Method for removing mica through quartz reverse flotation

Abstract

The invention discloses a method for removing mica through quartz reverse flotation, and belongs to the field of high-purity quartz sand preparation, and the method comprises the following steps: adjusting the pH value of quartz sand ore pulp to 5.5-6.5, adding a quartz inhibitor sodium silicate into the quartz sand ore pulp, and stirring; and then adding a collecting agent amino fatty acid compound into the quartz sand ore pulp under the condition of air-blowing stirring, stirring, adding a foaming agent terpenic oil, carrying out reverse flotation, stirring, scraping foam, and washing to obtain the product high-purity quartz sand. According to the method, different adsorptions of quartz and mica are achieved through a novel collecting agent under the weak acid condition, and then the mica is removed through a specific reverse flotation method. The product quartz sand obtained after reverse flotation is high in purity, and the content of aluminum oxide impurities is reduced to 100 ppm or below.

Description

Technical Field

[0001] The invention belongs to the field of high-purity quartz sand preparation, and in particular relates to a method for removing mica by reverse flotation of quartz. Background Art

[0002] High-purity quartz products have excellent physical and chemical properties such as high temperature resistance, corrosion resistance, low thermal expansion, high insulation and light transmittance, and are therefore widely used in the fields of optical fiber communications, solar photovoltaics, aerospace, electronics and semiconductors. As an irreplaceable basic raw material in the preparation of high-purity quartz products, high-purity quartz sand has been listed as a strategic non-metallic mineral, suitable for a new generation of new technologies and new materials, and its preparation and purification process is therefore of great research significance.

[0003] Considering the economic value and the difficulty of purification process, the beneficiation of high-purity quartz sand is mainly based on quartz-rich ores, including vein quartz, granite pegmatite, etc. Although these ores have different ore components due to different regions and locations, quartz ore is usually accompanied by mica, including black and white mica, potassium mica, sodium mica, etc., and the presence of these mica often increases the difficulty of quartz sand purification.

[0004] Common methods for removing mica include air separation, gravity separation, flotation, acid leaching, etc. The most commonly used method in the field of high-purity quartz sand is flotation, which can be divided into acid floating mica method, neutral floating mica method and alkaline floating quartz method. The most commonly used flotation separation method in industry is the first type: acid floating mica method. It is further divided into fluorine-containing acid flotation method and fluorine-free acid flotation method. Whether it is the acid floating mica method or the alkaline floating quartz method, strong acid and alkali conditions will not only corrode the flotation equipment and pollute the environment, but also pose a threat to the safety of operators. Therefore, in recent years, the development of flotation processes with mild conditions (i.e., neutral floating mica method) has received more and more attention. Due to the lack of efficient mica collectors in related flotation research, the flotation separation effect of a single collector in the current neutral flotation mica process is relatively poor, and it is usually necessary to use a variety of mixed collectors, and some even require additional activators (such as calcium chloride, etc.) to increase the flotation difference between quartz and mica. Therefore, there is a real and urgent need to develop flotation agents with stronger mica capture capabilities to separate mica from quartz under mild conditions.

[0005] Patent application with publication number CN103736596A discloses a technology for removing mica by quartz direct flotation. This method first adds sodium carbonate to adjust the pulp to make the pulp alkaline, and then adds one or more of a variety of collectors such as sodium N-acyl sarcosinate, cyclohexane acid soap, oxidized paraffin soap, oleic acid and hydroxamic acid to make the quartz float, and the product obtained in the tank is mica.

[0006] A patent application with publication number CN105618271A discloses a method for separating quartz from low-grade potassium sodium mica ore by positive flotation. Sodium carbonate or sodium hydroxide is added to the ore pulp to adjust the slurry to an alkaline condition of pH 8 to 10, and then alkaline earth metal ions such as calcium chloride, lime or barium chloride are used to activate the quartz, sodium dodecyl sulfate, water glass and sodium hexametaphosphate are used as inhibitors, and amine collectors such as dodecylamine, octadecylamine and etheramine are used to float the quartz, thereby separating quartz and mica.

[0007] The patent application with publication number CN 107899753A discloses a fluorine-free flotation separation of quartz and mica using an anionic combined collector, which uses NaOH as a pH regulator to float quartz under alkaline conditions, and also adds CaCl2 as an activator, and also needs to dissolve the collector in warm water at 50°C to 60°C. The positive flotation methods of the above inventions all need to be carried out under alkaline conditions, which can pollute the environment. In addition, many types of reagents are required, and the operation is cumbersome. Due to the harsh process conditions, it is difficult to apply in actual industrial production.

[0008] On this basis, some researchers have further developed a flotation separation method with mild conditions: the neutral floating mica method. The patent application with publication number CN108580050A discloses a method for flotation of potassium mica under neutral pH conditions, in which sodium oleate is added to the pulp as a collector, amine substances such as dodecylamine as activators, sodium hexametaphosphate or water glass as inhibitors, and potassium mica is floated during flotation to achieve separation from quartz. However, the price of the collector sodium oleate is not low, and it is necessary to add 1000-1600g / T of the collector containing potassium mica material, which is a relatively large amount. In addition, sodium oleate is unstable and is prone to corruption and deterioration after being placed for a long time. It is also easy to generate insoluble calcium and magnesium soap precipitation with calcium and magnesium salts in hard water, and the liquid becomes milky. Although the purity of the mica separated by this method is good, the purity of the separated quartz phase is not guaranteed.

[0009] The patent application with publication number CN118142713A discloses a method for flotation removal of mica and purification of quartz from mica quartz ore under neutral conditions. The mica quartz ore with a dual composite structure of mica and quartz is used as raw material, and quartz and mica mixed sand is obtained through crushing pretreatment, calcination, heat preservation, water quenching, crushing, screening, magnetic separation and other steps. Under neutral conditions, cationic flotation agents polyetheramine D230, polyetheramine D400 and polyetheramine D2000 with diamine and polyether structures are used as collectors to carry out multiple flotation enrichment of quartz phase, remove mica and other impurity phases, and obtain purified quartz. The method does not use acid or alkali in the flotation process, and the flotation process belongs to the positive flotation of quartz. It is a new method different from the traditional reverse flotation to remove mica and other impurity phases from quartz phase. Summary of the invention

[0010] The invention provides a method for removing mica by reverse flotation of quartz, which has simple and efficient steps. First, water glass, a quartz inhibitor, is added under weakly acidic conditions to reduce the floating of quartz, and then a new mica collector, amino fatty acid compound, is added to efficiently capture mica, thereby realizing the separation of quartz and mica. In order to compensate for the problem of weak foaming of the new collector, pine oil, a foaming agent, needs to be added to prolong the foaming time of flotation. The content of alumina in the quartz sand obtained after reverse flotation is reduced to below 100ppm.

[0011] The specific technical solutions adopted are as follows:

[0012] A method for removing mica by reverse flotation of quartz, comprising the steps of:

[0013] The pH value of the quartz sand slurry is adjusted to 5.5-6.5 with sulfuric acid, and water glass as a quartz inhibitor is added thereto, and stirred; then a mica collector is added to the quartz sand slurry under aeration stirring conditions, stirred, and then a frother is added for reverse flotation, stirred and scraped, and quartz sand with a low mica content is obtained after washing.

[0014] Furthermore, the quartz sand in the quartz sand slurry is obtained by pre-treating quartz ore, wherein the SiO2 content in the quartz ore is ≥70%, and the pre-treatment comprises crushing, grinding, washing and magnetic separation of the quartz ore.

[0015] Furthermore, in the quartz ore, the quartz content is 70% to 90%, and the total mica content is 10% to 20%, including biotite, muscovite, lepidolite, and the like.

[0016] Furthermore, the quartz sand particle size in the quartz sand slurry is 60-100 meshes, and the mass concentration of the quartz sand slurry is 60-70wt%.

[0017] Furthermore, sulfuric acid is used to adjust the pH value of the quartz sand slurry to 5.5-6.5.

[0018] The order of adding reagents in the flotation process is crucial. In order to ensure the effective separation of quartz and mica, it is necessary to add quartz inhibitor before adding collector, so as to reduce the interaction between collector and quartz and realize the flotation separation of quartz and mica to the greatest extent.

[0019] Preferably, the quartz inhibitor is water glass, and the amount added is 100-200 g / t based on the solid mass in the quartz sand slurry.

[0020] The mica collector is an amino fatty carboxylic acid compound, the compound structure of which includes a hydrophobic straight-chain alkane with more than ten carbon atoms, an amino group and a carboxyl group at the end, and the mica collector has the following structure:

[0021]

[0022] Among them, n=1-5.

[0023] Under weakly acidic conditions, the terminal amino group in the novel collector amino fatty carboxylic acid compounds preferentially adsorbs on the negatively charged surface of mica and quartz. The longer straight chain structure gives the collector good spatial curvature, and the carboxyl group at the other end of the molecule can effectively adsorb on the positively charged surface of mica (such as Al 3+ , K + 、Na + Since the quartz surface lacks effective positive charge areas, the carboxyl groups in the collector molecules will not be adsorbed on the quartz surface. Therefore, the new collector has a stronger adsorption force on mica, thereby achieving highly selective flotation separation of mica and quartz.

[0024] Furthermore, the amount of mica collector added is 40-60 g / t based on the solid mass in the quartz sand slurry. Too little collector addition will result in poor separation of mica and quartz, while too much collector addition will cause part of the quartz sand to float up with the mica, affecting the recovery rate.

[0025] Furthermore, the foaming agent is pine oil, and the amount of the foaming agent added is 10-20 g / t based on the solid mass in the quartz sand slurry.

[0026] Preferably, the method of removing mica by quartz reverse flotation is repeated at least once to further improve the purity of the product quartz sand.

[0027] Preferably, the SiO2 content in the obtained quartz sand with low mica content is ≥99.9%, and the Al2O3 content is ≤0.1% ppm.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention adopts a reverse flotation strategy for minerals with high quartz content, which is superior to the forward flotation strategy in reducing the amount of reagents used and improving the flotation effect.

[0030] (2) The present invention uses a novel amino fatty acid compound as a collector for mica. The collector is adsorbed on different positions on the surface of mica through the synergistic effect of amino and carboxyl groups, wherein the synergistic effect between the two groups in the molecule can further enhance the adsorption capacity of the collector on mica; at the same time, due to the long, bendable fatty chain between the two groups, the combination of amino, carboxyl and mica is more flexible and diverse.

[0031] (3) The new collector used in the present invention has a greater mica collection capacity than the traditional single or mixed collectors, and the effect of reverse flotation separation of quartz and mica by the collector is better than the flotation effect of using a single or mixed collector.

[0032] (4) The medicine used in the present invention is cheap and has a wide source of raw materials.

[0033] (5) The reverse flotation process of the present invention is carried out under weakly acidic conditions, avoiding the traditional strong acid and strong alkali conditions, thereby reducing the harm of the flotation process to production equipment and operators. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The present invention will be further described below in conjunction with specific implementation modes.

[0036] Example 1

[0037] 1. Mineral raw materials:

[0038] After quantitative analysis such as XRD, the quartz content in the quartz ore is 70.27%, the biotite content is 10.27%, the muscovite content is 7.03%, and the feldspar content is 2.42%. Phase analysis shows that the ore mainly contains quartz, mica, and feldspar.

[0039] 2. Flotation reagents and operating conditions:

[0040] Pretreatment process: crush the quartz ore into particles with a crusher; grind the particles into 60-100 meshes in a wet mill, add water to the quartz sand, wash it in a scrubber, and dry it in a vacuum dryer after washing; the dried quartz sand enters a magnetic separator for magnetic separation to remove magnetic impurities and obtain preliminarily purified quartz sand;

[0041] Reverse flotation process: first rinse the preliminarily purified quartz sand once with hot water, prepare it into a quartz sand slurry with a mass concentration of 70wt%, then adjust the slurry pH value to 5.5 with sulfuric acid, add quartz inhibitor water glass 100g / t to the slurry, stir for 5 minutes, then continue to add mica collector amino fatty acid compound 60g / t, stir for 5 minutes; add frother pine oil 20g / t to the slurry under the condition of aeration and stirring, perform quartz reverse flotation on the ore, float for 30 minutes, stir and scrape bubbles during the process, rinse the obtained quartz sand with deionized water two to three times after flotation, wash away the reagent residue on the surface of the mineral, repeat the above process once, and obtain the product quartz sand;

[0042] The test results show that quartz minerals can be effectively recovered according to the above process parameters and reagent conditions. After a single flotation, the quartz recovery rate is 79.25%, and high-purity quartz sand with a grade (SiO2 content) of 99.91% is obtained. At the same time, the Al2O3 content is reduced to 0.07%, indicating that the mica content is relatively low.

[0043] Example 2

[0044] 1. Mineral raw materials:

[0045] After quantitative analysis such as XRD, the quartz content in the quartz ore is 85.19%, the biotite content is 4.27%, the muscovite content is 9.89%, and the feldspar content is 0.65%. Phase analysis shows that the ore mainly contains quartz, mica, and feldspar.

[0046] 2. Flotation reagents and operating conditions:

[0047] The pretreatment process is the same as in Example 1;

[0048] Reverse flotation process: first rinse the preliminarily purified quartz sand once with hot water, prepare it into a quartz sand slurry with a mass concentration of 60wt%, then adjust the slurry pH value to 6.0 with sulfuric acid, add quartz inhibitor water glass 200g / t to the slurry, stir for 5 minutes, then continue to add mica collector amino fatty acid compound 40g / t, stir for 5 minutes; add frother pine oil 10g / t to the slurry under the condition of aeration and stirring, perform quartz reverse flotation on the ore, float for 20 minutes, stir and scrape bubbles during the process, rinse the obtained quartz sand with deionized water two to three times after flotation, wash away the reagent residue on the surface of the mineral, repeat the above process once, and obtain the product quartz sand;

[0049] The test results show that according to the above process parameters and reagent conditions, quartz minerals can be effectively recovered with a recovery rate of 84.25%, and high-purity quartz sand with a grade (SiO2 content) of 99.94% is obtained. At the same time, the Al2O3 content is reduced to 0.05%, indicating that the mica content is extremely small.

[0050] Example 3

[0051] 1. Mineral raw materials:

[0052] After precise quantitative analysis, the quartz content in the quartz ore is 75.22%, the biotite content is 4.14%, the muscovite content is 5.89%, the lithium mica content is 12.15%, and the feldspar content is 1.77%. Phase analysis shows that the ore mainly contains quartz, mica and feldspar.

[0053] 2. Flotation reagents and operating conditions:

[0054] The pretreatment process is the same as in Example 1;

[0055] Reverse flotation process: first rinse the preliminarily purified quartz sand once with hot water, prepare it into a quartz sand slurry with a mass concentration of 70wt%, then adjust the slurry pH value to 6.5 with sulfuric acid, add quartz inhibitor water glass 100g / t to the slurry, stir for 5 minutes, then continue to add mica collector amino fatty acid compound 60g / t, stir for 5 minutes; add frother pine oil 20g / t to the slurry under the condition of aeration and stirring, perform quartz reverse flotation on the ore, float for 30 minutes, stir and scrape bubbles during the process, rinse the obtained quartz sand with deionized water two to three times after flotation, wash away the reagent residue on the surface of the mineral, repeat the above process once, and obtain the product quartz sand;

[0056] The test results show that according to the above process parameters and reagent conditions, quartz minerals can be effectively recovered, with a recovery rate of 81.25%, and high-purity quartz sand with a grade (SiO2 content) of 99.90% is obtained. At the same time, the Al2O3 content is reduced to 0.08%, indicating that the mica content is relatively low.

[0057] Comparative Example 1

[0058] The only difference between this comparative example and Example 1 is that no quartz inhibitor water glass is added to the flotation reagent.

[0059] The test results show that although the absence of quartz inhibitor water glass will not affect the grade of quartz, it will reduce the recovery rate of quartz, which is 68.29%; high-purity quartz sand with a grade (SiO2 content) of 99.91% is obtained, and the Al2O3 content is reduced to 0.07%.

[0060] Comparative Example 2

[0061] The difference between this comparative example and Example 1 is that the novel mica collector amino fatty acid compound is replaced by an equal amount of dodecylamine and fatty acid.

[0062] The test results show that the replaced reagent combination has poor flotation effect under the same conditions, with a recovery rate of 87.68%, and high-purity quartz sand with a grade (SiO2 content) of 82.34%, while the mica content exceeds 10%.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 1 is that the foaming agent pine oil is not added.

[0065] The test results show that the failure to add pine oil results in less foam and shorter flotation time, and flotation cannot be carried out effectively.

[0066] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for removing mica by reverse flotation of quartz, characterized in that: The method comprises the following steps: adjusting the pH value of quartz sand slurry to 5.5-6.5 by using sulfuric acid, adding quartz inhibitor water glass thereto, and stirring; then adding a mica collector to the quartz sand slurry under the condition of aeration and stirring, stirring, adding a frother for reverse flotation, stirring and scraping bubbles, and washing to obtain quartz sand with a low mica content; The mica collector is an amino fatty carboxylic acid compound, which contains a straight-chain alkane with more than ten carbon atoms, an amino group and a carboxyl group at the end, and has the following structure: Among them, n=1-5.

2. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The quartz sand in the quartz sand slurry is obtained by pre-treating quartz ore, wherein the SiO2 content of the quartz ore is ≥70%, and the pre-treatment comprises crushing, grinding, screening, washing and magnetic separation of the quartz ore.

3. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The particle size of the quartz sand in the quartz sand slurry is 60-100 meshes, and the mass concentration of the quartz sand slurry is 60-70wt%.

4. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: Sulfuric acid is used to adjust the pH value of the quartz sand slurry to 5.5-6.

5.

5. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The amount of the mica collector added is 40-60 g / t based on the solid mass in the quartz sand slurry.

6. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The amount of the quartz inhibitor added is 100-200 g / t based on the solid mass in the quartz sand slurry.

7. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The foaming agent is pine oil, and the amount of the foaming agent added is 10-20 g / t based on the solid mass in the quartz sand slurry.

8. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The method of removing mica by reverse flotation of quartz is repeated at least once.

9. The method for removing mica by quartz reverse flotation according to claim 1, characterized in that: The obtained quartz sand with low mica content has a SiO2 content of ≥99.9% and an Al2O3 content of ≤0.2%.

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