A comprehensive utilization method for low-grade, off-balance sheet urban mineral resources

Abstract

This application relates to the field of mineral processing, and more particularly to a method for the comprehensive utilization of low-grade, off-balance sheet urban mineral resources. The method comprises the following steps: obtaining clay minerals and classifying them using a hydraulic classifier to obtain overflow ore and underflow ore; grinding, plasticizing, mixing, and sintering the underflow ore to make bricks; screening and casting the overflow ore to obtain near-end ore (with a short drop distance) and far-end ore (with a long drop distance); and breaking up, grinding, and calcining the near-end ore, followed by mixing with water glass, phosphorus slag, aluminum silicate, and gypsum to form geopolymer. The process of the present invention is simple and easy to operate, achieving the processing and utilization of low-grade minerals with low cost, readily available raw materials, and no tailings pollution.

Description

Technical Field

[0001] The present application relates to the field of mineral processing, and in particular to a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources. Background Art

[0002] Mineral resources are scarce, valuable, and non-renewable. Further development and research of mineral resources, along with the implementation of efficient utilization and sustainable development, are of vital economic and social significance. However, the current technology for the efficient and comprehensive utilization of off-balance sheet and low-grade ores lags behind, resulting in low levels of development and utilization, and insufficient intensive utilization. For example, the various weathering residual and sedimentary clay minerals widely distributed in the Southern Fujian Triangle region, through particle size analysis, X-ray powder diffraction, and infrared spectroscopy, have shown that most are kaolinite-type silty clays composed primarily of kaolinite and quartz. These clays have a quartz content greater than 20%, an alumina content less than 30%, and a poor whiteness. Due to their low grade, multiple components, and difficulty in selection, they remain largely unmined and poorly utilized. Summary of the Invention

[0003] In order to address the deficiencies of the prior art, the present application provides a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources.

[0004] This application provides a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources, which adopts the following technical solutions:

[0005] A method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources comprises the following steps:

[0006] (1) Obtain clay minerals and classify them through a hydraulic classifier to obtain overflow ore and underflow ore;

[0007] (2) Grind and plasticize the underflow ore, then mix it with part of the overflow ore, calcium carbonate, and talc, add appropriate amount of water and press it into a blank. After drying the blank, put it into a kiln and sinter it into bricks;

[0008] (3) Screening the overflow ore to obtain oversize ore and undersize ore, and merging the oversize ore with the underflow ore;

[0009] (4) The ore under the screen is dried and then cast to obtain near-end ore with a short casting distance and far-end ore with a long casting distance; after the above process, the particle size distribution of kaolin and quartz sand has become relatively concentrated, with a high degree of overlap, and it is difficult to separate them by ordinary methods. When the particle size and volume are similar, the materials are cast to make a certain degree of separation of materials of different qualities, and the far-end ore with a higher concentration of kaolin is obtained to meet the material requirements of the all-white clay catalyst.

[0010] (5) The proximal ore is broken up, ground, calcined, and then mixed with water glass, phosphorus slag, aluminum silicate, and gypsum to form geopolymer.

[0011] Preferably, the grinding particle size in step (2) is D85<10mm.

[0012] By adopting the above technical solution, the underflow ore can be fully dispersed in the subsequent plasticizing and mixing stages, the modification effect is better, the sintered product has a more uniform texture and higher strength.

[0013] Preferably, the bottom flow ore is plasticized in step (2) by adding polymaleic acid for blending and plasticizing.

[0014] By adopting the above technical solution, the plasticizing capacity of the underflow ore can be enhanced to meet the material requirements of building bricks, improve the molding effect of the bricks and the sintering strength of the products.

[0015] Preferably, the step (2) comprises the following components in parts by weight: 70-80 parts of underflow ore, 10-20 parts of overflow ore, 5-10 parts of calcium carbonate, and 2-5 parts of talc.

[0016] By adopting the above technical solution, the prepared brick products have better performance, higher strength and stronger fracture resistance.

[0017] Preferably, the sieving in step (3) uses a 20-30 micron vibrating screen.

[0018] By adopting the above technical solution, the material with the largest quartz content and a particle size of more than 20 microns is dried out, which can further reduce the quartz content in the material.

[0019] Preferably, the step (5) comprises the following components in parts by weight: 50-70 parts of proximal ore, 5-10 parts of water glass, 20-30 parts of phosphorus slag, 3-5 parts of aluminum silicate, and 1-3 parts of gypsum.

[0020] By adopting the above technical solutions, the strength, gel time, crack resistance and corrosion resistance of the geopolymer are optimized, and the product performance is optimal.

[0021] Preferably, the grinding particle size in step (5) is D90<15mm.

[0022] By adopting the above technical solution, the proximal ore can be fully dispersed in the subsequent mixing stage, and the product after sintering has a more uniform texture and higher strength.

[0023] Preferably, the method includes step (6) of adding water to the remote ore to make a slurry, wet grinding the ore, spray drying the ore into microspheres, adding an additive to the microspheres, calcining, crystallizing, and post-treating the microspheres to prepare a full clay catalyst.

[0024] Preferably, the auxiliary agent in step (6) is aluminum chloride or aluminum chloride vapor.

[0025] By adopting the above technical solution, aluminum chloride can accelerate the hydroxyl group separation rate during the calcination process, adjust the silicon-aluminum ratio of the product, and improve the performance of the product.

[0026] Preferably, the aluminum chloride or aluminum chloride vapor is added at a temperature of 250-350°C.

[0027] By adopting the above technical solution, the intervention activity of aluminum chloride at this stage is stronger, which can better affect the calcination process.

[0028] By adopting the above technical solution, the separation and utilization of low-grade clay minerals are realized, and building bricks, geopolymers and all-clay FCC catalysts with higher added value are prepared.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. The present invention uses low-grade clay minerals as raw materials and selects them through hydraulic classification equipment to obtain underflow ore and overflow ore enriched with quartz and kaolin, respectively; the underflow ore is used to prepare building bricks, and the overflow ore is further screened to obtain undersize ore with secondary enrichment of kaolin. After the undersize ore is dried and cast, the distal ore with tertiary enrichment of kaolin is used to prepare a full-clay FCC catalyst, and the proximal ore is used to prepare geopolymer, thereby maximizing the comprehensive utilization of clay minerals.

[0031] 2. The process of the present invention is simple and easy to operate. It realizes the processing and utilization of minerals without flotation. It has the characteristics of low cost, easy availability of raw materials, and no tailings pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0033] In order to better understand the present invention, the following examples are provided to further illustrate the present invention, but the protection content of the present invention is not limited to the following examples. In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention.

[0034] As used herein, the term "prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0035] The clay mineral compositions and contents in the following examples are roughly as follows (%):

[0036] SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O crystal water 74.31 17.38 0.87 0.35 0.13 0.98 0.08 0.42

[0037] Example 1

[0038] like Figure 1 As shown, the present invention provides a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources, comprising the following steps:

[0039] (1) Obtain clay minerals and classify them through a hydraulic classifier to obtain overflow ore and underflow ore;

[0040] (2) Grind the underflow ore to a particle size of D85 < 10 mm, then add 3-7% of the underflow ore by weight of polymaleic acid to blend and plasticize. After plasticization, mix it with overflow ore, calcium carbonate, and talc according to the formula ratio, add appropriate amount of water and press it into a blank. After drying, place the blank in a kiln and sinter it at 900℃ to form bricks. The formula is as follows: 70 parts of underflow ore, 10 parts of overflow ore, 5 parts of calcium carbonate, and 2 parts of talc.

[0041] (3) The overflow ore is screened using a 20-30 micron vibrating screen to obtain oversize ore and undersize ore, and the oversize ore is combined with the underflow ore;

[0042] (4) Drying the undersize ore and then throwing it to obtain near-end ore with a short throwing distance and far-end ore with a long throwing distance;

[0043] (5) The proximal ore is broken up and ground to a particle size of D90 < 15 mm. After calcination, it is mixed with water glass, phosphorus slag, aluminum silicate, and gypsum according to the formula ratio to form a geopolymer. The formula is as follows: 50 parts of proximal ore, 5 parts of water glass, 20 parts of phosphorus slag, 3 parts of aluminum silicate, and 1 part of gypsum. The phosphorus slag is electric furnace phosphorus slag with a CaO content of > 45% and a P content of < 1.5%.

[0044] (6) The remote ore is slurried with water and then wet-ground, and then spray-dried into microspheres. The microspheres are then added with aluminum chloride or aluminum chloride vapor for roasting, crystallization, and post-treatment to produce a fully clay-type catalyst. The addition temperature of aluminum chloride or aluminum chloride vapor is 250°C. Specifically, the remote ore is added with water to produce a slurry with a solid content of 40%, and sodium silicate is added and spray-dried into microspheres. The microspheres are roasted in a kiln at 900°C for 3-4 hours with aluminum chloride to obtain a calcined material, which is then mixed with sodium silicate, alkali solution, zeolite, and deionized water under stirring and crystallized at a constant temperature of 90°C. After crystallization, the microspheres are filtered, washed, and dried to obtain a microsphere crystallized catalyst.

[0045] Example 2

[0046] like Figure 1 As shown, the present invention provides a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources, comprising the following steps:

[0047] (1) Obtain clay minerals and classify them through a hydraulic classifier to obtain overflow ore and underflow ore;

[0048] (2) Grind the underflow ore to a particle size of D85 < 10 mm, then add 3-7% of polymaleic acid to the underflow ore as a plasticizer. Mix it with overflow ore, calcium carbonate, and talc according to the formula ratio. Add appropriate amount of water to press it into a blank. After drying the blank, place it in a kiln and sinter it at 1000℃ to form bricks. The formula is as follows: 75 parts of underflow ore, 15 parts of overflow ore, 7 parts of calcium carbonate, and 4 parts of talc.

[0049] (3) The overflow ore is screened using a 20-30 micron vibrating screen to obtain oversize ore and undersize ore, and the oversize ore is combined with the underflow ore;

[0050] (4) Drying the undersize ore and then throwing it to obtain near-end ore with a short throwing distance and far-end ore with a long throwing distance;

[0051] (5) The proximal ore is broken up and ground to a particle size of D90 < 15 mm. After calcination, it is mixed with water glass, phosphorus slag, aluminum silicate, and gypsum according to the formula ratio to form a geopolymer. The formula is as follows: 60 parts of proximal ore, 7 parts of water glass, 25 parts of phosphorus slag, 4 parts of aluminum silicate, and 2 parts of gypsum. The phosphorus slag is electric furnace phosphorus slag with a CaO content of > 45% and a P content of < 1.5%.

[0052] (6) The remote ore is slurried with water and then wet-ground, and then spray-dried into microspheres. The microspheres are then added with aluminum chloride or aluminum chloride vapor for roasting, crystallization, and post-treatment to produce a fully clay-type catalyst. The addition temperature of aluminum chloride or aluminum chloride vapor is 250°C. Specifically, the remote ore is added with water to produce a slurry with a solid content of 40%, and sodium silicate is added and spray-dried into microspheres. The microspheres are roasted in a kiln at 900°C for 3-4 hours with aluminum chloride vapor to obtain a calcined material, which is then mixed with sodium silicate, alkali solution, zeolite, and deionized water under stirring and crystallized at a constant temperature of 90°C. After crystallization, the catalyst is filtered, washed, and dried to obtain a microsphere crystallized catalyst.

[0053] Example 3

[0054] like Figure 1 As shown, the present invention provides a method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources, comprising the following steps:

[0055] (1) Obtain clay minerals and classify them through a hydraulic classifier to obtain overflow ore and underflow ore;

[0056] (2) Grind the underflow ore to a particle size of D85 < 10 mm, then add 3-7% of polymaleic acid by weight of the underflow ore to blend and plasticize it. Mix it with overflow ore, calcium carbonate, and talc according to the formula ratio. Add appropriate amount of water to press it into a blank. After drying the blank, place it in a kiln and sinter it at 1100℃ to form bricks. The formula is as follows: 80 parts of underflow ore, 20 parts of overflow ore, 10 parts of calcium carbonate, and 5 parts of talc.

[0057] (3) The overflow ore is screened using a 20-30 micron vibrating screen to obtain oversize ore and undersize ore, and the oversize ore is combined with the underflow ore;

[0058] (4) Drying the undersize ore and then throwing it to obtain near-end ore with a short throwing distance and far-end ore with a long throwing distance;

[0059] (5) The proximal ore is broken up and ground to a particle size of D90 < 15 mm. After calcination, it is mixed with water glass, phosphorus slag, aluminum silicate, and gypsum according to the formula ratio to form a geopolymer. The formula is as follows: 70 parts of proximal ore, 10 parts of water glass, 30 parts of phosphorus slag, 5 parts of aluminum silicate, and 3 parts of gypsum. The phosphorus slag is electric furnace phosphorus slag with a CaO content of > 45% and a P content of < 1.5%.

[0060] (6) The remote ore is slurried with water and then wet-ground, and then spray-dried into microspheres. The microspheres are then added with aluminum chloride or aluminum chloride vapor for roasting, crystallization, and post-treatment to produce a fully clay-type catalyst. The addition temperature of aluminum chloride or aluminum chloride vapor is 300°C. Specifically, the remote ore is added with water to produce a slurry with a solid content of 40%, and sodium silicate is added and spray-dried into microspheres. The microspheres are taken and roasted in a kiln at 900°C for 3-4 hours with aluminum chloride to obtain a calcined material. The calcined material is then mixed with sodium silicate, alkali solution, zeolite, and deionized water under stirring and crystallized at a constant temperature of 90°C. After crystallization, the material is filtered, washed, and dried to obtain a microsphere crystallized catalyst.

[0061] Comparative Example 1

[0062] Clay mineral is ground to a particle size of D85 <10mm, then polymaleic acid is added for blending and plasticization. After plasticization, it is mixed with calcium carbonate and talc according to the formula ratio. An appropriate amount of water is added to press the green body into a green body. After drying, the green body is placed in a kiln and sintered at 900°C to form a brick. The formula is as follows: 70 parts clay mineral, 5 parts calcium carbonate, and 2 parts talc.

[0063] Comparative Example 2

[0064] Clay mineral is obtained, and a portion is graded in a hydraulic classifier to obtain overflow ore and underflow ore. The remaining portion is ground to a particle size of D85 <10mm. Polymaleic acid is then added to blend and plasticize the mixture. After plasticization, the mixture is mixed with overflow ore, calcium carbonate, and talc according to the formula ratio. An appropriate amount of water is added to press the mixture into a blank. After drying, the blank is placed in a kiln and sintered at 900°C to form a brick. The formula is as follows: 70 parts clay mineral, 10 parts overflow ore, 5 parts calcium carbonate, and 2 parts talc.

[0065] Comparative Example 3

[0066] The only difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, the formula in step (2) is the components in parts by weight, 70 parts of underflow ore, 0 parts of overflow ore, 5 parts of calcium carbonate, and 2 parts of talc, and the rest are the same as in Example 1.

[0067] Comparative Example 4

[0068] The only difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, step (2) is to grind the underflow ore, then mix it with part of the overflow ore, calcium carbonate, and talc, add an appropriate amount of water to press it into a blank, dry the blank, and then put it into a kiln to sinter it into bricks. The rest is the same as Example 1.

[0069] Comparative Example 5

[0070] The overflow ore from Example 1 was crushed, ground to a particle size of D90 <15 mm, and calcined. The mixture was then mixed with water glass, phosphorus slag, aluminum silicate, and gypsum according to the formula ratio to form a geopolymer. The formula, by weight, was 50 parts overflow ore, 5 parts water glass, 20 parts phosphorus slag, 3 parts aluminum silicate, and 1 part gypsum. The phosphorus slag used was electric furnace phosphorus slag with a CaO content of >45% and a phosphorus content of <1.5%.

[0071] Comparative Example 6

[0072] The only difference between Comparative Example 6 and Example 1 is that in Comparative Example 6, step (6) is to add water to the remote ore to make a slurry and then wet grind the ore, and then spray dry it into microspheres, and the microspheres are calcined, crystallized, and post-treated to prepare a full-clay catalyst. The rest is the same as Example 1.

[0073] Results: The parameters of the products obtained in Examples 1-3 and Comparative Examples 1-6 were tested, and the specific data are shown in the following table:

[0074] Table 1 Performance test of building bricks prepared in Example

[0075] project Apparent porosity Bulk density Compressive strength Wear unit g / cm3 Mpa Example 1 ＜20 ＞2 ＞6 ＜10% Example 2 ＜20 ＞2 ＞6 ＜8% Example 3 ＜20 ＞2 ＞6 ＜8% Comparative Example 1 ＞35 ＜1.3 ＜3 ＞25% Comparative Example 2 ＞25 ＜1.5 ＜5 ＞15% Comparative Example 3 ＞20 ＜1.5 ＜5 ＞15% Comparative Example 4 ＜20 ＜2 ＜5 ＞12%

[0076] In Table 1, the test sample size is 300x300mm, and the wear rate is the weight loss ratio of the sample brick after the roller brush sweeps the sample brick surface for 24 hours. The roller brush is at 120r / min, and the sample brick is suspended above the roller brush.

[0077] Table 2 Performance test of geopolymer prepared in Example

[0078] project Setting time Compressive strength Anti-permeability Corrosion resistance coefficient unit h Mpa Example 1 ＜6 ＞12 good ＞0.9 Example 2 ＜6 ＞12 good ＞0.9 Example 3 ＜6 ＞12 good ＞0.9 Comparative Example 5 ＜6 ＜8 generally ＞0.9

[0079] Table 3 Performance test of all-clay catalyst prepared in Example

[0080] sample Micro-Activity Example 1 ＞50% Example 2 ＞50% Example 3 ＞50% Comparative Example 6 ＜45%

[0081] Table 3 Catalyst micro-reaction activity was determined using NB / SH / T 0952-2017.

[0082] In summary, the building bricks, geopolymers, and catalysts prepared by the comprehensive utilization method of low-grade, off-balance sheet urban mineral resources of the present invention all meet the minimum industrial use indicators. Without using heavily polluting mineral processing methods such as flotation and pickling, low-grade clay minerals can be utilized in a more economical way, producing industrial products with higher added value.

[0083] It should be understood that the specific embodiments described above are only used to explain the present invention and are not intended to limit the present invention. Obvious changes or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for comprehensive utilization of low-grade, off-balance sheet urban mineral resources, characterized in that The following steps are involved: (1) Obtain clay minerals and classify them through a hydraulic classifier to obtain overflow ore and underflow ore; (2) Grind the underflow ore to a particle size of D85 < 10 mm, then add 3-7% of the mass ratio of the underflow ore to the polymaleic acid blending and plasticizing, mix it with the overflow ore, calcium carbonate, and talc according to the formula ratio, add appropriate amount of water to press it into a blank, dry the blank, put it into a kiln and sinter it at 1000 ° C to form a brick; the formula is the number of components in parts by weight, 75 parts of underflow ore, 15 parts of overflow ore, 7 parts of calcium carbonate, and 4 parts of talc; (3) The overflow ore is screened using a 20-30 micron vibrating screen to obtain oversize ore and undersize ore, and the oversize ore is combined with the underflow ore; (4) Drying the undersize ore and then throwing it to obtain near-end ore with a short throwing distance and far-end ore with a long throwing distance; (5) The proximal ore is broken up and ground to a particle size of D90 < 15 mm, calcined, and then mixed with water glass, phosphorus slag, aluminum silicate, and gypsum according to a formula ratio to form a geopolymer; the formula is composed of 60 parts of proximal ore, 7 parts of water glass, 25 parts of phosphorus slag, 4 parts of aluminum silicate, and 2 parts of gypsum by weight; the phosphorus slag is electric furnace phosphorus slag with a CaO content of > 45% and a P content of < 1.5%; (6) Add water to the remote ore to prepare a slurry with a solid content of 40%, then wet grind the ore, and add sodium silicate to spray dry it into microspheres; take the microspheres and add aluminum chloride vapor in a kiln to roast at 900°C for 3-4 hours to obtain a calcined material, which is mixed with sodium silicate, alkali solution, zeolite and deionized water under stirring and crystallized at a constant temperature of 90°C; after crystallization, filter, wash and dry to obtain a full-clay microsphere crystallization catalyst.

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