A method for double grinding and dissociation of quartz sand

Abstract

The application discloses a double-grinding synergistic dissociation method of quartz sand. First, the quartz ore is classified into coarse-grained quartz crystal quartz ore and fine-grained quartz crystal quartz ore. For the coarse-grained quartz crystal quartz ore, a first low-intensity grinding treatment is adopted, and the purpose is to remove the intergrowth of quartz and gangue minerals and the surface impurities of the quartz sand, and then a second high-intensity grinding treatment is carried out to grind the quartz sand particles to a proper sand particle size range. For the fine-grained quartz crystal quartz ore, a first high-intensity grinding treatment is adopted, and the purpose is to grind the quartz sand particles to a proper sand particle size range, and then a second low-intensity grinding treatment is carried out to remove the surface impurities. The surface impurities can be better removed through the strong-weak alternating grinding mode, and after the magnetic separation-flotation purification, compared with the traditional grinding mode, the quartz sand concentrate has a higher grade and a lower impurity element content.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mineral purification, and particularly relates to a double-milling synergistic dissociation method for quartz sand. BACKGROUND

[0002] Natural quartz sand is a sand-shaped quartz mineral raw material with quartz as the main mineral component, which is formed by long-term weathering of mother rocks such as granite, quartzite, quartz sandstone and vein quartz in nature. Its associated minerals include feldspar, rock debris, mica, clay minerals, and heavy minerals such as zircon, tourmaline, ilmenite and hornblende. The scale of this type of deposit is generally large, and its main advantage is that it usually has good natural particle size, sphericity and roundness, and is an ideal raw material for processing cast quartz sand, 3D printing sand, colored quartz sand and oil fracturing proppant. However, natural quartz sand has many impurities, and often needs to be purified.

[0003] Quartz has strict requirements on particle size in different fields of application, such as the glass industry, high-purity quartz and other fields, which usually require quartz sand to be in the particle size range of 0.1-0.6 mm. In the purification process of quartz, grinding mainly dissociates quartz and gangue minerals and achieves the corresponding separation particle size range. Commonly used for quartz grinding include ball mill, rod mill, autogenous mill, etc., which can reduce impurity content to a certain extent and obtain qualified particle size products, but cannot completely remove impurities and intergrowths on the surface of quartz sand.

[0004] With the extensive use of quartz resources, high-quality quartz resources are gradually depleted, and efficient use of low-quality quartz is gradually valued. Low-quality quartz often occurs with gangue minerals, such as using traditional grinding methods to fully dissociate quartz and gangue minerals, which results in a significant reduction in the yield of available quartz sand due to over-fine grinding. In order to ensure the relatively coarse particle size requirement of quartz sand application, it is impossible to fully dissociate quartz and gangue minerals, and due to the limitation of particle size, quartz and gangue minerals cannot be fully dissociated, which is the problem of low-quality quartz that cannot be efficiently utilized.

[0005] Therefore, it is of great practical significance to develop a double-milling synergistic grinding method for deep purification of quartz sand of different particle sizes, which uses a strong-weak alternating grinding method to efficiently remove impurities of quartz sand with different embedding characteristics. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a double-milling synergistic dissociation method for quartz sand, which uses double-milling synergistic crushing to solve the problems raised in the background art.

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

[0008] A double-grinding and dissociation method of quartz sand, comprising the following steps:

[0009] (1) Classify the quartz ore into coarse-grained quartz crystal quartz ore and fine-grained quartz crystal quartz ore; the crystal size of the coarse-grained quartz crystal quartz ore is -1.5+0.6 mm; the crystal size of the fine-grained quartz crystal quartz ore is -0.6+0.1 mm; in actual operation, when classifying the quartz ore, the ore is subjected to professional process mineralogy analysis, and the quartz sand crystal is observed by using a polarizing microscope for classification.

[0010] (2) Subject the coarse-grained quartz crystal quartz ore to primary grinding treatment, wherein the grinding mill speed is 50-100 r / min, and the grinding treatment time is 10-20 min; then subject to secondary grinding treatment, wherein the grinding mill speed is 150-200 r / min, and the grinding treatment time is 1-3 min, to obtain quartz sand sample one;

[0011] Subject the fine-grained quartz crystal quartz ore to primary grinding treatment, wherein the grinding mill speed is 150-200 r / min, and the grinding treatment time is 1-3 min; then subject to secondary grinding treatment, wherein the grinding mill speed is 50-100 r / min, and the grinding treatment time is 10-20 min, to obtain quartz sand sample two;

[0012] (3) Subject the quartz sand sample one and the quartz sand sample two to magnetic separation and flotation for impurity removal, respectively, to obtain quartz concentrate.

[0013] Preferably, in step (2), the primary grinding treatment of the coarse-grained quartz crystal quartz ore is performed at a grinding concentration of 70-80%.

[0014] Preferably, in step (2), the primary grinding treatment of the coarse-grained quartz crystal quartz ore is performed by using alumina balls as the grinding medium, wherein the diameter of the alumina balls is 1.3 cm, and the ball-to-ore ratio is 1.5:1.

[0015] Preferably, in step (2), the secondary grinding treatment of the coarse-grained quartz crystal quartz ore is performed at a grinding concentration of 50-60%.

[0016] Preferably, in step (2), the secondary grinding treatment of the coarse-grained quartz crystal quartz ore is performed by using alumina balls as the grinding medium, wherein the alumina balls include large balls with a diameter of 2.0 cm and small balls with a diameter of 1.3 cm, the large balls to small balls ratio is 3:1, and the ball-to-ore ratio is 2.5:1.

[0017] Preferably, in step (2), the primary grinding treatment of the fine-grained quartz crystal quartz ore is performed at a grinding concentration of 50-60%.

[0018] Preferably, in step (2), the fine quartz crystal quartz ore is subjected to one grinding treatment, and the grinding medium is alumina ball, the alumina ball has large ball with diameter of 2.0 cm and small ball with diameter of 1.3 cm, the large ball: small ball = 3:1, and the ball-to-material ratio is 2.5:1.

[0019] Preferably, in step (2), the fine quartz crystal quartz ore is subjected to one grinding treatment, and the grinding medium is alumina ball, the alumina ball has large ball with diameter of 2.0 cm and small ball with diameter of 1.3 cm, the large ball: small ball = 3:1, and the ball-to-material ratio is 2.5:1.

[0020] Preferably, in step (2), the fine quartz crystal quartz ore is subjected to one grinding treatment, and the grinding medium is alumina ball, the alumina ball has large ball with diameter of 2.0 cm and small ball with diameter of 1.3 cm, the large ball: small ball = 3:1, and the ball-to-material ratio is 2.5:1.

[0021] Preferably, in step (3), the magnetic separation is carried out under the conditions of magnetic field strength of 1.4 T, pulse frequency of 200 r / min, and flow rate of 2.0 cm / s.

[0022] The mechanism involved in the present application is as follows:

[0023] Grinding is the primary process of quartz sand purification processing, which has an important influence on the subsequent process. If a high-selectivity grinding method is used to efficiently remove the thin film on the surface of quartz, the removal effect of the subsequent purification process will be significantly improved. Secondly, during grinding, if the quartz particles can be opened along the gap between the grains, the vein minerals and inclusions between the gaps will be monomer cleavage or exposed on the surface of quartz, which will significantly improve the removal effect of the subsequent purification process.

[0024] Ball mill is the most commonly used grinding equipment in the current quartz sand processing and purification process. Ball milling can maximize the sphericity and roundness of quartz sand particles, and can reduce the quartz sand particles to qualified particle size in the shortest time.

[0025] The present application uses a ball mill as a grinding equipment. In the two-stage grinding process of quartz sand, a lower grinding intensity is used in the first stage, a higher grinding intensity is used in the second stage, and a weak-strong-weak alternating quartz sand grinding technology is used in different grinding stages. This can effectively reduce the existence of impurity minerals and intergrowths on the surface of quartz sand, greatly improve the grinding efficiency of quartz sand, ensure the yield of qualified particle size of quartz sand, and provide high-quality quartz sand for subsequent processing.

[0026] The application adopts one-stage low-intensity grinding and one-stage high-intensity grinding technology. According to the characteristics of the surface impurities of the quartz sand, the parameters such as the rotating speed of the grinding equipment, the type and size of the medium are controlled, the particle size damage of the quartz sand is small under high concentration and low intensity, and the dissociation of the quartz sand and the surface impurities can be better realized, and the quartz sand is ground to the qualified particle size range required by the subsequent process under the condition of low concentration and high intensity in the second stage, which can not only remove the surface impurities and the intergrowth to a certain extent, but also improve the grinding efficiency of the quartz sand.

[0027] The application adopts a strong-weak alternating regrinding process. According to the characteristics of the intergrowth generated in the quartz coarse concentrate in different stages of the quartz sand beneficiation process, the strong-weak alternating regrinding process of the quartz sand is adopted to solve the dissociation problem of the intergrowth with different particle sizes, different shapes and different embedding relationships in different stages, and the surface impurity minerals and the intergrowth are removed to the maximum extent. The whole process can improve the concentrate index of the quartz sand, especially the reduction of iron and aluminum elements.

[0028] The more the surface impurities and the intergrowth content in the quartz sand, the worse the flotation effect, and the subsequent acid leaching process is required to reduce the impurity element content to a relatively low level. Therefore, according to the different impurity element content of the quartz sand, the grinding intensity also adopts different combination forms.

[0029] Research shows that the general grinding process is a closed-circuit grinding process, the grinding concentration is controlled between 60-70%, and the rotating speed of the grinding machine is controlled at about 150r / min. The qualified particle size yield of the quartz sand in this process is between 70-80%, and the surface impurities and edge intergrowth of the quartz particles in the concentrate obtained by flotation cannot be completely removed, and the impurity element content of the concentrate is high. In order to separate the part of the intergrowth monomer, the grinding process is divided into two stages according to the different embedding characteristics of the quartz crystal and impurities, and different grinding methods are selected:

[0030] For coarse quartz crystals, the first stage is low-intensity high-concentration grinding, the rotating speed of the ball mill is controlled at 50-100r / min, the grinding concentration is 70-80%, the grinding time is 10-20min, the ball mill medium is alumina ball, and the particle size of the quartz sand basically does not change, but the intergrowth of the quartz and the gangue minerals and the surface impurities of the quartz sand are better removed. In the second grinding stage, the grinding intensity is appropriately increased and the grinding concentration is reduced. In the second regrinding process, the rotating speed of the ball mill is controlled at 150-200r / min, the grinding concentration is 50-60%, the grinding time is 1-3min, and the ball mill medium is alumina ball. The purpose is to regrind the quartz sand particles to the range of 0.1-0.6mm quartz sand particle size.

[0031] For fine-grained quartz crystal, the first section is high-strength low-concentration grinding, the rotation speed of the ball mill is controlled at 150-200 r / min, the grinding concentration is 50-60%, the grinding time is 1-3 min, the ball mill medium is alumina ball, and the purpose is to grind the quartz sand particles to 0.1-0.6 mm quartz sand particle size range; the second section is low-strength high-concentration grinding, the rotation speed of the ball mill is controlled at 50-100 r / min, the grinding concentration is 70-80%, the grinding time is 10-20 min, the ball mill medium is alumina ball, and the purpose is to remove surface impurities. After two-stage regrinding, there are basically no obvious impurity minerals and intergrowths on the surface and edges of the coarse-grained and fine-grained quartz flotation concentrates.

[0032] Compared with the prior art, the beneficial effects of the present application include:

[0033] The method can be applied to the purification of various coarse-grained and fine-grained quartz sands, and the surface impurities can be better removed through alternating strong and weak grinding. After magnetic separation and flotation purification, the quartz sand concentrate has higher grade and lower impurity element content compared with the traditional grinding method. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a coarse-grained quartz crystal inclusions and grinding treatment schematic diagram.

[0035] Figure 2 It is a fine-grained quartz crystal inclusions and grinding treatment schematic diagram.

[0036] Figure 3 It is a double-grinding synergistic dissociation method flowchart of the quartz sand. DETAILED DESCRIPTION

[0037] 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 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.

[0038] The anion-cation mixed collector in the examples and comparative examples has a cation to anion ratio of 2:1, wherein the cation is dodecylamine (purchased from Sinopharm Group Pharmaceutical Co., Ltd.) and the anion is sodium petroleum sulfonate, purchased from PetroChina Karamay Petrochemical Co., Ltd.

[0039] Example 1

[0040] A double-grinding synergistic dissociation method for quartz sand, the steps are as follows:

[0041] (1) The fine quartz sand ore in Longyan, Fujian is ground by double grinding and dissociation. The first grinding speed is controlled at 200 r / min, the grinding concentration is 55%, the grinding time is 3 min, the grinding medium is alumina ball, the ratio is 3:1 of 2.0 cm diameter large ball: 1.3 cm diameter small ball, and the ball-to-material ratio is 2.5:1. The second grinding speed is controlled at 75 r / min, the grinding concentration is 75%, the grinding time is 15 min, the grinding medium is alumina ball, the ball-to-material ratio is 1.5:1 of 1.3 cm diameter small ball, and after the second grinding, three-stage magnetic separation is performed. The magnetic separation conditions are as follows: the magnetic field strength is 1.4 T, the pulse frequency is 200 r / min, and the flow rate is 2.0 cm / s.

[0042] (2) After the magnetic separation, one-stage flotation of iron impurities is performed first. The reagent is sodium petroleum sulfonate, and the dosage is 3000 g / t. Then, three-stage flotation of mica is performed. The reagent is dodecylamine, the pH is 2-3, and the total dosage is 100 g / t. Then, three-stage flotation of feldspar is performed. The pH is 1.5-2, and the total dosage of mixed cationic and anionic collectors is 1500 g / t. Finally, the quartz concentrate is obtained.

[0043] The quartz concentrate is subjected to ICP detection. The iron oxide content is 150 μg / g, and the aluminum oxide content is 3000 μg / g.

[0044] Comparative Example 1

[0045] A method for purifying quartz sand, comprising the following steps:

[0046] The fine quartz sand ore in Longyan, Fujian is ground. The grinding concentration is 60%, the grinding time is 2.5 min of circulating grinding, the grinding speed is 150 r / min, the grinding medium is alumina ball, the ratio is 3:1 of 2.0 cm diameter large ball: 1.3 cm diameter small ball, and the ball-to-material ratio is 3:1. After grinding, magnetic separation and flotation are performed to obtain quartz concentrate. The operation steps of magnetic separation and flotation are the same as those in Example 1.

[0047] The obtained quartz concentrate is subjected to ICP detection.

[0048] Example 2

[0049] A method for purifying quartz sand, comprising the following steps:

[0050] (1) The coarse-grained quartz sand mine in Beihai area of Guangxi is ground by double grinding and collaborative dissociation. The first stage grinding speed is controlled at 70 r / min, the grinding concentration is 80%, the grinding time is 15 min, the ball grinding medium is alumina ball with a diameter of 1.3 cm, and the ball-to-material ratio is 1.5:1. The second stage grinding speed is controlled at 180 r / min, the grinding concentration is 60%, the grinding time is 3 min, the ball grinding medium is alumina ball with a diameter of 2.0 cm, and the ball-to-material ratio is 2.5:1. After the second stage grinding, three stage magnetic separation is performed, and the magnetic separation conditions are as follows: the magnetic field strength is 1.4 T, the pulse frequency is 200 r / min, and the flow rate is 2.0 cm / s.

[0051] (2) After the magnetic separation, one stage of flotation of iron impurities is performed first, and the reagent is sodium petroleum sulfonate with a dosage of 2500 g / t. Then three stages of flotation of mica are performed, and the reagent is dodecylamine with a total dosage of 80 g / t at a pH of 2-3. Then three stages of flotation of feldspar are performed at a pH of 1.5-2 with a total dosage of 1200 g / t of mixed cationic and anionic collectors, to obtain quartz concentrate.

[0052] The quartz concentrate is subjected to ICP detection, and the content of iron oxide is 120 μg / g, and the content of aluminum oxide is 2000 μg / g.

[0053] Comparative Example 2

[0054] A method for purifying quartz sand, comprising the following steps:

[0055] The coarse-grained quartz sand mine in Beihai area of Guangxi is ground, and the grinding concentration is 65%, the grinding time is 2 min of circulating grinding, the grinding speed of the grinding machine is 140 r / min, the ball grinding medium is alumina ball with a diameter of 2.0 cm, and the ball-to-material ratio is 3:1. After grinding, magnetic separation and flotation are performed to obtain quartz concentrate, and the operation steps of magnetic separation and flotation are the same as those of Example 2.

[0056] The obtained quartz concentrate is subjected to ICP detection.

[0057] Example 3

[0058] A method for purifying quartz sand, comprising the following steps:

[0059] (1) The fine quartz sand ore in Yichun area of Jiangxi province is ground by double grinding and dissociation. The first stage grinding speed is controlled at 180 r / min, the grinding concentration is 50%, the grinding time is 3 min, the grinding medium is alumina ball, the ratio is 3:1 of 2.0 cm diameter big ball: 1.3 cm diameter small ball, and the ball-to-material ratio is 2.5:1. The second stage grinding speed is controlled at 90 r / min, the grinding concentration is 70%, the grinding time is 10 min, the grinding medium is alumina ball, the diameter of small ball is 1.3 cm, and the ball-to-material ratio is 1.5:1. After the second stage grinding, three stage magnetic separation is carried out. The magnetic field strength is 1.4 T, the pulse frequency is 200 r / min, and the flow rate is 2.0 cm / s.

[0060] (2) After the magnetic separation, one stage of flotation of iron impurities is carried out first. The reagent is petroleum sulfonic acid sodium, and the dosage is 4000 g / t. Then three stages of flotation of mica are carried out. The reagent is dodecylamine, the pH is 2-3, and the total dosage is 150 g / t. Then three stages of flotation of feldspar are carried out. The pH is 1.5-2, and the total dosage of mixed cationic and anionic collectors is 1800 g / t. The quartz concentrate is obtained.

[0061] The quartz concentrate is subjected to ICP detection. The content of iron oxide is 180 μg / g, and the content of aluminum oxide is 3500 μg / g.

[0062] Comparative Example 3

[0063] A method for purifying quartz sand, comprising the following steps:

[0064] The fine quartz sand ore in Yichun area of Jiangxi province is ground. The grinding concentration is 60%, the grinding time is 3 min of circulating grinding, the grinding speed of the grinding machine is 150 r / min, the grinding medium is alumina ball, the ratio is 3:1 of 2.0 cm diameter big ball: 1.3 cm diameter small ball, and the ball-to-material ratio is 3:1. After the grinding, magnetic separation and flotation are carried out to obtain quartz concentrate. The operation steps of magnetic separation and flotation are the same as those in Example 3.

[0065] The obtained quartz concentrate is subjected to ICP detection.

[0066] The ICP detection results of the quartz concentrates prepared in Examples 1-3 and Comparative Examples 1-3 are statistically analyzed. The statistical results are shown in Table 1.

[0067] Table 1 Comparison of ICP detection results of quartz concentrates prepared in Examples 1-3 and Comparative Examples 1-3

[0068]

[0069] From the detection results of Table 1, it can be seen that the strong-weak alternating grinding mode can better remove surface impurities, and after magnetic separation-flotation purification, the quartz sand concentrate has higher grade and lower impurity element content compared with the traditional grinding mode.

[0070] The specific embodiments of the application described above do not constitute a limitation of the protection scope of the application. Any various other corresponding changes and modifications made according to the technical concept of the application shall be included in the protection scope of the claims of the application.

Claims

1. A dual-milling synergistic dissociation method for quartz sand, characterized in that, Includes the following steps: (1) Quartz minerals are classified into coarse-grained quartz crystal minerals and fine-grained quartz crystal minerals; the crystal size of coarse-grained quartz crystal minerals is -1.5 + 0.6 mm; the crystal size of fine-grained quartz crystal minerals is -0.6 + 0.1 mm. (2) The coarse-grained quartz crystal ore is subjected to a first grinding process, wherein the mill speed of the first grinding process is 50-100 r / min and the grinding time is 10-20 min; then a second grinding process is performed, wherein the mill speed of the second grinding process is 150-200 r / min and the grinding time is 1-3 min, to obtain quartz sand sample one. Fine-grained quartz crystal ore is subjected to a first grinding process at a mill speed of 150-200 r / min for 1-3 min; then a second grinding process is performed at a mill speed of 50-100 r / min for 10-20 min to obtain quartz sand sample two. (3) Magnetic separation and flotation were performed on quartz sand sample 1 and quartz sand sample 2 respectively to remove impurities, and quartz refined sand was obtained.

2. The dual-milling synergistic dissociation method for quartz sand according to claim 1, characterized in that, In step (2), the coarse-grained quartz crystal ore is subjected to a grinding process, and the grinding concentration of the grinding process is 70-80%.

3. The dual-milling synergistic dissociation method for quartz sand according to claim 2, characterized in that, In step (2), for coarse-grained quartz crystal ore, the grinding concentration of the secondary grinding process is 50-60%.

4. The dual-milling synergistic dissociation method for quartz sand according to any one of claims 2 to 3, characterized in that, In step (2), the coarse-grained quartz crystal ore is subjected to a grinding process. The grinding medium is alumina balls with a diameter of 1.3 cm and a ball-to-material ratio of 1.5:

1.

5. The dual-milling synergistic dissociation method for quartz sand according to claim 4, characterized in that, In step (2), for coarse-grained quartz crystal ore, the medium for the secondary grinding process is alumina balls. The alumina balls are large balls with a diameter of 2.0 cm and small balls with a diameter of 1.3 cm. The ratio of large balls to small balls is 3:1, and the ball-to-material ratio is 2.5:

1.

6. The dual-milling synergistic dissociation method for quartz sand according to claim 1, characterized in that, In step (2), the fine-grained quartz crystal ore is subjected to a grinding process, and the grinding concentration of the grinding process is 50-60%.

7. The dual-milling synergistic dissociation method for quartz sand according to claim 6, characterized in that, In step (2), for fine-grained quartz crystal ore, the grinding concentration of the secondary grinding process is 70-80%.

8. The dual-milling synergistic dissociation method for quartz sand according to any one of claims 6 to 7, characterized in that, In step (2), the fine-grained quartz crystal ore is subjected to a grinding process. The grinding medium is alumina balls, which are large balls with a diameter of 2.0 cm and small balls with a diameter of 1.3 cm. The ratio of large balls to small balls is 3:1, and the ball-to-material ratio is 2.5:

1.

9. The dual-milling synergistic dissociation method for quartz sand according to claim 8, characterized in that, In step (2), for fine-grained quartz crystal ore, the medium for the secondary grinding process is alumina balls with a diameter of 1.3 cm and a ball-to-material ratio of 1.5:

1.

10. The dual-milling synergistic dissociation method for quartz sand according to claim 1, characterized in that, The conditions for magnetic separation in step (3) are: magnetic field strength of 1.4T, pulse frequency of 200r / min, and flow velocity of 2.0cm / s.

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