive flotation is performed to obtain low-iron quartz sand for photovoltaic glass.

[0020] In the above scheme, in the step (2), the particle size of the grinding product is required to be less than 40 mesh during the grinding process, and the grinding particle size is controlled to be less than 40 mesh to achieve sufficient dissociation; the grinding product less than 40 mesh is hydraulically classified to remove -140 mesh fine powder to obtain a classified product; the classified product is configured into a mortar with a concentration of 25% to 30%, and fed into a spiral chute to remove heavy minerals to obtain a gravity separation product; the classified product is magnetically separated to remove magnetic minerals in the classified product to obtain low-iron quartz sand for photovoltaic glass.

[0021] In the above scheme, in steps (2) and (3), the particle size of the classified product is required to be controlled to have a content of -140 mesh less than 5%; the magnetic separation is divided into three stages, namely medium magnetic separation and two strong magnetic separations.

[0022] In the above scheme, in steps (2) and (3), the first stage is medium magnetic separation, the magnetic field strength is 0.3-0.6T, the second stage is strong magnetic separation, the magnetic field strength is 1.0-1.3T, and the third stage is magnetic separation, the magnetic field strength is 1.4-1.6T.

[0023] In the above scheme, in the step (4), the -140 mesh fine sand is subjected to magnetic separation with a magnetic field strength of 1.3 to 1.6 T to obtain a magnetic concentrate; the magnetic concentrate is desludged to remove the -400 mesh fine mud to obtain 140-400 mesh fine sand; the obtained fine sand is dehydrated by a belt vacuum filter to a moisture content of less than 10%, and then dried by a drum dryer to a moisture content of less than 0.5%; the dried fine sand is fed into a ball mill for dry grinding, the ground silicon micropowder is classified by a classifier, and the coarser particles are returned to the ball mill for re-grinding to form a closed loop to obtain silicon micropowder of the desired particle size specification.

[0024] In the above scheme, in the steps (2) and (3), according to Determine the optimal ball milling time t in the ball mill; where ρ is the density of quartz sand, Q is the total processing volume of the ball mill, V0 is the effective volume of the ball mill, C is the grinding concentration, R is the return sand ratio mark, v is the volume of slurry passing through the ball mill per unit time, and V1 is the volume of slurry in the ball mill.

[0025] Compared with the prior art, the present invention adopts a high-alumina ceramic ball mill to grind quartz sand, thereby avoiding the "secondary iron pollution" formed on the surface of quartz sand by iron-containing grinding media; by reasonably controlling the grinding particle size, the dissociation of quartz and gangue minerals is accurately controlled, and quartz sand is efficiently purified to prepare low-iron quartz sand for photovoltaic glass; a neutral flotation process is adopted to purify quartz sand by positive flotation, thereby realizing a green and environmentally friendly process to prepare low-iron quartz sand for photovoltaic glass, and solving the environmental and occupational health hazards brought about by the traditional process of acid flotation or chemical beneficiation; through process mineralogy research, the occurrence state of impurity minerals and impurity elements is identified, and different beneficiation processes are adopted for graded and classified comprehensive utilization, thereby improving the effective utilization rate and added value of kaolin tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to disclose a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A flow chart of a method for comprehensive utilization of sandy kaolin tailings is provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, article or device including the element.

[0031] The embodiment of the present invention provides a method for comprehensive utilization of sandy kaolin tailings, such as Figure 1 As shown, the following steps are included:

[0032] Step (1), screening the sandy kaolin tailings into two particle size levels of +20 mesh coarse sand and -20 mesh fine sand;

[0033] Step (2), grinding the +20 mesh coarse sand with a high-aluminum ceramic ball mill, performing classification after grinding, removing -140 mesh fine powder, obtaining a classified product, and then performing magnetic separation on the classified product to remove magnetic minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0034] Step (3), the -20 mesh fine sand is also ground using a high-aluminum ceramic ball mill, and after grinding, it is classified and re-selected, and then magnetically separated, and finally the obtained magnetically separated fine sand is subjected to positive flotation under neutral conditions to remove impurity minerals, thereby obtaining low-iron quartz sand for photovoltaic glass;

[0035] Step (4), subjecting the -140 mesh fine sand produced in the process of processing the +20 mesh coarse sand and -20 mesh fine sand to magnetic separation, desludging, drying, grinding and classification to obtain silicon micropowder.

[0036] Wherein, step (2) specifically includes:

[0037] (1) putting sandy kaolin tailings (maximum particle size 2 mesh, moisture content less than 10%, SiO2 content greater than 95%, Al2O3 content less than 2%, Fe2O3 content less than 0.3%) into a vibrating screen with a mesh size of 20 mesh for wet screening, removing fine sand of -20 mesh and obtaining coarse sand of +20 mesh;

[0038] (2) Grinding the +20 mesh coarse sand in a ball mill with high-alumina ceramic balls (Al2O3 content greater than 90%), with a grinding concentration of 45% to 60% and a ceramic ball filling rate of 40% to 45%. The grinding product is graded by a cyclone, and the cyclone underflow is fed to a high-frequency screen (mesh size 35 mesh) for screening, and the +35 mesh product is returned to the ball mill for circulation grinding; the cyclone overflow and the product under the high-frequency screen are fed to a drum screen (mesh size 35 mesh), and the +35 mesh product on the drum screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for circulation grinding, and the product under the drum screen is a qualified particle size product of -35 mesh;

[0039] (3) Hydraulically classify the -35 mesh grinding product, remove the -140 mesh fine powder, and obtain a classified product. The particle size of the classified product is required to control the -140 mesh content to less than 5%;

[0040] (4) The classified products are prepared into a slurry with a concentration of 25% to 30%, and fed into a spiral chute to remove heavy minerals to obtain a gravity separation product;

[0041] (5) Magnetic separation is performed on the classified products to remove magnetic minerals in the classified products to obtain magnetic separation concentrate. The magnetic separation is divided into three stages: the first stage is medium magnetic separation, the magnetic field strength is 0.3-0.6T, the second stage is strong magnetic separation, the magnetic field strength is 1.0-1.3T, and the third stage is magnetic separation, the magnetic field strength is 1.4-1.6T; quartz sand for photovoltaic glass is prepared (quality indicators are: 35-140 mesh greater than 95%, SiO2 content 99.3-99.7%, Al2O3 content less than 0.20%, Fe2O3 content 0.008%-0.010%).

[0042] Step (3) specifically includes:

[0043] (1) Wet-screening the sandy kaolin tailings through a vibrating screen to remove +20 mesh coarse sand and obtain -20 mesh fine sand;

[0044] (2) Grind the -20 mesh coarse sand in a ball mill with high alumina ceramic balls (Al2O3 content greater than 90%), with a grinding concentration of 45% to 60%, a ceramic ball filling rate of 40% to 45%, and a grinding product particle size of less than 40 mesh; (Because this particle size contains more mineral solid inclusions, the grinding particle size is controlled to less than 40 mesh to achieve sufficient dissociation).

[0045] (3) Hydraulically classify the ore products with a particle size less than 40 mesh, remove the fine powder with a particle size of -140 mesh, and obtain the classified products. The content of the particle size of -140 mesh in the classified products is required to be less than 5%;

[0046] (4) The classified products are prepared into a slurry with a concentration of 25% to 30%, and fed into a spiral chute to remove heavy minerals to obtain a gravity separation product;

[0047] (5) The classified products are subjected to magnetic separation to remove magnetic minerals in the classified products to obtain magnetic separation concentrate. The magnetic separation is divided into three stages: the first stage is medium magnetic separation, the magnetic field strength is 0.3-0.6T, the second stage is strong magnetic separation, the magnetic field strength is 1.0-1.3T, and the third stage is magnetic separation, the magnetic field strength is 1.4-1.6T; the magnetic separation concentrate (quality indicators are: 40-140 mesh greater than 95%, SiO2 content 99.0%-99.3%, Al2O3 content 0.3%-0.5%, Fe2O3 content 0.012%-0.020%) is prepared.

[0048] (6) The obtained magnetic concentrate is further subjected to positive flotation of quartz under neutral conditions to remove impurity minerals such as muscovite and feldspar. The specific method is as follows: the magnetic concentrate is prepared into a slurry with a concentration of 25% to 35%, and after stirring, the pH value of the slurry is adjusted with NaOH to control the pH value between 7 and 9, and then 50 to 100 g / t of a cationic collector (a mixture of dodecylamine and octadecylamine in a ratio of 1:1) and 100 to 200 g / t of sodium oleate are successively added, and the concentrate is obtained by aeration flotation (the quality indicators are: 40 to 140 mesh greater than 95%, SiO2 content 99.3 to 99.5%, Al2O3 content less than 0.20%, and Fe2O3 content 0.008% to 0.010%).

[0049] In order to prevent the first section magnetic separator of the vertical ring from being blocked, the first section magnetic separator is pulsed and flushed at a frequency of 100 times per minute.

[0050] The second and third sections of strong magnetic separation are without pulsating flushing; the medium boxes of the vertical ring magnetic separator are all composed of stainless steel rods with a diameter of 2mm.

[0051] Cationic amine collectors are prepared from amine and glacial acetic acid in a molar ratio of 1: 1. There are three flotation stages, and the amount of flotation collector is halved in each stage.

[0052] Step (4) specifically includes:

[0053] (1) The -140 mesh fine sand obtained in steps (2 and 3) is subjected to magnetic separation by a slurry magnetic separator with a magnetic field strength of 1.3 to 1.6 T.

[0054] (2) Desliming the magnetic concentrate to remove -400 mesh fine mud and obtain 140-400 mesh fine sand.

[0055] (3) dehydrating the obtained fine sand through a belt vacuum filter until the moisture content is less than 10%;

[0056] (4) drying the dehydrated fine sand in a drum dryer to obtain dry fine sand (water content less than 0.5%);

[0057] (5) The dried fine sand is fed into the ball mill for dry grinding. The ground silicon micropowder is sucked to the classifier for classification through the negative pressure generated by the fan. The coarser particles are returned to the ball mill for re-grinding to form a closed loop. The finer silicon micropowder is sucked to the cyclone collector for capture to obtain silicon micropowder. Silicon micropowders of different particle sizes can be produced by flexible adjustment of grinding and classification parameters.

[0058] Further, according to Determine the optimal ball milling time t in the ball mill; where ρ is the density of quartz sand, Q is the total processing volume of the ball mill, V0 is the effective volume of the ball mill, C is the grinding concentration, R is the return sand ratio mark, v is the volume of slurry passing through the ball mill per unit time, and V1 is the volume of slurry in the ball mill.

[0059] The slurry volume V1 in the ball mill is positively correlated with the effective volume V0 of the ball mill in step 2.

[0060] After determining the optimal ball milling time of the ore in the ball mill, we then conduct laboratory grinding tests to find the optimal grinding time. We use this time as a reference and compare the difference with the calculated optimal ball milling time. We make corrections based on the difference, which can accurately control the efficient operation of grinding operations in industrial production.

[0061] By measuring the operation time and total discharge volume of the ball mill, combined with the measured volume of slurry passing through the ball mill per unit time, the results are calculated and compared to determine whether the ore particles are continuously and without retention in the process from the feeding of the ball mill to the discharging port.

[0062] The volume v of slurry passing through the ball mill per unit time is multiplied by the operating time, and the result is the theoretical total discharge volume under that time. The continuity is determined by comparing it with the actual total discharge volume. If the actual value is smaller, it means discontinuity.

[0063] Quartz sand density ρ = 2.65t / m 3 For example, if the laboratory grinding test shows that the optimal time is t = 6min, then the grinding process parameters can be adjusted according to the formula:

[0064] (1) If V1 = 7.5 m 3 , under the conditions of C = 60%, R = 30%, the optimal processing capacity should be adjusted to Q = 55.3t / h;

[0065] (2) If V1 = 7.5 m 3 , R = 60%, Q = 55.3t / h, the optimal grinding concentration should be calculated according to the formula to be C = 68%;

[0066] (3) If V1 = 7.5 m 3Under the conditions of C=68%, Q=75t / h, the optimal return sand ratio should be calculated according to the formula to be R=17.9%.

[0067] Example: Taking a sandy kaolin tailings from a certain place in Guangdong as an example (I) Elemental analysis data of kaolin tailings particle size

[0068] Table 1 Chemical element analysis results of kaolin tailings in Guangdong

[0069]

[0070] As shown in Table 1, the quality of tailings of different particle sizes varies significantly. As the particle size decreases, the content of SiO2 in the tailings increases first and then decreases, while the impurity elements such as Al2O3, Fe2O3, TiO2, and K2O decrease first and then increase. The overall performance is that the coarse particle size of +20 mesh is of good quality, while the fine particle size of -20 mesh is of poor quality, indicating that the tailings have the potential for graded comprehensive utilization.

[0071] (II) Ore dressing results

[0072] (1) +20 mesh kaolin tailings beneficiation results

[0073] Test conditions:

[0074] (1) Process flow: “Grinding-Classification-Gravity Separation-Medium Magnetic (0.6T)-Strong Magnetic (1.3T)-Strong Magnetic (1.5T)”

[0075] (2) Grinding conditions: Grinding time 8 min, grinding product particle size 140-35 mesh greater than 95%.

[0076] (3) Magnetic separation conditions: medium magnetic separation has a pulsation of 100 times / min, and strong magnetic separation has no pulsation.

[0077] The test results are shown in the following table:

[0078] Serial number Sample name Sample No. Total yield / % <![CDATA[SiO2 / %]]> <![CDATA[Al2O3 / %]]> <![CDATA[Fe2O3 / %]]> 1 +20 mesh tailings MM1-1 44.6 99.37 0.46 0.0328 3 Graded underflow MM1-2 39.0 99.50 0.21 0.0241 4 Graded overflow MM1-3 5.6 98.46 2.20 0.0934 5 Gravity Concentrate MM1-4 38.4 99.51 0.20 0.0219 6 Gravity separation tailings MM1-5 0.6 96.24 0.85 0.1649 11 Medium Magnetic Concentrate MM1-6 36.9 99.55 0.18 0.0115 12 Medium magnetic tailings MM1-7 1.5 97.54 0.69 0.2778 15 Strong Magnetic 1 Concentrate MM1-8 35.8 99.60 0.16 0.0105 16 Strong magnetic 1 tailings MM1-9 1.1 98.93 0.83 0.0440 19 Strong Magnetic 2 Concentrate MM1-10 35.1 99.62 0.15 0.0093 20 Strong magnetic 2 tailings MM1-11 0.7 99.10 0.66 0.0707

[0079] (2)-20 mesh kaolin tailings beneficiation results

[0080] Test conditions:

[0081] (1) Process flow: “Grinding-Classification-Gravity Separation-Medium Magnetic (0.6T)-Strong Magnetic (1.3T)-Strong Magnetic (1.5T)”

[0082] (2) Grinding conditions: Grinding time 10 min, grinding product particle size 140-40 mesh greater than 95%.

[0083] (3) Magnetic separation conditions: medium magnetic separation has a pulsation of 100 times / min, and strong magnetic separation has no pulsation.

[0084] (4) Flotation conditions: pH 8.0, mixed amine 50 g / t, sodium oleate 100 g / t.

[0085] The test results are shown in the following table:

[0086]

[0087] (3) Preparation of ceramic glaze powder by grading fine sand

[0088] The +20 mesh coarse sand and -20 mesh fine sand are ground and classified to produce graded fine sand, with a total graded fine sand yield of 12.3%. The graded fine sand is magnetically separated by a slurry magnetic separator (magnetic field strength 1.4T), and the magnetic concentrate is subjected to "de-sludge-filtration dehydration-drying-grinding and classification" to obtain -325 mesh silicon micropowder. The specific indicators are shown in the table below. The quality meets the requirements of ceramic glaze powder. The graded fine sand is de-sludged to remove -400 mesh fine mud to prepare silicon micropowder for ceramic glaze.

[0089]

[0090]

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A method for comprehensive utilization of sandy kaolin tailings, It is characterized in that The following steps are involved: Step (1), screening the sandy kaolin tailings into two particle size levels of +20 mesh coarse sand and -20 mesh fine sand; Step (2), grinding the +20 mesh coarse sand with a high-aluminum ceramic ball mill, performing classification after grinding, removing -140 mesh fine powder, obtaining a classified product, and then performing magnetic separation on the classified product to remove magnetic minerals, thereby obtaining low-iron quartz sand for photovoltaic glass; Step (3), the -20 mesh fine sand is also ground using a high-aluminum ceramic ball mill, and after grinding, it is classified and re-selected, and then magnetically separated, and finally the obtained magnetically separated fine sand is subjected to positive flotation under neutral conditions to remove impurity minerals, thereby obtaining low-iron quartz sand for photovoltaic glass; Step (4), subjecting the -140 mesh fine sand produced in the process of processing the +20 mesh coarse sand and -20 mesh fine sand to magnetic separation, desludging, drying, grinding and classification to obtain silicon micropowder.

2. The method for comprehensive utilization of sandy kaolin tailings according to claim 1, It is characterized in that In the step (1), the sandy kaolin tailings has a maximum particle size of 2 mesh, a moisture content of less than 10%, and SiO 2 Content greater than 95%, Al 2 O 3 Content is less than 2%, Fe 2 O 3 The content is less than 0.3%.

3. The method for comprehensive utilization of sandy kaolin tailings according to claim 1 or 2, It is characterized in that In the steps (2) and (3), the +20 mesh coarse sand is ground with a high-aluminum ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-aluminum ceramic ball is Al 2 O 3 The content is greater than 90%; the -20 mesh coarse sand is ground with a high-aluminum ceramic ball mill, the grinding concentration is 45% to 60%, the ceramic ball filling rate is 40% to 45%, and the high-aluminum ceramic ball is Al 2 O 3 The content is greater than 90%.

4. The method for comprehensive utilization of sandy kaolin tailings according to claim 3, It is characterized in that In the step (3), during the grinding process, the product is classified by a cyclone, the underflow of the cyclone is fed to a high-frequency screen for screening, the +35 mesh product is returned to the ball mill for circulation grinding, the cyclone overflow and the product under the high-frequency screen are fed to a drum screen, the +35 mesh product on the drum screen is combined with the +35 mesh product on the high-frequency screen and returned to the ball mill for circulation grinding, the product under the drum screen is a -35 mesh qualified particle size product, the -35 mesh grinding product is hydraulically classified, the -140 mesh fine powder is removed, and the classified product is obtained; the classified product is then configured into a slurry with a concentration of 25% to 30%, and is fed into a spiral chute for gravity separation; the gravity separation product is further magnetically separated and configured into a slurry with a concentration of 25% to 35%, the pH value of the slurry is adjusted to between 7 and 9, a cationic collector and sodium oleate are added, and neutral positive flotation is performed to obtain low-iron quartz sand for photovoltaic glass.

5. The method for comprehensive utilization of sandy kaolin tailings according to claim 4, It is characterized in that In the step (2), the particle size of the grinding product is required to be less than 40 mesh during the grinding process, and the grinding particle size is controlled to be less than 40 mesh to achieve sufficient dissociation; the grinding product less than 40 mesh is hydraulically classified to remove -140 mesh fine powder to obtain a classified product; the classified product is configured into a mortar with a concentration of 25% to 30%, and fed into a spiral chute to remove heavy minerals to obtain a gravity separation product; the classified product is magnetically separated to remove magnetic minerals in the classified product to obtain low-iron quartz sand for photovoltaic glass.

6. The method for comprehensive utilization of sandy kaolin tailings according to claim 5, It is characterized in that In steps (2) and (3), the particle size of the classified product is required to be controlled to have a content of -140 mesh less than 5%; the magnetic separation is divided into three stages, namely medium magnetic separation and two strong magnetic separations.

7. The method for comprehensive utilization of sandy kaolin tailings according to claim 5, It is characterized in that In steps (2) and (3), the first stage is medium magnetic separation, the magnetic field strength is 0.3-0.6T, the second stage is strong magnetic separation, the magnetic field strength is 1.0-1.3T, and the third stage is magnetic separation, the magnetic field strength is 1.4-1.6T.

8. The method for comprehensive utilization of sandy kaolin tailings according to claim 7, It is characterized in that In the step (4), the -140 mesh fine sand is subjected to magnetic separation with a magnetic field strength of 1.3 to 1.6 T to obtain a magnetic concentrate; the magnetic concentrate is desludged to remove the -400 mesh fine mud to obtain 140-400 mesh fine sand; the obtained fine sand is dehydrated by a belt vacuum filter to a moisture content of less than 10%, and then dried by a drum dryer to a moisture content of less than 0.5%; the dried fine sand is fed into a ball mill for dry grinding, the ground silicon micropowder is classified by a classifier, and the coarser particles are returned to the ball mill for re-grinding to form a closed loop to obtain silicon micropowder of the desired particle size specification.

9. The method for comprehensive utilization of sandy kaolin tailings according to claim 8, It is characterized in that In the steps (2) and (3), according to Determine the optimal ball milling time t in the ball mill; where ρ is the density of quartz sand, Q is the total processing volume of the ball mill, and V 0 is the effective volume of the ball mill, C is the grinding concentration, R is the return sand ratio, v is the volume of slurry passing through the ball mill per unit time, V 1 is the volume of slurry in the ball mill.

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