A method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz

Abstract

The present invention discloses a method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz, including: coordinating and scrubbing the raw ore with a dispersant; removing 400 mesh fine mud by sedimentation to extract silicon and reduce impurities; removing iron-containing minerals by strong magnetic separation to obtain magnetic and non-magnetic materials; screening the non-magnetic materials to remove +40 mesh coarse particles; using a new agent to reversely flotate the 40+400 mesh non-magnetic materials to remove feldspar and other black impurity minerals to obtain a flotation concentrate; screening the flotation concentrate to obtain 40+80 mesh coarse particles, which are then pickled, calcined, water-quenched, and pickled to obtain a 4N grade high-purity quartz concentrate; screening the flotation concentrate to obtain 80+400 mesh fine particles, which are then pickled once to obtain a 3N7 grade high-purity quartz concentrate; the fine mud, magnetic materials, +40 mesh coarse particles, and flotation quartz can be used to make aerated bricks and new building materials. The present invention realizes the cascade high-value utilization of Cambrian powder quartz resources, greatly improves economic value and social benefits, and is also applicable to the purification of other types of powder quartz.

Description

Technical Field

[0001] The invention belongs to the technical field of deep processing of non-metallic minerals, and in particular relates to a method for purifying Cambrian powdered quartz to prepare 4N grade high-purity quartz. Background Art

[0002] With the rapid advancement of science and technology, high-purity quartz has become an irreplaceable key material in high-tech fields such as semiconductors, photovoltaics, and new energy. Pink quartz is a natural quartz mineral resource formed through natural weathering, leaching, and fragmentation, with a soil-like appearance. It is naturally produced in a powdery form with a loose structure that crushes easily into powder when dry. Contaminated by iron, mud, and other minerals, it exhibits a red or yellowish-brown color. Purification can yield high-purity quartz concentrate. Pink quartz has a naturally fine particle size, a relatively regular shape, and an aspect ratio close to 1:1, making it considered a high-quality industrial silicon raw material. However, traditional bulk quartz resources tend to form needle-shaped particles after crushing and grinding. These needle-shaped particles can easily clog feed channels during quartz glass production. Furthermore, processing bulk quartz requires a crushing and grinding process, which is costly. Therefore, research on the high-value purification of pink quartz is of great significance.

[0003] The difficulty in purifying pink quartz is mainly due to the fact that pink quartz ore is a weathered fine-grained ore. Weathering forms inert impurities or impregnation impurities on the surface of pink quartz particles or between cracks that are extremely difficult to remove. At the same time, during the mineralization or mining process, clay impurities of co-existing silicate minerals with extremely fine particle size and physical and chemical properties that are extremely similar to those of pink quartz particles are mixed in, as well as a small amount of inclusion impurities and lattice impurities. Inclusion impurities are mostly present in the form of less than 10μm inside the quartz particles. Different impurity types and contents seriously affect the performance of downstream quartz products, making the purification of pink quartz much more difficult than that of hard rock quartz ore. Although the quality of pink quartz ore is poor and the particle size is fine, with the advancement of purification technology, pink quartz can still enter the high-end quartz products industry.

[0004] In recent years, my country has discovered large-scale, high-quality pink quartz resources in Guangxi, Jiangxi, Guizhou, and other regions. Jiangxi's pink quartz ore boasts a SiO2 content of 99% and a high whiteness. Its reserves and annual production rank first in China, attracting considerable research interest. High-purity quartz generally requires a SiO2 content greater than 99.9% and an Fe2O3 content less than 10μg / g (Fe content less than 7μg / g). Due to its fine particle size, pink quartz can eliminate the need for crushing and grinding, significantly reducing purification costs. Therefore, purifying 4N-grade high-purity quartz from abundant pink quartz reserves could address the current situation of poorly utilized high-quality resources and maximize the value of pink quartz. Currently, pink quartz purification technologies are primarily divided into physical and chemical methods. Physical methods, which primarily aim to remove most clay impurities and associated mineral impurities, include scrubbing and desludging, gravity classification, magnetic separation, and flotation. Chemical methods, on the other hand, include roasting, acid leaching, and chlorination.

[0005] Tang Chunhua et al. (Patent No. CN202311552681.8) have published a process for purifying natural powdered quartz into 4N-grade high-purity fine-grained quartz sand. Using Jiangxi powdered quartz (ore with a SiO2 content of 99.08%, Al2O3 content of 0.49%, and Fe2O3 content of 0.075%), they employed a combination of physical and chemical purification methods, including screening, magnetic separation, flotation, calcination, and acid leaching, to ultimately produce a high-purity quartz concentrate with a SiO2 content of 99.992%. The powdered quartz used in this invention is of high quality and whiteness. The raw ore SiO2 content has reached 99%, and the iron and aluminum contents are very low, laying a good foundation for the purification and preparation of high-purity quartz concentrate.

[0006] Wu Zhaoyang et al. selected powder quartz ore from a certain place in Jiangxi as raw material (Research on Mineral Processing and Purification Technology of Powder Quartz in Jiangxi, China Non-metallic Mineral Industry Guide, Issue 4, 2011). 97.90%, Al2O3 content The content of SiO2 is 1.15%, and the content of TFe is 0.024%. Through scrubbing, graded desliming, magnetic separation, flotation, pickling, calcination and other treatment processes, the SiO2 content is ≥99.93%, and the content of impurities such as iron and aluminum is low. The product is silicon micropowder that meets the requirements of the electronics and electrical industry. The purification process uses calcination and pickling, and the purity of quartz only reaches 3N. There is still room for further improvement.

[0007] Du Jie et al. (patent number CN201910724769.0) announced a method for the beneficiation and purification of incompletely weathered powder quartz. Using Guangxi powder quartz (the original ore has an SiO2 content of 94.32%, an Al2O3 content of 2.15%, and an Fe2O3 content of 0.043%), they adopted physical purification methods such as scrubbing-screening-selective flocculation-reverse flotation, and finally obtained a quartz concentrate with an SiO2 content of only 99.2%. The purity of the quartz is relatively low and there is room for further improvement.

[0008] Luo Shaodong et al. took five kinds of powder quartz ores produced in Qiannan Prefecture as the research objects (Research on the Characteristics and Processing Technology of Powder Quartz in Qiannan Prefecture, Guizhou, "Mineral Protection and Utilization" Issue 2, 2013). The SiO2 content of the original ore was 95.3%~98%; it was purified by water washing and acid leaching. After acid washing and purification, the SiO2 content was above 99.30%. Although chemical purification was used, the final SiO2 purity only reached 2N. The added value of quartz concentrate products was low and needs to be further improved.

[0009] From the above, we can see that the current research results on the purification of pink quartz are mainly focused on the preparation of pink quartz with SiO2 content of 99% and 99.9%, and there is still a lack of effective sorting methods for the preparation of 99.99% high-purity quartz.

[0010] Recently, a large, previously unreported deposit of pink quartz was discovered in the Cambrian system of southern Tongren, Guizhou. This deposit is a typical weathering-infused type, characterized by loose accumulation. Under the combined influence of wind, tides, and coastal currents, the clastic material is repeatedly washed and accumulated, forming quartz sand layers. Due to the presence of mud, the quartz sand is red in color. The raw pink quartz ore in Guizhou has a SiO2 content of 65.48% to 95.10%, an average grade of 82.95%, an Al2O3 content of 1.4% to 15.64%, and a Fe2O3 content of 0.56% to 7.06%. The rock composition is primarily composed of quartz, siliceous debris, clay minerals, and iron oxides. The ore structure is primarily anisotropic sandy and micro-fine-grained, with fragmented and massive structures being the predominant structures. The SiO2 content of the selected samples of Jiangxi pink quartz is about 99%, the Al2O3 content is about 0.5%, and the Fe2O3 content is less than 0.1% (patent CN202311552681.8). Obviously, Guizhou pink quartz and Jiangxi pink quartz are different in type and quality. Guizhou pink quartz is red, while Jiangxi pink quartz is white. The silicon content of Jiangxi pink quartz ore is much higher than that of Guizhou. It is extremely difficult to purify Guizhou Cambrian pink quartz to prepare 4N grade high-purity quartz. There is currently no relevant literature or patent reporting the successful preparation of 4N grade high-purity quartz. Therefore, the 4N grade purification technology for this Cambrian pink quartz is still blank.

[0011] In view of this, the present invention is proposed. Summary of the Invention

[0012] In order to change the current situation of poor utilization of high-quality Cambrian pink quartz resources, the present invention provides a method for purifying and preparing 4N grade high-purity quartz by using pink quartz ore in a coordinated dispersant-coupled scrubbing-sedimentation desliming-magnetic separation-screening-flotation-classification-pickling-calcination water quenching-pickling. The method introduces a dispersant-coupled scrubbing to fully cleave and disperse the pink quartz and fine clay particles, remove clay minerals and impregnated iron minerals to a greater extent, achieve efficient separation of concentrate and clay slurry, effectively improve silicon quality and reduce iron and aluminum impurities, and then use a collector with good selectivity and excellent synergy to remove feldspar and other black impurity minerals in the pink quartz, achieve deep separation of the pink quartz and various impurities, and lay a foundation for the subsequent calcination and acid leaching chemical purification to prepare high-purity quartz. The present invention can greatly improve the application range and economic benefits of Cambrian pink quartz ore.

[0013] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0014] A method for purifying Cambrian powdered quartz to prepare 4N grade high-purity quartz comprises the following steps:

[0015] Step 1: Coordinated scrubbing of raw ore with dispersant: Cambrian pink quartz is used as the raw ore to be selected, dispersant and water are added, and scrubbed and stirred in a scrubbing machine to obtain scrubbing slurry;

[0016] Step 2, sedimentation and desliming: Pour the scrub slurry obtained in step 1 into a measuring cylinder, stir it thoroughly and let gravity sedimentation remove the sludge, repeat this desliming process several times until the supernatant is transparent, and obtain quartz coarse sand and sludge;

[0017] Step 3, strong magnetic separation: the quartz coarse sand material obtained in step 2 is subjected to strong magnetic separation to obtain magnetic and non-magnetic materials;

[0018] Step 4, screening: the non-magnetic material obtained in step 3 is screened to remove the +40 mesh coarse particles and increase the silicon content of the -40+400 mesh particle size;

[0019] Step 5, reverse flotation: pour the -40+400 mesh non-magnetic material obtained in step 4 into the flotation machine, adjust the pH of the pulp, add a collector, and perform reverse flotation multiple times to obtain flotation concentrate and middlings;

[0020] Step 6, pickling: the flotation concentrate obtained in step 5 is screened to remove coarse particles of -40+80 mesh, and then pickled and ultrasonically cleaned to obtain acid leaching concentrate;

[0021] Step 7, calcination, water quenching and pickling: calcining, water quenching and pickling the acid leached concentrate obtained in step 6 to obtain 4N grade high-purity quartz concentrate;

[0022] Step 8, pickling: the flotation quartz concentrate obtained in step 5 is screened to obtain -80+400 mesh fine particles and then pickled once to prepare 3N7 grade high-purity quartz concentrate;

[0023] Among them, the ore mud obtained in step 2, the magnetic material obtained in step 3, the +40 mesh coarse particles obtained in step 4, and the flotation ore obtained in step 5 can be made into aerated bricks and new building materials.

[0024] The flotation collector is a mixture of a compound amine, a fatty acid, and a silicate inhibitor; wherein the weight percentage of the compound amine, the fatty acid, and the silicate inhibitor is 7:7:1;

[0025] Screening out the +40 mesh coarse particles can be performed on the coarse sand obtained in step 2 or on the non-magnetic material obtained in step 3.

[0026] The flotation concentrate obtained in step 5 is screened into -40+80 mesh coarse particles and -80+400 mesh fine particles, and can also be screened into other particle sizes such as -40+100 mesh and -100+400 mesh, and high-purity quartz concentrate of different grades and particle sizes can be prepared according to market demand.

[0027] Preferably, in step 1, the dispersant is one of silicates, inorganic strong bases, and long-chain inorganic alkali metal phosphates, or a mixture of two of the two.

[0028] Preferably, in step 2, the sedimentation desliming is performed by extracting once every 5 minutes, for 10-14 times, to remove fine mud below 400 mesh until the slurry is clarified.

[0029] Preferably, in step 3, the strong magnetic separation is wet magnetic separation, and the magnetic separation operation includes a magnetic separation stage with a magnetic field strength of 1.4-2.0T.

[0030] Preferably, in step 4, the sieve is sieved with a 40-mesh standard sieve to separate into +40-mesh coarse particles and -40+400-mesh fine particles. The +40-mesh coarse particles do not meet the particle size requirements of high-purity quartz and have a high impurity content.

[0031] Preferably, in step 5, the reverse flotation is aeration flotation, and the process conditions are: the pulp concentration is 10-30%, the pulp pH is 2-3, the acid for adjusting the pulp is one of sulfuric acid and hydrofluoric acid or a mixture of the two, the amount of collector is 300-600 g / t, the stirring rate is 1200-1500 r / min, the flotation time is 1-2 min, and multiple flotation is performed until all impurities are selected.

[0032] Preferably, in step 6, the flotation quartz concentrate is screened to obtain -40+80 mesh coarse particles for pickling, the mixed acid is a mixture of nitric acid, hydrochloric acid and hydrofluoric acid, the leaching time is 4 to 24 hours, and ultrasonic cleaning is performed.

[0033] Preferably, in step 7, the acid leaching concentrate is calcined in a muffle furnace at 1050° C. for 1 hour, quenched with water, pickled with a mixture of nitric acid, hydrochloric acid, and hydrofluoric acid, the leaching time is 4 to 24 hours, and ultrasonically cleaned to obtain a 4N grade high-purity quartz concentrate.

[0034] Preferably, in step 8, the flotation quartz concentrate is screened to obtain -80+400 mesh fine particles, which are directly subjected to a single acid wash, the leaching time is 4 to 24 hours, and ultrasonic cleaning is performed to obtain a 3N7 grade high-purity quartz concentrate;

[0035] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0036] Combined with XRD analysis, microscopic identification and laser Raman spectroscopy analysis of Guizhou pink quartz, it can be seen that the main sources of iron and aluminum impurities are kaolinite, hematite and feldspar. The pink quartz ore contains liquid-rich inclusions and pure gas-phase inclusions with a size of less than 5μm, and solid inclusions with a size of less than 10μm. The liquid phase component of the liquid-rich inclusions is mainly H2O, and the pure gas-phase inclusion components are mainly C2H4, C3H8, C6H6 and aromatic hydrocarbon gases. The small size of the inclusions and the contamination of long-term weathering clay impurities greatly increase the difficulty of purification. The key to the present invention is the dispersant-coupled scrubbing and dispersion desludging process, which has low processing cost and can remove fine-grained clay minerals and impregnated iron minerals on the surface of fine quartz particles to a greater extent, greatly improving the silicon quality and reducing the content of impurities such as iron and aluminum. After desludging, the quality of fine quartz has a qualitative leap. The SiO2 grade of quartz sand is increased from 92.39% of the original ore to 99.58%, Al2O3 is reduced from 3.41% of the original ore to 0.25%, the aluminum removal rate is 92.6%, Fe2O3 is reduced from 1.66% of the original ore to 0.095%, the iron removal rate is 94.2%, and the quality of fine quartz is greatly improved.

[0037] The present invention further removes feldspar and black impurity minerals in powder quartz through the synergistic effect of new agents, realizes efficient and deep separation of powder quartz and various impurities, greatly improves the purity of flotation quartz concentrate, and lays the foundation for the subsequent calcination and acid leaching purification to prepare high-purity quartz. The new flotation agents are all environmentally friendly agents.

[0038] The present invention eliminates the need for crushing and grinding. Instead, it utilizes the collision and self-friction between raw quartz ore particles. After sufficient cleavage and dispersion with a dispersant, desludging, magnetic separation, screening, flotation, pickling, calcination, water quenching, and pickling, the resulting high-purity quartz concentrate has an SiO2 content of 99.9907%. The byproducts, flotation ore, +40 mesh coarse particles, magnetic materials, and fine mud, can be used as building materials, aerated bricks, cement ingredients, and the like. This invention achieves high-value, cascaded utilization of Cambrian quartz resources, improves the current situation of low-quality use of high-quality resources, improves mine economic benefits, and conforms to the concept of green mining. The present invention has strong applicability and a wide range of applications. It can also provide an economical and efficient purification method for the high-value utilization of other types of quartz.

[0039] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic flow chart of the method of the present invention.

[0041] Figure 2 This is the XRD spectrum of pink quartz ore and ore mud. DETAILED DESCRIPTION

[0042] Example 1

[0043] 150 kg of representative powder quartz samples were collected from the Cambrian powder quartz mine in Guizhou. The samples were air-dried and had a loose appearance with an iron-impregnated red color. No crushing was required. They were gently crushed with a wooden mallet and sieved with a 1 mm sieve. Grass roots and lumps of stone on the sieve were discarded, and the uniform powder below -1 mm was used as the test ore. The results of the multi-element analysis of the ore are shown in Table 1, the XRD analysis results of the ore are shown in Table 2, the XRD analysis results of the 400 mesh fine mud are shown in Table 3, and the XRD spectra of the ore and 400 mesh fine mud are shown in Table 3. Figure 2 .

[0044] Table 1 Ore analysis results (%)

[0045] element <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO content 92.39 3.41 1.66 0.021 element <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[TiO2]]> MgO content 0.16 0.016 0.091 0.069

[0046] The SiO2 content of the pink quartz ore in Table 1 is 92.39%, the Al2O3 content is 3.41%, and the Fe2O3 content is 1.66%. This shows that the high content of clay minerals, iron and other impurities in the Cambrian pink quartz ore in Guizhou affects the quality of the ore, making purification very difficult.

[0047] Table 2 XRD analysis results of raw ore (%)

[0048] Mineral name quartz Kaolinite feldspar hematite content 91.52 5.71 2.75 0.03

[0049] Table 2 shows that the quartz mineral content in the powder quartz ore is 91.52%, the kaolinite mineral content is 5.71%, the feldspar mineral content is 2.75%, and there is a small amount of hematite, indicating that the aluminum-containing minerals are mainly kaolinite and feldspar.

[0050] Table 3 XRD analysis results of 400 mesh fine mud (%)

[0051] Mineral name quartz Kaolinite feldspar hematite content 73.20 23.47 3.14 0.19

[0052] Table 3 The fine mud removed by scrubbing the raw ore has a quartz mineral content of 73.20%, a kaolinite mineral content of 23.47%, a feldspar mineral content of 3.14%, and a hematite content of 0.19%. This indicates that scrubbing removes the paragenetic silicate clay impurities and the impregnation impurities on the surface of quartz particles and between cracks, thereby improving the quality of the quartz concentrate and playing an important role in the subsequent purification and preparation of 4N grade high-purity quartz.

[0053] Combined with attachment Figure 1 The process flow is shown in the figure. 400 g of Cambrian pink quartz ore after mixing is weighed and poured into the scrubber. The XRD spectra of pink quartz ore and ore mud are shown in the figure. Figure 2 , add 400 ml of water and scrub for 30 minutes. One solution is to scrub by collision and self-friction between powdered quartz particles, and the other is to sieve out the +40 mesh coarse particles and add zirconium balls in equal proportion to scrub. Siphon sedimentation desludging tests were carried out respectively, desludging once every 5 minutes, and a total of 14 times were extracted to the scale line 1000. The results of the desludging scheme are shown in Table 4.

[0054] Table 4 Desludging of ore by self-grinding scrubbing and scrubbing with zirconium balls (%)

[0055] Scrubbing and desludging solution product Yield grade Recovery rate <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> Particle self-friction scrubbing mud 30.77 76.66 11.88 5.14 25.64 91.87 90.69 quartz sand 69.23 98.80 0.41 0.21 74.36 8.82 9.31 Zirconium ball scrubbing mud 30.00 77.94 10.81 4.68 25.38 91.18 90.30 quartz sand 70.00 98.24 0.51 0.25 74.62 8.13 9.70

[0056] The quartz sand obtained by using the collision and self-friction between the powdered quartz particles to disperse and remove mud is of better quality than the quartz sand obtained by adding zirconium balls for scrubbing. The removed mud contains more aluminum and iron, and the impurity removal rate is high. Adding zirconium balls will increase the screening process twice. Therefore, using the collision and self-friction between the quartz particles to scrub can save costs and improve the desludging efficiency.

[0057] Weigh 400 g of the mixed Cambrian pink quartz ore and pour it into a scrubber. Add 400 ml of water and add dispersant for coupling scrubbing. Scrub for 30 minutes and pour it into a 2000 ml graduated cylinder for sedimentation and desludging. Desludging is performed once every 5 minutes and extracted 10 times to the scale line 800. The silicon, aluminum and iron in the mud and sand are analyzed to examine the desludging effect of scrubbing under different conditions. The results are shown in Table 5.

[0058] Table 5 Scrubbing and desludging results (%)

[0059] dispersants product Yield grade Recovery rate <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> Dispersant 0 mud 30.77 76.66 11.88 5.14 25.64 91.18 90.30 quartz sand 69.23 98.80 0.51 0.25 74.36 8.82 9.70 Phosphates 300g / t mud 29.25 76.53 12.02 5.30 24.30 92.79 92.18 quartz sand 70.75 98.56 0.39 0.19 75.70 7.21 7.82 Phosphates 600g / t mud 30.00 76.62 11.41 5.23 24.92 94.75 94.35 quartz sand 70.00 98.90 0.27 0.13 75.08 5.25 5.65 Phosphates 800g / t mud 26.33 72.34 14.13 6.16 20.61 95.28 95.86 quartz sand 73.67 99.58 0.25 0.095 79.39 4.72 4.14 Phosphates 1000g / t mud 26.12 72.00 13.82 6.21 20.44 95.69 94.01 quartz sand 73.88 99.10 0.22 0.14 79.56 4.31 5.99 Inorganic strong base 600g / t mud 33.05 78.64 11.27 4.74 28.17 96.45 94.34 quartz sand 66.95 99.01 0.20 0.14 71.83 3.55 5.66 Dispersant return water utilization mud 31.61 77.80 11.18 5.14 26.70 94.86 94.06 quartz sand 68.39 98.70 0.28 0.15 73.30 5.14 5.94

[0060] The desludging effect of phosphate dispersant 800g / t coupled scrubbing is the best, with a mud removal rate of 26.33%, aluminum and iron removal rates both greater than 95%, a quartz sand recovery rate of 73.67%, and quartz sand SiO2 grade increased from 92.39% of the original ore to 99.58%, Al2O3 decreased from 3.41% of the original ore to 0.25%, and Fe2O3 decreased from 1.66% of the original ore to 0.095%. The quality of powder quartz is greatly improved.

[0061] The quartz coarse sand obtained by desliming is added to the wet high-intensity magnetic separator. The magnetic separation operation is a one-stage high-intensity magnetic separation with a magnetic field strength of 1.4~2.0T to obtain non-magnetic and magnetic materials.

[0062] The non-magnetic materials are screened out to remove the +40 mesh coarse particles. This part of the product does not meet the particle size requirements of high-purity quartz and contains high impurities such as iron and aluminum. The purpose is to improve the quality of quartz entering flotation.

[0063] A certain amount of non-magnetic material (-40 + 400 mesh) was weighed and added to the 0.5L flotation cell of an XFD12 flotation machine for reverse flotation of feldspar and other impurity minerals. The flotation pulp concentration was 10-30%, and the pH of the pulp was adjusted to 2-3. After stirring for 1 minute, 300g / t of collector (a mixture of a compound amine, fatty acid, and silicate inhibitor in a weight ratio of 7:7:1) was added. The stirring rate was 1200r / min, the stirring time was 1 minute, and the flotation time was 2 minutes. The froth product consisted of feldspar and impurity minerals, and the product in the cell was the flotation quartz concentrate. To ensure the grade of the flotation quartz concentrate, multiple scavenging operations were performed according to this procedure, and the flotation products were combined to form the final flotation concentrate.

[0064] The flotation quartz concentrate was screened to obtain -40+80 mesh coarse particles, and 20 grams of the sample was weighed and placed in a high-pressure reactor for heated acid leaching test. The mixed acid used was HCl:HNO3:HF=(2~4):1:1, the liquid-solid ratio was 1:2, the leaching temperature was 80℃, and the leaching time was 24 hours. After the acid leaching, the sample was washed with ultrapure water until neutral, and then ultrasonically washed for 10 minutes to further remove impurities on the surface of the quartz particles, and then dried to obtain the acid leaching concentrate.

[0065] The acid-leached concentrate was calcined at 1050°C in a muffle furnace for 1 hour, and then poured into ultrapure water for water quenching. The high-temperature calcination caused the volume of the quartz to expand and deform. During the quenching process, the fluid inclusions and mineral inclusion impurities inside the quartz were exposed from the inside to the outside, and the lattice impurities such as Al, K, and Na were enriched on the quartz surface, which was conducive to deep impurity removal in the subsequent pickling process.

[0066] The calcined and water-quenched samples were dried and placed in a high-pressure reactor for secondary heating and acid leaching. The mixed acid used was HCl:HNO3:HF=(2~4):1:1, the liquid-solid ratio was 1:2, the leaching temperature was 80℃, and the leaching time was 24 hours. The samples were washed with ultrapure water until neutral, and then ultrasonically washed for 10 minutes to remove impurities on the surface of the quartz particles. The samples were dried and 15 impurities were measured by ICP-OES. After subtraction, the SiO2 content of the high-purity quartz concentrate was 99.9908%.

[0067] 15g of -80+400 mesh fine particles screened from the flotation quartz concentrate were poured into an autoclave and directly subjected to a single acid wash. The acid mixture used was HCl:HNO₃:HF (2-4):1:1, with a liquid-to-solid ratio of 1:2. The leaching temperature was 80°C for 24 hours. Surface impurities were removed by ultrasonic washing for 10 minutes, followed by drying. ICP-OES was used to measure 15 impurities, yielding a 3N7 grade, sub-high-purity quartz concentrate. A second approach employed the same acid wash-calcination-acid wash purification process as for the -40+80 mesh coarse particles. The analysis results for the coarse particles, fine particles, and by-products are shown in Tables 6, 7, 8, and 9.

[0068] Table 6 -40+80 mesh coarse particles pickling-calcining-pickling analysis results

[0069] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9908 51.38 0.76 11.73 <0.01 <0.01 0.1 1.34 element K Li Mg Mn Na Ni Ti Zr Content μg / g 10.91 1.63 2.73 0.01 10.80 <0.01 0.1 0.08

[0070] Table 7 -80+400 mesh fine particles one pickling analysis results

[0071] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9726 61.29 0.87 158.96 <0.01 <0.01 0.12 2.34 element K Li Mg Mn Na Ni Ti Zr Content μg / g 12.8 2.23 24.46 0.04 11.05 <0.01 0.21 0.08

[0072] Table 8 -80+400 mesh fine particles pickling-calcining-pickling analysis results

[0073] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9869 54.74 0.62 45.01 <0.01 <0.01 0.14 1.87 element K Li Mg Mn Na Ni Ti Zr Content μg / g 11.63 1.97 3.27 0.01 11.34 <0.01 0.31 0.09

[0074] In the experiment of Example 1, the SiO2 purity of the coarse particles -40+80 mesh in Table 6 reached 99.9908% after the acid washing-calcination-acid washing purification process, which is greater than 4N, while the SiO2 purity of the fine particles -80+400 mesh was 99.9726% after one acid washing, and reached 99.9869% after the acid washing-calcination-acid washing process.

[0075] Table 9 By-product analysis results (%)

[0076] product Yield <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> Mineral mud 26~32 77.01 11.37 5.23 Magnetic materials 1.6~2 95.92 1.21 0.65 +40 mesh coarse particles 3~4 98.78 0.43 0.17 Flotation of minerals 12~14 97.92 0.45 0.28

[0077] The by-products, such as ore mud, magnetic material, +40 mesh coarse particles and flotation ores, contain high silicon content and can be used as cement ingredients, aerated bricks or new building materials.

[0078] Example 2

[0079] The powdered quartz ore was stirred and scrubbed for 30 minutes without adding a dispersant, and the 400-mesh fine mud was separated by sedimentation. The coarse sand was subjected to magnetic separation-flotation. The flotation quartz concentrate was screened to obtain coarse particles of -40+80 mesh and -80+200 mesh. 15 grams of each sample was weighed and calcined at high temperature in a muffle furnace at 900°C for 1 hour, water quenched, dried, and acid washed, and then calcined again at 1050°C for 1 hour, water quenched, dried, and acid washed again (the acid washing ratio, liquid-solid ratio, etc. were the same as in the example), ultrasonic cleaning was used to further remove impurities on the surface of the quartz particles, and the quartz particles were dried. 15 impurities were measured by ICP-OES. The analysis results of the prepared high-purity quartz concentrate are shown in Tables 10 and 11.

[0080] Table 10 - Analysis results of 40+80 mesh coarse particles after two calcinations and two acid washes

[0081] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9905 50.62 1.08 13.48 0.01 0.01 0.3 2.1 element K Li Mg Mn Na Ni Ti Zr Content μg / g 10.68 1.83 1.98 0.07 12.48 0.01 0.05 0.05

[0082] Table 11 -80+200 mesh twice calcined - twice acid washed analysis results

[0083] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9893 53.84 1.0 21.19 0.01 0.01 0.4 2.65 element K Li Mg Mn Na Ni Ti Zr Content μg / g 11.09 2.16 2.67 0.07 12.09 0.02 0.07 0.06

[0084] In the experiment of Example 2, the results in Tables 10 and 11 show that the SiO2 purity of the coarse particles -40+80 mesh can reach 99.9905% after two calcinations and two acid washes, while the SiO2 purity of the fine particles -80+200 mesh can reach 99.9893% after two calcinations and two acid washes, which cannot reach 4N.

[0085] Example 3

[0086] 400 g of powdered quartz ore was weighed, 600 g / t of phosphate dispersant was added, 400 ml of water was added, and the mixture was stirred and scrubbed for 30 minutes to remove 400 mesh fine mud. The coarse sand was subjected to magnetic separation-flotation, and the flotation quartz concentrate was screened to obtain coarse particles of -40+80 mesh and -80+400 mesh. 50 g of each sample was weighed and calcined at high temperature in a muffle furnace at 900° C. for 1 hour, water quenched, dried, and pickled, and then calcined twice at 1050° C. for 1 hour, water quenched, dried, and pickled twice (the pickling ratio, liquid-solid ratio, etc. were the same as in the example), ultrasonic cleaning was used to further remove impurities on the surface of the quartz particles, and the mixture was dried. 15 impurities were measured by ICP-OES. The analysis results of the prepared high-purity quartz concentrate are shown in Tables 12 and 13.

[0087] Table 12 - Analysis results of 40+80 mesh coarse particles after two calcinations and two acid washes

[0088] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9904 49.96 1.27 14.11 <0.01 <0.01 0.3 2.33 element K Li Mg Mn Na Ni Ti Zr Content μg / g 10.78 1.78 2.14 0.08 11.86 0.01 0.42 0.10

[0089] Table 13 -80+400 mesh twice calcined and twice acid washed analysis results

[0090] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9887 56.47 1.15 21.3 0.01 0.04 0.41 3.7 element K Li Mg Mn Na Ni Ti Zr Content μg / g 11.67 2.17 3.27 0.14 12.29 0.01 0.61 0.13

[0091] In the experiment of Example 3, the results in Tables 12 and 13 show that the SiO2 purity of the coarse particles -40+80 mesh can reach 99.9904% after two calcinations and two acid washes, while the SiO2 purity of the fine particles -80+400 mesh can reach 99.9887% after two calcinations and two acid washes, which cannot reach 4N.

[0092] Example 4

[0093] 400 g of fine quartz ore was weighed, 600 g / t of phosphate dispersant was added, 400 ml of water was added, stirred and scrubbed for 30 minutes, and 400 mesh fine mud was separated by sedimentation to obtain coarse sand. The coarse sand was subjected to a magnetic field strength of 2.0 T to remove magnetic matter. After the non-magnetic matter was screened out and the coarse particles of +40 mesh were removed, flotation was performed to obtain a flotation concentrate. The flotation concentrate of -40+400 mesh was directly pickled, calcined and purified by pickling without classification. The pickling ratio, liquid-solid ratio, calcination temperature, etc. were the same as those in Example 1. The final concentrate was ultrasonically cleaned to further remove impurities on the surface of the quartz particles, dried, and 15 impurities were measured by ICP-OES. The analytical results of the prepared high-purity quartz concentrate are shown in Table 14.

[0094] Table 14 -40+400 mesh pickling-calcining-pickling analysis results

[0095] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9888 55.24 0.75 22.98 <0.01 <0.01 0.13 2.42 element K Li Mg Mn Na Ni Ti Zr Content μg / g 11.24 1.94 4.4 0.04 11.37 0.01 1.43 0.12

[0096] In the experiment of Example 4, the results in Table 14 show that the flotation concentrate -40+400 mesh was directly subjected to acid washing-calcination-acid washing purification without classification, and the SiO2 purity reached 99.9888, but could not reach 4N.

[0097] Example 5

[0098] Weigh 400 g of powdered quartz ore, add 500 g / t of dispersant phosphates and 500 g / t of inorganic strong alkali for synergistic scrubbing and desludging. The slurry concentration is 50%, the scrubbing time is 30 minutes, and the coarse sand is magnetically separated and then flotated. The flotation concentrate is sieved into -40+80 mesh and -40+100 mesh, and then acid washed, calcined, and purified by acid washing. The results are shown in Tables 15 and 16.

[0099] Table 15 -40+80 mesh pickling-calcining-pickling analysis results

[0100] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9913 48.18 0.70 10.96 <0.01 <0.01 0.1 1.34 element K Li Mg Mn Na Ni Ti Zr Content μg / g 10.71 1.61 2.45 0.01 10.58 0.06 0.06 0.04

[0101] Table 16 -40+100 mesh pickling-calcining-pickling analysis results

[0102] element <![CDATA[SiO2 / %]]> Al Ba Ca Co Cr Cu Fe Content μg / g 99.9907 49.43 0.7 11.59 <0.01 <0.01 0.11 1.44 element K Li Mg Mn Na Ni Ti Zr Content μg / g 10.79 1.73 2.69 0.01 10.24 <0.01 0.10 0.10

[0103] The results of the experiments in Example 5, as analyzed in Tables 15 and 16, demonstrate that flotation concentrates classified as -40+80 mesh and -40+100 mesh, followed by pickling, calcination, and then pickling, can yield high-purity quartz concentrates with SiO2 contents exceeding 4N. A comparison of the results in Tables 6 and 15 demonstrates that the synergistic desludging effect of phosphate dispersants and inorganic strong bases is superior to their use alone, and that effective early desludging plays a key role in subsequent purification.

[0104] The above examples show that quartz concentrates of grade 4N can be obtained by classifying flotation quartz concentrate into -40+80 mesh, -40+100 mesh, and then acid washing, calcining, and acid washing, or calcining twice and acid washing twice. However, fine particles of -80+400 mesh or unclassified -40+400 mesh cannot reach 4N grade regardless of acid washing, calcining, and acid washing, or calcining twice and acid washing twice. This indicates that the finer the particle size of fine quartz, the higher the impurity content. Fine particles contain more fluid inclusions and lattice impurities. Calcination can better remove Ca in fluid inclusions. 2+ and Mg 2+ .

[0105] In summary, to reduce purification costs and achieve a higher yield of 4N-grade high-purity quartz concentrate (-40+80 mesh accounts for 26% of the flotation concentrate yield and approximately 15% of the original ore yield, and -40+100 mesh accounts for 41% of the flotation concentrate yield and approximately 25% of the original ore yield), the present invention proposes an optimal purification process for Cambrian fine quartz: dispersant-assisted stirring and scrubbing for desludging, magnetic separation, screening, flotation, and classification to produce -40+100 mesh coarse sand. This process then undergoes an acid wash, calcination, and acid wash purification process to produce a 4N-grade high-purity quartz concentrate. The -100+400 mesh fine particles undergo a single acid wash to produce a 3N7-grade secondary quartz concentrate. This achieves tiered, comprehensive utilization of this Cambrian fine quartz resource and enhances its economic value. High-purity quartz concentrates of varying particle sizes and purities can be produced according to downstream market demand.

Claims

1. A method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz, characterized in that: The following steps are involved: Step 1, ore synergistic dispersant coupled scrubbing: Cambrian pink quartz is used as the selected ore, dispersant and water are added, and scrubbing and stirring are performed in a scrubber to obtain scrubbing slurry; the Cambrian pink quartz is a weathered siliceous raw material that does not require crushing and grinding, and the ore has a SiO2 content of 65.48% to 95.10%, an Al2O3 content of 1.4% to 15.64%, and a Fe2O3 content of 0.56% to 7.06%; Step 2, sedimentation and desliming: Pour the scrub slurry obtained in step 1 into a measuring cylinder, stir it thoroughly and let gravity sedimentation remove the sludge, repeat this desliming process several times until the supernatant is transparent, and obtain quartz coarse sand and sludge; Step 3, strong magnetic separation: the quartz coarse sand material obtained in step 2 is subjected to strong magnetic separation to obtain magnetic and non-magnetic materials; Step 4, screening: the non-magnetic material obtained in step 3 is screened to remove the +40 mesh coarse particles and increase the silicon content of the -40+400 mesh particle size; Step 5, reverse flotation: pour the -40+400 mesh non-magnetic material obtained in step 4 into a flotation machine, adjust the pH of the pulp, add a collector, and perform reverse flotation multiple times to obtain flotation concentrate and middlings; wherein the flotation collector is a mixture of a compound amine, a fatty acid, and a silicate inhibitor; wherein the weight percentage of the compound amine, the fatty acid, and the silicate inhibitor is 7:7:1; Step 6, pickling: the flotation concentrate obtained in step 5 is screened to remove coarse particles of -40+80 mesh, and then pickled and ultrasonically cleaned to obtain acid leaching concentrate; Step 7, calcination, water quenching and pickling: calcining, water quenching and pickling the acid leached concentrate obtained in step 6 to obtain 4N grade high-purity quartz concentrate; Step 8, pickling: the flotation quartz concentrate obtained in step 5 is screened to obtain -80+400 mesh fine particles and then pickled once to prepare 3N7 grade high-purity quartz concentrate; The ore mud obtained in step 2, the magnetic material obtained in step 3, the +40 mesh coarse particles obtained in step 4, and the ores obtained by flotation in step 5 can be made into aerated bricks and building materials.

2. The method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz according to claim 1, characterized in that: In step 1, the dispersant is one or a mixture of inorganic strong bases and phosphates, and the amount of the dispersant is 300-1000 g / t.

3. The method for preparing 4N grade high-purity quartz by purifying Cambrian powder quartz according to claim 1, characterized in that: In step 2, the ore slime is removed by gravity sedimentation, with extraction every 5 minutes and 10 to 14 times, to remove fine slime below 400 mesh.

4. The method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz according to claim 1, characterized in that: In step 3, the strong magnetic separation is wet magnetic separation, the magnetic separation operation is one-stage magnetic separation, and the magnetic field strength is 1.4~2.0T.

5. The method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz according to claim 1, characterized in that: In step 5, the reverse flotation is aeration flotation, and the process conditions are: the pulp concentration is 10-30%, the pulp pH is 2-3, the acid for adjusting the pulp is one of sulfuric acid and hydrofluoric acid or a mixture of the two, the collector dosage is 300-600 g / t, the stirring rate is 1200-1500 r / min, the flotation time is 1-2 min, and multiple flotations are performed until all impurities are selected.

6. The method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz according to claim 1, characterized in that: In step 6, the pickling is carried out using a mixed acid, which is a mixture of nitric acid, hydrochloric acid and hydrofluoric acid, and the leaching time is 4 to 24 hours.

7. The method for purifying Cambrian powder quartz to prepare 4N grade high-purity quartz according to claim 1, characterized in that: In step 7, the calcination conditions are as follows: the temperature of the muffle furnace is raised to 1050° C. for calcination for 1 hour, mixed acid is used for pickling, and the mixed acid is a mixture of nitric acid, hydrochloric acid, and hydrofluoric acid, and the leaching time is 4 to 24 hours.

8. The method for preparing 4N grade high-purity quartz by purifying Cambrian powder quartz according to claim 1, characterized in that: In step 8, the pickling and leaching time is 4 to 24 hours.

9. The method for preparing 4N grade high-purity quartz by purifying Cambrian powder quartz according to claim 1, characterized in that: The waste acid after pickling in step 8 is recovered and used as the acid for pickling in step 6.

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