A method for comprehensive utilization of weathered complex kaolin

Abstract

The present invention discloses a method for the comprehensive utilization of weathered complex kaolin. The method performs multi-gradient particle size classification on the weathered complex kaolin ore based on the order of quartz mineral particle size > feldspar mineral particle size > mica mineral particle size > kaolin particle size. The ore of different particle sizes is then subjected to magnetic separation, flotation, reverse flotation, and other methods to ultimately produce feldspar, quartz, mica, and kaolin products. The tailings produced in this process can meet the manufacturing requirements for silicate-based building materials. This method achieves the comprehensive utilization of multiple products from weathered complex kaolin.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive utilization of mineral resources, relates to the processing and utilization of weathered complex kaolin, and particularly relates to a method for comprehensive utilization of weathered complex kaolin. Background Art

[0002] Kaolin mineral resources undergo a series of chemical changes after being subjected to strong physical weathering and contamination by immersion in impure surface water (such as carbonated rainwater, river water, seawater and groundwater, etc.). A layer of soil is formed on the parent rock, the main mineral of which is kaolin, accompanied by some feldspar, quartz, mica and other minerals. Due to long-term exposure and weathering, weathered complex kaolin has many impurities and serious mineral mudification. When mining and utilizing weathered complex kaolin, most mines focus on the mining and utilization of single kaolin mineral products, and most of its associated minerals are directly discarded during mining due to problems such as many impurities, small particle size, complex mineral embedding, and difficulty in separation, resulting in a waste of useful minerals. The discarded tailings bring huge pressure to environmental protection. Therefore, there is an urgent need to provide a process method for the comprehensive utilization of weathered complex kaolin. Summary of the Invention

[0003] The present invention aims to provide a method for the comprehensive utilization of weathered complex kaolin. The method is primarily directed towards the enrichment of kaolin mineral products, while also allowing for the exploitation and utilization of other useful minerals. The remaining small amount of tailings can be used as a raw material for building materials, thereby achieving the comprehensive utilization of weathered complex kaolin.

[0004] The method for comprehensive utilization of weathered complex kaolin provided by the present invention comprises the following steps:

[0005] 1) adding weathered complex kaolin to water to form a slurry, then adding a dispersant to the slurry, and then stirring and scrubbing to obtain a scrubbed slurry;

[0006] 2) coarsely screening the slurry after scrubbing in step 1) to remove non-mineral impurities in the weathered complex kaolin, and then screening it using a high-frequency vibration fine screen to obtain an oversize material and an undersize material;

[0007] 3) Desliming the undersize material in step 2), controlling the sieve aperture diameter of the desliming equipment, and obtaining a coarse-grained oversize material and a fine-grained undersize material;

[0008] 4) subjecting the fine-grained undersize material obtained in step 3) to high-intensity magnetic separation to obtain non-magnetic minerals and magnetic products, wherein the non-magnetic minerals are kaolin products, and the magnetic products are used as raw materials for aerated bricks;

[0009] 5) The coarse-grained oversize material obtained in step 3) is subjected to one roughing and one or more flotation cleaning, and the final concentrate obtained is a mica product; the tailings obtained from the roughing are mixed with the middlings obtained from the cleaning, and are recorded as middlings 1;

[0010] 6) ball milling the oversize material obtained in step 2), and then desludging, controlling the sieve hole diameter of the desludging equipment to obtain a non-sludge portion and a sludge portion; the sieve hole diameter of the desludge equipment is consistent with the sieve hole diameter of the desludge equipment in step 3); the sludge portion is recorded as middling ore 2;

[0011] 7) The non-mud portion in step 6) is subjected to flotation with one roughing and six or more scavenging steps to obtain a quartz product; the froth products of the roughing and scavenging steps are mixed and recorded as middling ore 3;

[0012] 8) Mixing the middling ore 1 obtained in step 5), the middling ore 2 obtained in step 6), and the middling ore 3 obtained in step 7), adding a defoamer and a dispersant, and stirring uniformly, then subjecting the mixture to high-intensity magnetic separation to remove impurities, thereby obtaining a magnetic portion and a non-magnetic portion; subjecting the non-magnetic portion to multi-stage reverse flotation to remove impurities, ultimately obtaining a feldspar product and a reverse flotation foam product; and mixing the magnetic product with the reverse flotation foam product to serve as a raw material for aerated bricks.

[0013] Preferably, in step 1), the concentration of the slurry is 25% to 40%; the dispersant may be, for example, sodium hexametaphosphate, sodium carbonate, water glass, etc.; and the stirring and scrubbing process is performed at a stirring speed of 1200 to 2000 r / min and a stirring time of 7 to 10 min.

[0014] Preferably, in step 2), the mesh diameter of the sieve used for the coarse screening is 2-4 cm; and the non-mineral impurities are roots, branches, leaves, etc.

[0015] Preferably, in step 2), the mesh diameter of the high-frequency vibrating fine sieve is 0.15-0.3 mm.

[0016] Further preferably, in step 2), the mesh diameter of the high-frequency vibrating fine sieve is 0.17 mm.

[0017] The main component of the oversize material in step 2) is quartz.

[0018] Preferably, in step 3), the sieve hole diameter of the desludging equipment is controlled to be 0.03 mm to 0.05 mm.

[0019] Preferably, in step 4), the high-intensity magnetic separation is at least one rough magnetic separation and one or more fine magnetic separations, and the magnetic field intensity is controlled to be above 1.5T.

[0020] Preferably, in step 5), the pH of the flotation is 2-3, sodium hexametaphosphate and sodium fluorosilicate are used as a combined inhibitor, and dodecylamine is used as a collector.

[0021] Preferably, in step 6), the ball mill controls the grinding fineness to be 60% to 80% at a particle size of -0.074 mm.

[0022] Preferably, in step 7), the flotation is carried out by using hydrochloric acid + oxalic acid as adjusting agents to control the pH of the pulp to 2-3, using water glass as an inhibitor, cetyltrimethylammonium chloride as a collector, and pine oil as a foaming agent.

[0023] Preferably, in step 8), the stirring speed is 1200-2000 r / min, and the stirring time is 7-10 min.

[0024] Preferably, in step 8), the high-intensity magnetic separation is at least one magnetic roughing and one or more magnetic separations, and the magnetic field intensity is controlled at above 1.5 T; the multi-stage reverse flotation is one roughing and three or more scavengings, and sodium carbonate is used as an adjuster to adjust the pH of the slurry to 8-9, and potassium chloride and citric acid are combined in a mass ratio of (3-1): (0.6-0.3) as an inhibitor, and sodium oleate, benzohydroxamic acid and coconut amine are compounded in a mass ratio of (5-3): (3-1): (0.1-0.05) as a combined collector.

[0025] The principle and beneficial effects of the present invention are as follows: Quartz and feldspar silicate minerals are resistant to weathering and corrosion. During the weathering process of complex kaolin, quartz and feldspar minerals are difficult to weather and have coarser particles, while minerals such as mica and kaolin are more easily weathered and have finer particle sizes. This results in the particle size of quartz > feldspar > mica > kaolin in the original ore. Therefore, particle size classification of weathered complex kaolin is crucial for achieving comprehensive utilization of weathered complex kaolin.

[0026] This invention addresses the challenges of complex weathered kaolin, including high levels of impurities, fine mud, and complex mineral distribution. By designing a multi-gradient particle size classification process, magnetic separation, and flotation, the resulting product is feldspar, quartz, mica, and kaolin. This multi-gradient particle size classification technology is key to the comprehensive utilization of complex weathered kaolin. By adopting appropriate particle size levels and screening to process weathered complex kaolin, small-sized materials will not enter the ball mill with coarse particles, thereby reducing the grinding process capacity, saving energy consumption, and preventing over-grinding during the grinding process, which would affect the subsequent flotation process. In terms of process equipment, appropriate particle size classification is the process of initial enrichment after separating the quartz, kaolin, and feldspar products. This process uses simple methods, requires common equipment, and does not produce any pollution. After multi-gradient classification, the large-sized component is mainly quartz, the larger-sized component is mainly feldspar, and the small-sized component is mainly kaolin. The target minerals are then flotated and recovered in their respective particle size levels. The reagents used are more targeted, the dosage of various reagents is reduced, production costs are reduced, and the resulting products are of higher purity. Finally, the tailings produced in this process can meet the manufacturing conditions of silicate product building materials, realizing the comprehensive utilization of multiple products of weathered complex kaolin. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a process flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0028] Example 1

[0029] The weathered complex kaolin sample used in this example was obtained from a mine in Shaoguan, Guangdong. The sample consisted of sandy soil formed after the surface complex kaolin weathered. The sample was subjected to particle size classification, and the products of each particle size were analyzed using XRD. The quartz, feldspar, mica, and kaolin contents were roughly analyzed. The main results are shown in Table 1. Based on this, the weathered complex kaolin was particle-sized, and mineral enrichment and recovery were carried out for the different particle size ore, achieving comprehensive utilization of the weathered complex kaolin in multiple products.

[0030] Table 1 Analysis of particle size of weathered complex kaolin

[0031]

[0032] A full elemental analysis of the weathered complex kaolin sample used in this example revealed that the main elements were silicon, potassium, aluminum, iron, and the precious metal rubidium, with contents of 30.12%, 8.17%, 6.1%, 1.18%, and 0.027%, respectively. XRD results also revealed that the main minerals in the weathered complex kaolin were quartz, feldspar, kaolin, and mica, with contents of 40%, 15%, 30%, and 10%, respectively.

[0033] Weathered complex kaolin and water were added to a mixing barrel at a solid-liquid ratio of 1kg:2L. 500g / t of dispersant sodium carbonate was added, and the stirring speed was set to 1500r / min for high-speed stirring for 8 minutes. A sieve with a mesh diameter of 3cm was used to coarsely screen the stirred and scrubbed slurry. The sieve-surface impurities mainly consisted of non-mineral impurities such as branches and grass roots. The sieve-surface impurities were then finely screened using a high-frequency vibrating fine sieve with a mesh diameter of 0.17mm, obtaining a coarse particle size of +0.17mm on the sieve and a fine particle size of -0.17mm on the sieve.

[0034] The -0.17mm fine-particle size undersize was deslimed using a hydrocyclone, resulting in a controlled separation of +0.037mm and -0.037mm fractions, with the +0.037mm fraction accounting for approximately 80% and the -0.037mm fraction accounting for approximately 20%. The -0.037mm fraction was subjected to two rounds of high-intensity magnetic separation at a magnetic field strength of 1.5T, ultimately yielding a non-magnetic kaolin product and a magnetic product for use as a raw material for aerated bricks. The kaolin product's main specifications include an Al2O3 grade of 41.5%, a SiO2 grade of 51.5%, and a Fe2O3 grade of 1.23%, with a yield of 45.34%.

[0035] The above-mentioned +0.037mm particle size material was subjected to a flotation process consisting of one roughing and two concentrating steps. The pH of the roughing step was adjusted to 2-3 using sulfuric acid. A combined depressant of sodium hexametaphosphate and sodium fluorosilicate was used in both the roughing and concentrating steps, with a mass ratio of 1:2. Dodecylamine was used as the collector. The depressant dosage for the roughing step was 1000g / t, and the collector dosage was 40g / t. The first concentrating step used 800g / t, and the collector dosage was 20g / t. The second concentrating step used 500g / t, and the collector dosage was 15g / t. The final concentrate was a mica product. The tailings from the roughing step were mixed with the middlings from the concentrating step and are designated as middling 1.

[0036] The main indicators of mica products are: Al2O3 grade is 1.09%, SiO2 grade is 97.23%, Fe2O3 grade is 0.02%, and the yield reaches 7.40%.

[0037] The material above the coarse-size fraction of +0.17 mm was ball-milled for 8 minutes, resulting in a particle size of -0.074 mm reaching approximately 78%. The reground ore was deslimed using a hydrocyclone, yielding a +0.037 mm non-sludge fraction and a -0.037 mm slime fraction. The -0.037 mm slime fraction was designated as middling ore 2. The +0.037 mm non-sludge fraction underwent a flotation process consisting of one roughing run and six sweeping runs. During the roughing run, hydrochloric acid and oxalic acid were used as pH adjusters to maintain a pH of 2-3. The entire flotation process used water glass as a depressant, hexadecyltrimethylammonium chloride as a collector, and pine oil as a frother. The depressant dosage during the roughing run was 800 g / t, the collector dosage was 450 g / t, and the frother dosage was 40 g / t. For the first three scavenging runs, the inhibitor dosage was 600 g / t, the collector dosage was 300 g / t, and the frother dosage was 30 g / t. For the fourth and fifth scavenging runs, the inhibitor dosage was 400 g / t, the collector dosage was 200 g / t, and the frother dosage was 20 g / t. For the sixth scavenging run, no inhibitor was added, and the collector dosage was 150 g / t, with the frother dosage being 20 g / t. The final quartz product was obtained. The foam products from the roughing and scavenging runs were combined and designated as middling ore 3. The main specifications of the quartz product were: Al2O3 grade of 1.09%, SiO2 grade of 98.73%, Fe2O3 grade of 0.15%, and a yield of 19.14%.

[0038] The above-mentioned middlings 1, 2, and 3 were transferred to a mixing tank and vigorously stirred. 20g / t tributyl phosphate (a defoamer) and 500g / t sodium carbonate (a dispersant) were added, and the mixture was stirred at 1500r / min for 10 minutes. The agitated slurry then underwent a primary roughing and a secondary magnetic separation, with the magnetic field intensity maintained at above 1.5T to effectively remove iron-containing impurities. After the magnetic separations, the magnetic fractions from the two separations were used as the magnetic product, while the non-magnetic fraction was subjected to reverse flotation. The reverse flotation process consists of one roughing operation and three scavenging operations. Sodium carbonate is used during the roughing operation to adjust the pulp pH to 8-9. Potassium chloride and citric acid are used as a combined depressant in a mass ratio of 2:1, and sodium oleate, benzohydroxamic acid, and coconut amine are used as a combined collector in a mass ratio of 3:1:0.5. The combined depressant dosage is 1500 g / t and the combined collector dosage is 300 g / t during the roughing operation. During the first scavenging operation, the combined depressant dosage is 1200 g / t and the combined collector dosage is 300 g / t. During the second scavenging operation, the combined depressant dosage is 1000 g / t and the combined collector dosage is 200 g / t. During the third scavenging operation, the combined depressant dosage is 1000 g / t and the combined collector dosage is 200 g / t. The final product is feldspar. The magnetic product is mixed with the reverse flotation foam product to serve as a raw material for aerated bricks. The main indicators of feldspar products are: K2O grade of 18.27%, Al2O3 grade of 10.63%, SiO2 grade of 70.56%, Fe2O3 grade of 0.15%, and yield of 15.32%. The main indicators of aerated brick raw materials are: Al2O3 grade of 8.21%, SiO2 grade of 67.55%, Fe2O3 grade of 9.86%, and yield of 12.80%.

[0039] Example 2

[0040] Compared with Example 1, the difference of this embodiment is that the diameter of the sieve hole of the high-frequency vibration fine screen is set to 0.3 mm, the particle size control result of the desludging equipment is +0.05 mm material and -0.05 mm material, the quartz selection process is streamlined to four times, and the comprehensive recycling of weathered complex kaolin is achieved.

[0041] The main indicators of kaolin products are: Al2O3 grade of 40.32%, SiO2 grade of 53.46%, Fe2O3 grade of 1.42%, and yield of 41.22%. The main indicators of quartz products are: Al2O3 grade of 1.34%, SiO2 grade of 99.92%, Fe2O3 grade of 0.06%, and yield of 14.55%. The yield of mica products is 4.76%. The main indicators of feldspar products are: K2O grade of 18.37%, Al2O3 grade of 8.11%, SiO2 grade of 72.44%, Fe2O3 grade of 0.15%, and yield of 28.41%. The main indicators of aerated brick raw materials are: Al2O3 grade of 10.22%, SiO2 grade of 68.55%, Fe2O3 grade of 8.46%, and yield of 11.06%.

[0042] This embodiment controls the mesh size during multi-gradient grading, enabling comprehensive recycling of weathered, complex kaolin. The different results are primarily reflected in the purity and yield of various products. For quartz products, large mesh sizes result in lower yields, but the purity is raised to a high standard, the process is shortened, and reagent usage is reduced. Other product indicators also change accordingly, and specific adjustments can be made based on market prices and social demand.

[0043] Example 3

[0044] The weathered complex kaolin sample used in this example was obtained from a certain area in Huidong, Guangdong Province. The surface minerals were taken after complete weathering, and the samples were subjected to particle size classification. The products of each particle size were detected by XRD, and the contents of quartz, feldspar, mica, and kaolin were roughly analyzed. The main results are shown in Table 2.

[0045] Table 2 Analysis of particle size of weathered complex kaolin

[0046]

[0047] A full element analysis was performed on the weathered complex kaolin sample used in this example, and the results showed that the main elements were silicon, potassium, aluminum, and iron, with contents of 25.46%, 10.32%, 9.1%, and 2.78%, respectively. At the same time, according to its XRD results, the main minerals in the weathered complex kaolin were quartz, feldspar, kaolin, and mica, with contents of 35%, 25%, 20%, and 5%, respectively.

[0048] The process flow and reagent system of Example 1 are adopted to comprehensively recycle the weathered kaolin, wherein the main indicators of the kaolin product are: Al2O3 grade is 42.26%, SiO2 grade is 48.24%, Fe2O3 grade is 0.92%, and the yield reaches 37.55%; the main indicators of the quartz product are: Al2O3 grade is 1.34%, SiO2 grade is 97.88%, Fe2O3 grade is 0.21%, and the yield reaches 16.32%; the yield of the mica product reaches 5.75%; the main indicators of the feldspar product are: K2O grade is 27.27%, Al2O3 grade is 12.63%, SiO2 grade is 76.44%, Fe2O3 grade is 0.19%, and the yield reaches 27.32%. The main indicators of aerated brick raw material products are: Al2O3 grade is 9.05%, SiO2 grade is 65.55%, Fe2O3 grade is 10.86%, and the yield reaches 13.06%.

[0049] The embodiments described above are only preferred specific implementation methods of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the technical scope of the present invention, and they should be covered by the scope of protection of the present invention.

Claims

1. A method for comprehensive utilization of weathered complex kaolin, comprising the following steps: 1) adding weathered complex kaolin to water to form a slurry, then adding a dispersant to the slurry, and then stirring and scrubbing to obtain a scrubbed slurry; 2) coarsely screening the slurry after scrubbing in step 1) to remove non-mineral impurities in the weathered complex kaolin, and then screening it using a high-frequency vibration fine screen to obtain an oversize material and an undersize material; 3) Desliming the undersize material in step 2), controlling the sieve aperture diameter of the desliming equipment, and obtaining a coarse-grained oversize material and a fine-grained undersize material; 4) subjecting the fine-grained undersize material obtained in step 3) to high-intensity magnetic separation to obtain non-magnetic minerals and magnetic products, wherein the non-magnetic minerals are kaolin products, and the magnetic products are used as raw materials for aerated bricks; 5) The coarse-grained oversize material obtained in step 3) is subjected to one roughing and one or more flotation cleaning, and the final concentrate obtained is a mica product; the tailings obtained from the roughing are mixed with the middlings obtained from the cleaning, and are recorded as middlings 1; 6) ball milling the oversize material obtained in step 2), and then desludging, controlling the sieve hole diameter of the desludging equipment to obtain a non-sludge portion and a sludge portion; the sieve hole diameter of the desludge equipment is consistent with the sieve hole diameter of the desludge equipment in step 3); the sludge portion is recorded as middling ore 2; 7) The non-mud portion in step 6) is subjected to flotation with one roughing and six or more scavenging steps to obtain a quartz product; the froth products of the roughing and scavenging steps are mixed and recorded as middling ore 3; 8) The middling ore 1 from step 5), the middling ore 2 from step 6), and the middling ore 3 from step 7) are mixed, a defoamer and a dispersant are added, and the mixture is stirred uniformly. The mixture is then subjected to high-intensity magnetic separation to remove impurities, thereby obtaining a magnetic portion and a non-magnetic portion. The non-magnetic portion is subjected to multi-stage reverse flotation to remove impurities, ultimately obtaining a feldspar product and a reverse flotation foam product. The magnetic product and the reverse flotation foam product are mixed to serve as a raw material for aerated bricks.

2. The method according to claim 1, characterized in that In step 1), the concentration of the ore pulp is 25% to 40%; the dispersant is water glass, and the amount is 300g / t; the stirring and scrubbing is performed at a stirring speed of 1200 to 2000r / min and a stirring time of 7 to 10min.

3. The method according to claim 1, characterized in that In step 2), the mesh diameter of the coarse screening sieve is 2-4 cm; the mesh diameter of the high-frequency vibration fine sieve is 0.15-0.3 mm.

4. The method according to claim 1, wherein In step 3), the sieve hole diameter of the desludging equipment is controlled to be 0.03 mm to 0.05 mm.

5. The method according to claim 1, wherein In step 4), the high-intensity magnetic separation is at least one rough magnetic separation and one or more fine magnetic separations, and the magnetic field intensity is controlled to be above 1.5T.

6. The method according to claim 1, characterized in that In step 5), the pH of the flotation is 2-3, sodium hexametaphosphate and sodium fluorosilicate are used as combined inhibitors, and dodecylamine is used as a collector.

7. The method according to claim 1, characterized in that In step 6), the ball mill controls the grinding fineness to be 60% to 80% of the particle size of -0.074 mm.

8. The method according to claim 1, characterized in that In step 7), the flotation is carried out by adjusting the pH of the pulp to 2-3 using hydrochloric acid + oxalic acid as adjusting agents, using water glass as an inhibitor, cetyltrimethylammonium chloride as a collector, and pine oil as a foaming agent.

9. The method according to claim 1, characterized in that In step 8), the stirring speed is 1200-2000 r / min, and the stirring time is 7-10 min.

10. The method according to claim 1, characterized in that In step 8), the high-intensity magnetic separation is at least one roughing magnetic separation and one or more magnetic separations, and the magnetic field intensity is controlled at above 1.5 T; the multi-stage reverse flotation is one roughing separation and three or more scavenging separations, and sodium carbonate is used as an adjusting agent to adjust the pulp pH to 8-9, potassium chloride and citric acid are combined in a mass ratio of (3-1): (0.6-0.3) as an inhibitor, and sodium oleate, benzohydroxamic acid and coconut amine are compounded in a mass ratio of (5-3): (3-1): (0.1-0.05) as a combined collector.

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