A method for deeply purifying quartz sand

Abstract

The application discloses a method for deeply purifying quartz sand. First, coarse quartz particles are ground to obtain samples with a particle size of-0.6+0.1 mm, and then magnetic separation is performed to obtain a magnetic separation concentrate; the magnetic separation concentrate is subjected to multiple reverse flotation to remove gangue minerals, thereby obtaining a flotation concentrate; the flotation concentrate is subjected to grinding treatment, wherein the grinding speed is 50-250 r / min, the grinding time is 5-90 min, and the grinding concentration is 50-70%; after the grinding treatment is completed, the samples are screened, the-0.6+0.1 mm particle size is taken as the grinding concentrate, and the-0.1 mm particle size is taken as the tailings, thereby completing the deep purification of the quartz sand. The application can effectively remove the un-dissociated gangue mineral intergrowth in the substandard quartz sand after the conventional beneficiation, thereby improving the grade of the quartz.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of material purification, and particularly relates to a method for deep purification of quartz sand. BACKGROUND

[0002] Quartz is a typical non-metallic mineral commonly found in nature and widely used, and is also an important rock-forming mineral, and the main component of quartz is SiO2. Due to its unique crystal structure and chemical composition, quartz has characteristics such as hard texture, high temperature resistance, corrosion resistance, good light transmission and good insulation. These characteristics make quartz have typical characteristics of one mineral with multiple uses, and are widely used in glass industry, building industry, ceramic industry, electronics and electrical industry, aerospace, solar photovoltaic, semiconductor and other important fields, and are an important raw material for the development of China's industry.

[0003] Quartz has strict requirements on particle size in different fields of application, for example, in the glass industry, high-purity quartz and other fields, it is usually required that the particle size of quartz sand is-0.6+0.1 mm. In the purification process of quartz, grinding is mainly to dissociate quartz and gangue minerals and to reach the corresponding separation particle size range. Commonly used grinding equipment in quartz grinding mainly includes ball mill, rod mill and autogenous mill.

[0004] With the development and utilization of quartz resources, high-quality quartz resources are gradually exhausted, and efficient utilization of low-quality quartz is gradually valued. Low-quality quartz often occurs with gangue minerals, and if the traditional grinding method is used to fully dissociate quartz and gangue minerals, the grinding fineness will be too fine, resulting in a significant reduction in the yield of available quartz sand. In order to ensure the relatively coarse particle size requirement of quartz sand application, it is also impossible to fully dissociate quartz and gangue minerals, which is the problem of low-quality quartz that is difficult to be efficiently utilized.

[0005] After grinding, the quartz particles are often accompanied by intergrowth impurities. Such undissociated intergrowth impurities are difficult to remove by conventional beneficiation methods such as gravity separation, color separation, magnetic separation and flotation, and are a key factor affecting the quality of low-quality quartz. At present, acid leaching is often used to remove intergrowth in quartz, but it will pollute the environment and the cost is high. Therefore, it is of great practical significance to develop a low-intensity grinding method for deep purification of quartz sand, which removes the intergrowth impurities of quartz by low-intensity grinding of the concentrate after conventional beneficiation, and at the same time minimizes the overgrinding of quartz sand to ensure the yield of coarse particle size quartz sand. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for deep purification of quartz sand.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A method for deep purification of quartz sand, comprising the following steps:

[0009] (1) first, grinding the quartz coarse particles to obtain a sample with a particle size of -0.6+0.1 mm, and then performing magnetic separation to obtain a magnetic separation concentrate;

[0010] (2) removing gangue minerals from the magnetic separation concentrate of step (1) by multiple reverse flotation to obtain a flotation concentrate;

[0011] (3) grinding the flotation concentrate, the grinding speed being 50-250 r / min, the grinding time being 5-90 min, and the grinding concentration being 50-70%, and after the grinding treatment, screening the sample to take the -0.6+0.1 mm fraction as a grinding concentrate and the -0.1 mm fraction as a tailing, thereby completing the deep purification of the quartz sand.

[0012] Preferably, the gangue minerals of step (2) are at least one of mica, fluorite and feldspar.

[0013] Preferably, the reverse flotation of step (2) is performed in the following manner: using sulfuric acid as a pH regulator and dodecylamine as a collector to remove mica and fluorite impurities by three times of reverse flotation at a pH of 2.0-3.0; and using sulfuric acid as a pH regulator and a mixture of anionic and cationic collectors as a mixed collector to remove feldspar and iron-containing impurities by three times of reverse flotation at a pH of 1.5-2.0, thereby obtaining a flotation concentrate.

[0014] Preferably, the mixed collector is added in an amount of 900-1800 g / t.

[0015] Preferably, the ratio of the anion to the cation in the anionic and cationic collectors is 1:1-7:1.

[0016] Preferably, the cationic collector is at least one of dodecylamine, octadecylamine and coconut amine, and the anionic collector is at least one of petroleum sulfonate sodium, dodecyl sulfonate sodium and sodium oleate; more preferably, the cationic collector is dodecylamine and the anionic collector is petroleum sulfonate sodium.

[0017] Preferably, when removing mica and fluorite impurities, the dodecylamine is added in an amount of 50-300 g / t.

[0018] Preferably, the magnetic separation of step (2) is performed under the following conditions: a magnetic field strength of 1.0-1.8 T, a pulse frequency of 50-200 r / min and a flow rate of 1.0-2.0 cm / s.

[0019] Preferably, the grinding speed in step (3) is 50-100 r / min. The grinding speed is a crucial parameter in the grinding process. If the grinding speed is too high, the quartz will be broken indiscriminately, losing selectivity. If the grinding speed is too low, the gangue minerals will be difficult to be ground off. Therefore, it is necessary to explore the appropriate grinding speed.

[0020] Preferably, the grinding time in step (3) is 30-90 min. The grinding time is crucial in the grinding process. Under appropriate conditions, if the grinding time is too long, over-grinding will occur. If the grinding time is too short, it will be difficult to achieve good grinding effect.

[0021] Preferably, the grinding concentration in step (3) is 65%. Under appropriate conditions, if the grinding concentration is too low, the mineral particles will not be fully polished. If the grinding concentration is too high, over-grinding will occur.

[0022] Preferably, the grinding medium in step (3) is at least one of zirconium balls and steel balls.

[0023] Preferably, the diameter of the zirconium balls and steel balls is 1-10 mm.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] (1) Low-intensity grinding (grinding speed: 50-250 r / min, grinding time: 5-90 min, grinding concentration: 50-70%) can effectively remove the un-dissociated gangue mineral intergrowth in the quartz sand that does not meet the standard after conventional beneficiation, thereby improving the grade of quartz.

[0026] (2) The over-grinding of quartz sand is minimized, ensuring the yield of coarse-grained quartz sand products.

[0027] (3) Compared with the prior art, the method has the characteristics of clean and pollution-free, high efficiency, and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a flowchart of the method for deep purification of quartz sand according to the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0030] The cationic collector is dodecylamine (purchased from China National Pharmaceutical Group Corporation) and the anionic collector is petroleum sulfonate sodium (purchased from PetroChina Karamay Petrochemical Co., Ltd.).

[0031] The ball milling ratio in the examples and comparative examples is 3:1.

[0032] Example 1

[0033] A method for deeply purifying quartz sand, comprising the following steps:

[0034] The raw material is low-quality quartz from a certain place in Fujian, wherein the content of SiO2 is 96.52%, the content of Al2O3 is 1.5%, and the content of Fe2O3 is 0.17%.

[0035] (1) Milling: the crushed sample is milled to obtain a sample with a particle size of-0.6 mm+0.1 mm.

[0036] (2) Magnetic separation: the quartz is subjected to magnetic separation by using a magnetic separator to remove part of the magnetic impurities, and the magnetic field strength is 1.4 T to obtain a magnetic separation concentrate.

[0037] (3) Flotation: under the condition that the pH is 2.0-3.0, the mica and fluorite impurities are removed by reverse flotation three times by using sulfuric acid as a pH regulator and dodecylamine as a collector (the addition amount of dodecylamine is 150 g / t). Then, under the condition that the pH is 1.5-2.0, the feldspar and iron-containing impurities are removed by reverse flotation three times by adding an anion-cation mixed collector (the addition amount of the anion-cation mixed collector is 1500 g / t) and using sulfuric acid as a pH regulator to obtain a flotation concentrate, and the Al2O3 content is 2255 μg / g and the Fe2O3 content is 96.18 μg / g by ICP detection.

[0038] (4) The flotation concentrate is subjected to low-intensity milling under the conditions that the milling speed is 50 r / min, the milling time is 90 min, the milling concentration is 65%, and the milling medium is a zirconium ball with a diameter of 5 mm, and then the milling is screened.

[0039] (5) After screening, the-0.6 mm+0.1 mm particle size fraction is taken as a concentrate, and the sample is dried and prepared. The Al2O3 content is 932.78 μg / g and the Fe2O3 content is 68.83 μg / g by ICP detection.

[0040] Example 2

[0041] A method for deeply purifying quartz sand, comprising the following steps:

[0042] (1)-(3) are the same as in Example 1.

[0043] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 100 r / min, a grinding time of 60 min, and a grinding concentration of 65%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0044] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 821.24 μg / g, and the Fe2O3 content is 64.25 μg / g.

[0045] Example 3

[0046] A method for deeply purifying quartz sand, comprising the following steps:

[0047] (1)-(3) are the same as in Example 1.

[0048] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 150 r / min, a grinding time of 30 min, and a grinding concentration of 65%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0049] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 881.69 μg / g, and the Fe2O3 content is 74.17 μg / g.

[0050] Example 4

[0051] A method for deeply purifying quartz sand, comprising the following steps:

[0052] (1)-(3) are the same as in Example 1.

[0053] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 200 r / min, a grinding time of 20 min, and a grinding concentration of 65%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0054] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 967.18 μg / g, and the Fe2O3 content is 79.64 μg / g.

[0055] Example 5

[0056] A method for deeply purifying quartz sand, comprising the following steps:

[0057] (1)-(3) are the same as in Example 1.

[0058] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 250 r / min, a grinding time of 10 min, and a grinding concentration of 65%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0059] (5) After screening, the -0.6 mm+0.1 mm fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1087.67 μg / g, and the Fe2O3 content is 87.39 μg / g.

[0060] Example 6

[0061] A method for deeply purifying quartz sand, comprising the following steps:

[0062] (1)-(3) are the same as in Example 1.

[0063] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 50 r / min, a grinding time of 90 min, and a grinding concentration of 55%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0064] (5) After screening, the -0.6 mm+0.1 mm fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1267.82 μg / g, and the Fe2O3 content is 92.31 μg / g.

[0065] Example 7

[0066] A method for deeply purifying quartz sand, comprising the following steps:

[0067] (1)-(3) are the same as in Example 1.

[0068] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 50 r / min, a grinding time of 90 min, and a grinding concentration of 60%, with zirconium balls with a diameter of 5 mm as the grinding medium. After grinding, the concentrate is screened;

[0069] (5) After screening, the -0.6 mm+0.1 mm fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1491.32 μg / g, and the Fe2O3 content is 97.36 μg / g.

[0070] Comparative Example 1

[0071] A method for purifying quartz sand, comprising the following steps:

[0072] (1)-(3) are the same as in Example 1.

[0073] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 30 r / min, a grinding time of 90 min, a grinding concentration of 65%, and a grinding medium of zirconium balls with a diameter of 5 mm. After grinding, the concentrate is screened;

[0074] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1987.57 μg / g and the Fe2O3 content is 85.37 μg / g.

[0075] Comparative Example 2

[0076] A method for purifying quartz sand, comprising the following steps:

[0077] (1)-(3) are the same as in Example 1.

[0078] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 200 r / min, a grinding time of 2 min, a grinding concentration of 65%, and a grinding medium of zirconium balls with a diameter of 5 mm. After grinding, the concentrate is screened;

[0079] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1893.58 μg / g and the Fe2O3 content is 86.18 μg / g.

[0080] Comparative Example 3

[0081] A method for purifying quartz sand, comprising the following steps:

[0082] (1)-(3) are the same as in Example 1.

[0083] (4) The flotation concentrate is subjected to low-intensity grinding at a grinding speed of 200 r / min, a grinding time of 30 min, a grinding concentration of 40%, and a grinding medium of zirconium balls with a diameter of 5 mm. After grinding, the concentrate is screened;

[0084] (5) After screening, the -0.6 mm+0.1 mm size fraction is taken as the concentrate, which is dried and prepared into a sample. ICP detection shows that the Al2O3 content is 1633.75 μg / g and the Fe2O3 content is 78.94 μg / g.

[0085] The results of the detection of the quartz concentrate obtained by purification in Examples 1-7 and Comparative Examples 1-3 are shown in Table 1.

[0086] Table 1: Detection results of the concentrate in Examples 1-7 and Comparative Examples 1-3

[0087]

[0088]

[0089] The yield in Table 1 is calculated using the following formula: γ = m1 / m2 × 100%, where m1 is the mass of minerals in the -0.6mm +0.1mm particle size fraction after grinding, in g; m2 is the mass of the feed, in g; and γ is the grinding yield.

[0090] As can be seen from Table 1, the quartz concentrate obtained by the purification method described in this invention not only meets the requirements of the concentrate for the particle size of quartz sand, but also achieves the effect of removing impurities and intergrowths, and the yield is also relatively high.

[0091] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method of deep purification of quartz sand, characterized in that, The method comprises the following steps: (1) first, the quartz coarse particles are ground to obtain a sample with a particle size of-0.6+0.1 mm, and then magnetic separation is performed to obtain a magnetic separation concentrate; (2) the magnetic separation concentrate of step (1) is subjected to multiple reverse flotation to remove gangue minerals to obtain a flotation concentrate; (3) the flotation concentrate is subjected to grinding treatment, the grinding speed is 50-100 r / min, the grinding time is 30-90 min, and the grinding concentration is 50-70%, after the grinding treatment, the sample is screened, the-0.6+0.1 mm particle size is taken as the grinding concentrate, and the-0.1 mm particle size is taken as the tailings, and the depth purification of the quartz sand is completed; the medium for the grinding treatment of step (3) is at least one of zirconium balls and steel balls; the diameter of the zirconium balls and the steel balls is 1-10 mm.

2. The method of purifying quartz sand according to claim 1, wherein The gangue minerals of step (2) are at least one of mica, fluorite and feldspar.

3. The method of purifying quartz sand according to claim 2, wherein The reverse flotation of step (2) is performed in the following manner: sulfuric acid is used as a pH regulator, dodecylamine is used as a collector, and three times of reverse flotation are performed at a pH of 2.0-3.0 to remove mica and fluorite impurities; sulfuric acid is used as a pH regulator, and a mixture of anionic and cationic collectors is used as a mixed collector, and three times of reverse flotation are performed at a pH of 1.5-2.0 to remove feldspar and iron-containing impurities to obtain a flotation concentrate.

4. The method of purifying quartz sand according to claim 3, wherein The addition amount of the mixed collector is 900-1800 g / t.

5. The method of purifying quartz sand according to claim 4, wherein In the mixed collector, the ratio of anions to cations is 1:1-7:1; The cationic collector is at least one of dodecylamine, octadecylamine and coconut amine, and the anionic collector is at least one of petroleum sulfonate sodium, dodecyl sulfonate sodium and sodium oleate.

6. The method of purifying quartz sand according to claim 3, wherein When removing mica and fluorite impurities, the addition amount of dodecylamine is 50-300 g / t.

7. The method of purifying quartz sand according to any one of claims 1 to 3, wherein The grinding concentration of step (3) is 65%.

8. The method for deep purification of quartz sand according to any one of claims 1 to 3, characterized by the fact that The magnetic separation conditions of step (2) are as follows: the magnetic field strength is 1.0-1.8 T, the pulse frequency is 50-200 r / min, and the flow rate is 1.0-2.0 cm / s.

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