A method for preparing quartz powder by removing impurities and purifying decomposed granite

Abstract

The present invention discloses a method for preparing quartz concentrate by removing impurities and purifying decomposed granite. The method specifically comprises: stirring and slurry mixing, classification, grinding, desludging, and multi-stage reverse flotation. The present invention uses a high-efficiency combined collector with a specific ratio during the reverse flotation process. While ensuring the quartz recovery rate, it can also improve the removal rate of feldspar impurities and enhance the grade of the quartz concentrate product. The high-efficiency combined collector is composed of dodecylamine, sodium dodecylsulfonate, and benzohydroxamic acid in a mass ratio of 5:1:(0.8-1.0). The method of the present invention is of great significance for the recycling and utilization of decomposed granite resources.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a method for preparing quartz concentrate by removing impurities and purifying weathered granite. Background Art

[0002] Granite is hard, corrosion-resistant, strong, heat-resistant, wear-resistant, and has low water absorption, making it a high-quality building and decorative stone. Widely distributed and abundant in reserves worldwide, granite is primarily used in industries such as construction, artwork, chemicals, ceramics, and liquid crystal displays. Weathered granite is a layer of soil formed above the original rock layer as a result of long-term chemical changes caused by physical weathering and the exposure to impure surface water (such as carbonic acid-containing rainwater, river water, seawater, and groundwater). Its primary mineral components include feldspar, quartz, mica, and clay minerals such as kaolinite. Weathered granite is currently primarily used to enrich feldspar and is an important raw material for the ceramic and glass industries. In fact, weathered granite also contains a high content of quartz and a fine crystal structure. Due to its hardness and strong weathering resistance, it can be recycled as a quartz resource.

[0003] The basic structural unit of quartz is the silicon-oxygen tetrahedron. It is chemically stable, corrosion-resistant, heat-resistant, has a low coefficient of thermal expansion, is highly insulating, and possesses unique optical properties. Quartz products are widely used in industries such as ceramics, glass, chemicals, electronics, and semiconductors. However, with increasing demand for resources, high-quality quartz resources are increasingly insufficient to meet these demands. Therefore, the utilization of lower-grade quartz resources has become increasingly important.

[0004] The impurities in traditional quartz ore generally include feldspar, mica, tourmaline, clay minerals, etc., which are similar to those in weathered granite. Among them, feldspar is the most important impurity mineral affecting the purity of quartz because it has a structure and physicochemical properties that are very similar to those of quartz, and it is also the current research difficulty. The most widely used quartz collectors currently include anionic collectors and cationic collectors. Cationic collectors usually include amine collectors such as dodecylamine and octadecylamine, and anionic collectors usually include sulfonate collectors, sulfate collectors, oleic acid collectors, etc. In order to improve the separation efficiency of feldspar and quartz, HF is usually used as an activator for feldspar, which is extremely harmful to the environment. Therefore, it is urgent to provide a method for separating feldspar and quartz in weathered granite that is environmentally friendly and efficient. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing quartz powder by removing impurities and purifying weathered granite, so as to solve the current problems of difficulty in separating feldspar and quartz and low utilization efficiency of weathered granite.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The method for preparing quartz powder by removing impurities and purifying decomposed granite provided by the present invention comprises the following steps:

[0008] S1. Stirring, slurrying and classifying the decomposed granite ore to obtain a quartz pre-enriched product;

[0009] S2. The quartz pre-enriched product is ground and desludged to obtain a coarse-grained mineral;

[0010] S3. The coarse-grained minerals are subjected to roughing and scavenging to obtain quartz concentrate.

[0011] Furthermore, the step S1 further includes: during the process of stirring and slurrying the weathered granite ore, adding a dispersant to fully disperse the slurry, and then classifying the slurry.

[0012] Furthermore, the dispersant is sodium hexametaphosphate, sodium silicate, sodium carbonate, etc.; the amount of the dispersant is 300-600 g / t, preferably 500 g / t.

[0013] Furthermore, in step S1, the stirring speed of the slurry mixing is 1000-1500 r / min, preferably 1200 r / min; the classification adopts wet screening with a mesh size of 60-80 mesh, preferably 80 mesh, and the obtained screen product is a quartz pre-enriched product.

[0014] Furthermore, in step S2, the content of the product particle size after grinding is -200 mesh accounts for 70%-80%.

[0015] Furthermore, in step S3, the roughing is a first-stage roughing; the first-stage roughing is reverse flotation, and the specific reagent system used is:

[0016] The adjusting agent is hydrochloric acid + oxalic acid, and the pH value of the pulp is adjusted to 2.5-3.0;

[0017] The inhibitor is sodium silicate, and the dosage is 800-1200g / t, preferably 1000g / t;

[0018] The collector is dodecylamine, and the dosage is 200-300 g / t, preferably 200 g / t.

[0019] Furthermore, in step S3, the sweeping is a four-stage sweeping; the four-stage sweeping is all reverse flotation, and the specific reagent system used is:

[0020] Sweep 1: The adjusting agent is hydrochloric acid + oxalic acid, and the pH value of the pulp is adjusted to 2-3; the inhibitor is sodium silicate, and the dosage is 800-1200g / t, preferably 1200g / t; the collector is a combined collector, and the dosage is 400-600g / t, preferably 560g / t;

[0021] Sweep 2: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200-300 g / t, preferably 280 g / t;

[0022] Sweep 3: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200-300 g / t, preferably 280 g / t;

[0023] Sweep 4: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200-300 g / t, preferably 280 g / t.

[0024] Furthermore, the combined collector is composed of dodecylamine, sodium dodecylsulfonate and benzohydroxamic acid in a mass ratio of 5:1:(0.8-1.0), preferably 5:1:1.

[0025] Furthermore, the combination collector is added as follows: first, sodium dodecylsulfonate and benzohydroxamic acid in the combination collector are prepared into an anionic collector solution according to a preset ratio, and dodecylamine is prepared into a cationic collector solution, and then the cationic collector solution is first added to the ore pulp, and then the anionic collector solution is added.

[0026] It should be noted that the present invention adjusts the pH to 2-3 with a strong acid, near the zero-electric point of quartz. At this time, the quartz surface is almost uncharged or positively charged, and the feldspar surface is negatively charged. When the cationic collector dodecylamine enters the slurry, it will be preferentially adsorbed on the feldspar surface, increasing the hydrophobicity of the feldspar. At this time, an anionic collector is added. The anionic collector will react with the dodecylamine adsorbed on the feldspar surface to increase the floatability of the feldspar, causing it to float and be selected. Benzohydroxamic acid is currently an important collector in bauxite beneficiation. It is an anionic surfactant with both high selectivity and high collecting properties. This experiment found that benzohydroxamic acid can enhance the adsorption of dodecylamine on the feldspar surface by sodium dodecyl sulfate, thereby improving the separation efficiency of feldspar and quartz.

[0027] Furthermore, the anionic collector solution is prepared by adding sodium dodecylsulfonate and benzohydroxamic acid to warm water at 40-50°C under normal pressure to obtain an anionic collector solution; the cationic collector solution is prepared by adding dodecylamine to weakly acidic warm water at 40-50°C under normal pressure to obtain a cationic collector solution.

[0028] Furthermore, the step S3 further includes: beneficiating the scavenged ore to obtain high-quality feldspar products.

[0029] Based on the same inventive concept, the present invention also provides an application of the quartz fine powder, which is used in silicon micropowder manufacturing, metallurgy or food industry, chemical and chemical raw materials, etc.

[0030] Principle of the present invention:

[0031] 1) The main components of the granite weathered sand layer are quartz, kaolin, feldspar, mica, iron oxides, and other impurity oxides. The present invention pre-sets slurry adjustment and classification based on the weathering characteristics of granite. During the weathering process, quartz has relatively high hardness and relatively stable properties, so the coarse-grained fraction contains a large proportion of quartz. Through classification, some muddy impurities such as kaolin, feldspar, and iron oxides can be removed in advance.

[0032] 2) Under acidic conditions, mica, kaolin and most iron oxide impurities can be removed through roughing, and the remaining potassium feldspar and sodium feldspar are the key factors affecting the grade of quartz;

[0033] 3) The mechanism of fluorine-free flotation is: under strongly acidic pH values, especially near the zero charge point of quartz, the surface of feldspar is negatively charged while the surface of quartz is uncharged. Although this difference is subtle, the activation of feldspar by the activator and the inhibition of quartz by the inhibitor are sufficient to enable the amine collector to be preferentially adsorbed on the surface of feldspar. The adsorbed amine collector then complexes with the anionic collector, increasing the hydrophobicity of the feldspar surface and achieving the purpose of feldspar separation.

[0034] Beneficial effects of the present invention:

[0035] 1) The present invention pre-enriches quartz according to the weathering characteristics of granite through slurry adjustment and pre-classification, greatly reducing the cost of mineral processing;

[0036] 2) The present invention uses oxalic acid instead of hydrofluoric acid as an activator, which can increase the electronegativity of the feldspar surface and increase the flotation difference between feldspar and quartz with less damage to the environment;

[0037] 3) Benzohydroxamic acid is usually only used in the flotation of heavy metal oxide ores such as scheelite and wolframite. The present invention found that it has a good synergistic effect with sodium dodecyl sulfate in the flotation separation of feldspar and quartz;

[0038] 4) The present invention uses dodecylamine, which has a strong collecting ability, as the main collector, adds sodium dodecylsulfonate and benzohydroxamic acid, which have both selectivity and collecting ability, as auxiliary collectors, and adds oxalic acid as a surfactant for feldspar. This combined collector can not only improve the grade of the quartz concentrate obtained by separation but also ensure the recovery rate, which is of great significance for the recycling of weathered granite.

[0039] 5) In addition to the high-value utilization of the final quartz product, the middlings in this product process can eventually be reused through magnetic separation and flotation to obtain kaolin and feldspar products, achieving zero tail emissions. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0041] Figure 2 The present invention relates to a flotation flow chart. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, they will be described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0043] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0044] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0045] Example 1

[0046] The raw ore used in this example is weathered granite overburden sand, in which the SiO2 content is 64.45%, the Al2O3 content is 30.85%, and the Fe2O3 content is 2.03%. Figure 1 The process shown in the figure uses the high-efficiency combined collector provided by the present invention to carry out a quality improvement and impurity removal test. The specific steps are as follows:

[0047] 1) Prepare slurry from the raw ore, add 500g / t sodium hexametaphosphate into the slurry, and stir to fully disperse the slurry;

[0048] 2) Classifying the slurry using a wet screen with a mesh size of 80 to obtain a quartz pre-enriched product;

[0049] 3) Grinding the quartz pre-enriched product using a ball mill to obtain a ground product, wherein the content of the ground product having a particle size of -200 mesh accounts for 75%;

[0050] 4) Use a hydrocyclone or wet screen to hydraulically classify the ground product to remove muddy minerals and obtain coarse-grained minerals;

[0051] 5) Add hydrochloric acid + oxalic acid to the coarse-grained mineral to adjust the pH value of the pulp to 2.5-3.0, then add 1000 g / t of sodium silicate and 200 g / t of dodecylamine to perform roughing to obtain roughing concentrate and roughing tailings;

[0052] 6) Add hydrochloric acid and oxalic acid to the roughing tailings to adjust the pulp pH to 2-3, then add sodium silicate and a high-efficiency combined collector to perform four-stage scavenging to ultimately obtain quartz concentrate and feldspar middlings. The reagent systems for the four-stage scavenging are:

[0053] Sweep 1: Sodium silicate 1200g / t, high-efficiency combined collector 560g / t;

[0054] Sweep 2: Sodium silicate 1200g / t, high-efficiency combined collector 280g / t;

[0055] Sweep three: sodium silicate 1200g / t, high-efficiency combined collector 280g / t;

[0056] Sweep 4: Sodium silicate 1200g / t, high-efficiency combined collector 280g / t;

[0057] Among them, the high-efficiency combined collector is composed of dodecylamine, sodium dodecylsulfonate and benzohydroxamic acid in a mass ratio of 5:1:1. The method of adding the high-efficiency combined collector is: first, sodium dodecylsulfonate and benzohydroxamic acid are added to warm water at 40-50°C under normal pressure to prepare an anionic collector solution; dodecylamine is added to weakly acidic warm water at 40-50°C to prepare a cationic collector solution; then the cationic collector solution is added to the ore pulp first, and then the anionic collector solution is added.

[0058] The final quartz concentrate product obtained had a yield of 26.116%, a recovery rate of 40.24%, and a grade of 99.75%. The main components of the product are shown in Table 1.

[0059] Table 1 Quartz concentrate product composition test results

[0060]

[0061] Example 2

[0062] Compared with Example 1, this Example differs only in that the mass ratios of dodecylamine, sodium dodecylsulfonate, and benzohydroxamic acid in the high-efficiency combined collector are different. Specifically, the mass ratios of dodecylamine, sodium dodecylsulfonate, and benzohydroxamic acid are 5:1:0.4, 5:1:0.6, 5:1:0.8, and 5:1:1.2, respectively. The experimental results are shown in Table 2.

[0063] Table 2 XRF analysis results of quartz product collector combination test

[0064]

[0065] Taking into account the feldspar potassium and aluminum removal rates and product flotation yield, the best separation effect of quartz and feldspar was achieved when the mass ratio of dodecylamine, sodium dodecylsulfonate and benzohydroxamic acid was 5:1:(0.8-1).

[0066] Comparative Example 1

[0067] Compared with Example 1, this comparative example differs in that the high-efficiency combined collector is a composite collector composed of dodecylamine and sodium dodecylsulfonate in a mass ratio of 3:1. The remaining steps and reagent dosages remain unchanged. The resulting quartz concentrate has a grade of 93.85%, a yield of 30%, and a recovery of 43%. The main components of the quartz concentrate are shown in Table 3.

[0068] Table 3 Quartz concentrate product composition test results

[0069]

[0070] In summary, the application method of the high-efficiency combined collector provided by the present invention in the flotation separation of feldspar and quartz can greatly improve the grade of SiO2 in the mine and the recycling value of weathered granite while ensuring the recovery rate as much as possible.

[0071] 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 preparing quartz powder by removing impurities and purifying decomposed granite, comprising the following steps: S1. Stirring, slurrying and classifying the decomposed granite ore to obtain a quartz pre-enriched product; S2. The quartz pre-enriched product is ground and desludged to obtain a coarse-grained mineral; S3. The coarse-grained minerals are subjected to roughing and scavenging to obtain quartz powder; In step S3, the sweeping is a four-stage sweeping; the four-stage sweeping is all reverse flotation, and the specific reagent system used is: Sweep 1: The adjusting agent is hydrochloric acid + oxalic acid, and the pH of the pulp is adjusted to 2-3; the inhibitor is sodium silicate, and the dosage is 800-1200g / t; the collector is a combined collector, and the dosage is 400-600g / t; Sweep 2: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200~300g / t; Sweep 3: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200~300g / t; Sweep 4: The reagents are the same as those in Sweep 1, the pH and the dosage of the inhibitor are the same as those in Sweep 1, and the dosage of the collector is 200~300g / t; The combined collector is composed of dodecylamine, sodium dodecylsulfonate and benzohydroxamic acid in a mass ratio of 5:1:(0.8-1.0).

2. The method according to claim 1, characterized in that The step S1 further includes: during the process of stirring and slurrying the weathered granite ore, adding a dispersant to fully disperse the slurry, and then classifying the slurry.

3. The method according to claim 2, characterized in that The dispersant is at least one of sodium hexametaphosphate, sodium carbonate, and sodium silicate, and the dosage is 300-600 g / t.

4. The method according to claim 1, wherein In step S1, the stirring speed of the slurry mixing is 1000-1500 r / min; the classification adopts wet screening with a mesh size of 60-80 mesh, and the obtained screen product is a quartz pre-enrichment product.

5. The method according to claim 1, wherein In the step S2, the content of the product particle size after grinding is -200 mesh accounts for 70%-80%.

6. The method according to claim 1, wherein In step S3, the roughing is a first-stage roughing; the first-stage roughing is reverse flotation, and the specific reagent system used is: The adjusting agent is hydrochloric acid + oxalic acid, and the pH value of the pulp is adjusted to 2.5-3.0; The inhibitor is sodium silicate, and the dosage is 800-1200g / t; The collector is dodecylamine, and the dosage is 200-300g / t.

7. The method according to claim 1, characterized in that The combined collector is added as follows: first, sodium dodecylsulfonate and benzohydroxamic acid in the combined collector are mixed into an anionic collector solution according to a preset ratio, and dodecylamine is mixed into a cationic collector solution; then, the cationic collector solution is first added into the ore pulp, and then the anionic collector solution is added.

8. The method according to claim 7, characterized in that The anionic collector solution is prepared by adding sodium dodecylsulfonate and benzohydroxamic acid to warm water at 40-50°C under normal pressure to obtain an anionic collector solution; the cationic collector solution is prepared by adding dodecylamine to weakly acidic warm water at 40-50°C under normal pressure to obtain a cationic collector solution.

9. The method according to claim 1, characterized in that The step S3 further includes: beneficiating the scavenged ore to obtain high-quality feldspar products.

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