A method of floatation removal of fluid inclusions from vein quartz sand

Abstract

This invention discloses a method for removing fluid inclusions from vein quartz sand by flotation. The method includes the following steps: crushing and grinding the vein quartz to produce quartz sand with a particle size of -0.2 to +0.106 mm, and drying it for later use; performing a first flotation on the dried quartz sand to remove mica, obtaining a primary concentrate; washing the primary concentrate multiple times and drying it for later use; taking the dried primary concentrate for a second flotation, adding at least one of calcium and magnesium salts and sodium oleate, maintaining the pH of the system at 8-11 during the flotation process; after the flotation is completed, collecting the flotation froth, removing the froth, and obtaining quartz sand with fluid inclusions removed. This invention, through the control of flotation reagents, selects quartz particles containing a large number of fluid inclusions as gangue minerals, thereby changing the quartz particles in the quartz concentrate and reducing the fluid inclusion content in the concentrate to a greater extent.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing, and particularly relates to a method for removing fluid inclusions from vein quartz sand by flotation. Background Technology

[0002] High-purity quartz is widely used in industries such as photovoltaics, electronic information, optical communication, and electric light sources, and has huge demand in emerging industries such as energy conservation and environmental protection, next-generation information technology, new energy, and new materials. Vein quartz, as a potential high-purity quartz raw material, has been extensively studied. Vein quartz contains relatively little gangue minerals, generally only mica. Many domestic experts and scholars have conducted extensive research on the removal of gangue minerals and the improvement of chemical composition, including methods such as classification and sorting, alkaline leaching purification, and acid leaching purification, all of which have achieved good progress and breakthroughs. Furthermore, fluid inclusions exist in quartz crystals in various forms, and the content of inclusions varies significantly among different types and origins of quartz.

[0003] The presence of trace impurity elements in fluid inclusions is an inherent condition for evaluating whether quartz raw materials can be used to prepare high-purity quartz. For example, in the process of fused silica glass, the hydroxyl groups contained in the gas-liquid inclusions in the raw material are mainly composed of water molecules and hydroxyl water (OH-). - It is formed by the reaction of ions with SiO2, which will produce defects such as bubbles and gas lines. In addition, some water in the inclusions will dissolve in the quartz glass to form residual hydroxyl groups, which will cause changes in the physicochemical properties of high-purity quartz sand products.

[0004] Currently, the content of impurity elements in high-purity quartz is relatively easy to control, but the content of fluid inclusions is extremely difficult to control, generally depending on the level of fluid inclusions in the raw ore. Although fluid inclusions in quartz ore can be removed using methods such as high-temperature bursting, high-temperature vacuum, differential corrosion, and microwave methods, these methods are energy-intensive, effectively removing larger fluid inclusions, achieving only trace removal for micron-sized fluid inclusions, and even worse for submicron-sized fluid inclusions. Currently, many high-purity quartz sands on the market pass elemental testing but cannot be supplied to downstream users. This is essentially because the fluid inclusion content in the quartz sand is too high, leading to a large number of bubbles during processing and preventing the formation of a good transparent layer. Therefore, a new method should be invented that is energy-efficient and effectively removes tiny gas-liquid inclusions from high-quality quartz. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for removing fluid inclusions from vein quartz sand by flotation.

[0006] The dosage of reagents and flotation conditions such as pH used in this invention are stringent. Generally, the flotation of quartz only occurs in the separation of low-purity quartz from feldspar and quartz from other metallic minerals. There has been no research on using flotation reagents in the flotation separation of only quartz. This invention uses conventional positive flotation reagents for quartz and feldspar, but the dosage and pH conditions are quite different from those used in the separation of quartz and feldspar.

[0007] This invention employs flotation to remove quartz particles containing fluid inclusions. In flotation, it is often found that the floatability of the same mineral can vary significantly. This is because actual minerals are rarely ideal, typical pure minerals; they exhibit numerous physical and chemical inhomogeneities, resulting in surface inhomogeneities that cause various variations in floatability. Mineral surface inhomogeneities are the result of multiple factors, primarily physical and chemical. Actual mineral surfaces often contain minute voids and cracks. Different minerals exhibit varying amounts of internal voids and cracks, leading to significant differences in their specific surface area.

[0008] The particle size range used in this invention is within the required range for high-purity quartz sand, but it is further narrowed. This is because the surface properties of quartz with different contents of gas-liquid inclusions vary after crushing and grinding. After crushing and dissociation, the mineral surface has residual unsaturated bond energy due to the destruction of crystals, thus possessing a certain "surface energy." Unsaturated bonds have the characteristic of attracting surrounding substances to satisfy or compensate for their surface unsaturated bond energy. Depending on their properties and strength, they have a decisive influence on the adsorption of water, flotation reagents, air bubbles, and ions and molecules in water by the mineral surface. In this invention, quartz particles containing a large number of fluid inclusions will have these fluid inclusions broken during crushing and grinding, increasing the fracture surface of the quartz and its specific surface area, making it easier to adsorb reagents.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for removing fluid inclusions from vein quartz sand by flotation includes the following steps:

[0011] (1) The vein quartz was crushed and ground to produce quartz sand with a particle size of -0.2 to +0.106 mm, and then dried for later use;

[0012] (2) After removing mica by flotation, the dried quartz sand is given a primary concentrate. The primary concentrate is washed multiple times and then dried for later use.

[0013] (3) Take the dried primary concentrate for secondary flotation, add at least one of calcium salt and magnesium salt and sodium oleate, and maintain the pH of the system at 8~11 during the flotation process. After the flotation is completed, take the flotation foam, remove the foam, and obtain quartz sand with fluid inclusions removed. The purpose of secondary flotation is to make the quartz sand with less fluid inclusions float to the surface, and then the quartz sand with more fluid inclusions remain in the tank.

[0014] Preferably, the method for removing mica by flotation in step (2) is as follows: dodecylamine is used as the flotation reagent, with an addition amount of 80~150g / t, and the pH of the system is maintained at 2~3 during the flotation process.

[0015] Preferably, the washing method in step (2) is: washing with deionized water.

[0016] Preferably, the drying temperature in step (2) is 90~100℃.

[0017] Preferably, the calcium salt in step (3) is at least one of calcium chloride and calcium nitrate.

[0018] Preferably, the amount of at least one of the calcium salt and magnesium salt added in step (3) is 20~60g / t.

[0019] Preferably, the magnesium salt in step (3) is at least one of magnesium chloride, magnesium nitrate and magnesium sulfate.

[0020] Preferably, the amount of sodium oleate added in step (3) is 300~1000g / t.

[0021] Preferably, the amount of sodium oleate added in step (3) is 600~1000g / t.

[0022] Preferably, the pH of the system is maintained at 9~11 during the flotation process described in step (2).

[0023] Compared with the prior art, the beneficial effects of the present invention include:

[0024] Compared with other methods for removing fluid inclusions, such as thermal detonation, microwave-assisted heating detonation, and differential corrosion, this invention is more direct and effective. By controlling the flotation reagents, quartz particles containing a large number of fluid inclusions are selected as gangue minerals, thereby changing the quartz particles in the quartz concentrate and reducing the fluid inclusion content in the concentrate to a greater extent. Attached Figure Description

[0025] Figure 1 The images shown are optical microscopic images of the vein quartz ore described in Example 1, with the scale bar in the images being 250 μm.

[0026] Figure 2The images shown are optical microscope images of the foamed quartz sand described in Example 1, where the scale bar in the images is 250 μm.

[0027] Figure 3 The images shown are optical microscope images of the quartz sand in the tank described in Example 1, with the scale bar in the images being 250 μm.

[0028] Figure 4 The images shown are optical microscopic images of the vein quartz ore described in Example 2, with the scale bar in the images being 250 μm.

[0029] Figure 5 The images shown are optical microscope images of the foamed quartz sand described in Example 2, where the scale bar in the images is 250 μm.

[0030] Figure 6 The images shown are optical microscope images of the quartz sand in the tank described in Example 2, with the scale bar in the images being 250 μm.

[0031] Figure 7 The images shown are optical microscopic images of the vein quartz ore described in Example 3, with the scale bar in the images being 250 μm.

[0032] Figure 8 The images shown are optical microscopic images of the foamed quartz sand described in Example 3, where the scale bar in the images is 250 μm.

[0033] Figure 9 The images shown are optical microscope images of the quartz sand in the tank described in Example 3, with the scale bar in the image being 250 μm.

[0034] Figure 10 The images shown are optical microscopic images of the vein quartz ore described in Comparative Example 2, with the scale bar in the images being 250 μm.

[0035] Figure 11 The images shown are optical microscopic images of the foamed quartz sand described in Comparative Example 2, where the scale bar in the images is 250 μm.

[0036] Figure 12 This is a flowchart of the method for removing fluid inclusions from vein quartz sand by flotation according to the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] Example 1

[0039] A method for removing fluid inclusions from vein quartz sand by flotation, comprising the following steps:

[0040] (1) The quartz of a certain vein was crushed and ground to produce quartz sand with a particle size of -0.2 +0.106 mm, which was then dried for later use;

[0041] (2) The dried quartz sand is subjected to a first flotation to remove mica. The flotation reagent is dodecylamine, with a total dosage of 150 g / t. The pH is controlled between 2 and 3. After the flotation is completed, the tank contains the primary concentrate after removing mica. The primary concentrate is washed multiple times and then dried for later use.

[0042] (3) Take the dried primary concentrate for secondary flotation. First, add magnesium chloride at a rate of 40 g / t, then add sodium oleate at a rate of 800 g / t. Maintain the pH of the system at 11 during the flotation process. After the flotation is completed, take the flotation foam and remove the foam to obtain quartz sand with fluid inclusions removed.

[0043] The froth quartz sand after secondary flotation and the quartz sand in the tank were washed, filtered, and dried respectively. Samples of the raw ore, the froth quartz sand after secondary flotation, and the quartz sand in the tank were taken uniformly and observed under a microscope. The microscopic results are shown in the figure. Figures 1-3 .

[0044] Figure 1 This is an optical microscope image of the vein quartz ore described in Example 1. Figure 2 This is an optical microscope image of the foamed quartz sand described in Example 1. Figure 3 This is an optical microscope image of the quartz sand in the tank described in Example 1.

[0045] See Figures 1-3 It can be seen that flotation can remove quartz particles containing fluid inclusions from the raw ore, significantly reducing the proportion of particles containing fluid inclusions. Statistical analysis of 500 particles revealed that quartz particles containing fluid inclusions accounted for 45% of the raw ore, while only 23% of the flotation froth product and 68% of the particles in the flotation cell.

[0046] Example 2

[0047] A method for removing fluid inclusions from vein quartz sand by flotation, comprising the following steps:

[0048] (1) The quartz of a certain vein was crushed and ground to produce quartz sand with a particle size of -0.2 +0.106 mm, which was then dried for later use;

[0049] (2) The dried quartz sand is subjected to a first flotation to remove mica. The flotation reagent is dodecylamine, with a total dosage of 150 g / t. The pH is controlled between 2 and 3. After the flotation is completed, the tank contains the primary concentrate after removing mica. The primary concentrate is washed multiple times and then dried for later use.

[0050] (3) Take the dried primary concentrate for secondary flotation. First, add magnesium chloride at a rate of 50 g / t, then add sodium oleate at a rate of 600 g / t. During the flotation process, maintain the pH of the system at 10. After the flotation is completed, take the flotation foam and remove the foam to obtain quartz sand with fluid inclusions removed.

[0051] The froth quartz sand after secondary flotation and the quartz sand in the tank were washed, filtered, and dried respectively. Samples of the raw ore, the froth quartz sand after secondary flotation, and the quartz sand in the tank were taken uniformly and observed under a microscope. The microscopic results are shown in the figure. Figures 4-6 .

[0052] Figure 4 This is an optical microscope image of the vein quartz ore described in Example 2. Figure 5 This is an optical microscope image of the foamed quartz sand described in Example 2. Figure 6 This is an optical microscope image of the quartz sand in the tank described in Example 2.

[0053] See Figures 4-6 It can be seen that flotation can remove quartz particles containing fluid inclusions from the raw ore, significantly reducing the proportion of particles containing fluid inclusions. Statistical analysis of 500 particles revealed that 54% of the raw ore contained quartz particles with fluid inclusions, while only 37% were found in the flotation froth product, and 63% were found in the flotation cell.

[0054] Example 3

[0055] A method for removing fluid inclusions from vein quartz sand by flotation, comprising the following steps:

[0056] (1) The quartz of a certain vein was crushed and ground to produce quartz sand with a particle size of -0.2 +0.106 mm, which was then dried for later use;

[0057] (2) The dried quartz sand is subjected to a first flotation to remove mica. The flotation reagent is dodecylamine, with a total dosage of 150 g / t. The pH is controlled between 2 and 3. After the flotation is completed, the tank contains the primary concentrate after removing mica. The primary concentrate is washed multiple times and then dried for later use.

[0058] (3) Take the dried primary concentrate for secondary flotation. First, add calcium chloride at a rate of 60 g / t, then add sodium oleate at a rate of 1000 g / t. Maintain the pH of the system at 9 during the flotation process. After the flotation is completed, take the flotation foam and remove the foam to obtain quartz sand with fluid inclusions removed.

[0059] The froth quartz sand after secondary flotation and the quartz sand in the tank were washed, filtered, and dried respectively. Samples of the raw ore, the froth quartz sand after secondary flotation, and the quartz sand in the tank were taken uniformly and observed under a microscope. The microscopic results are shown in the figure. Figures 7-9 .

[0060] Figure 7 This is an optical microscope image of the vein quartz ore described in Example 3. Figure 8 This is an optical microscope image of the foamed quartz sand described in Example 3. Figure 9 This is an optical microscope image of the quartz sand in the tank described in Example 3.

[0061] See Figures 7-9 It can be seen that flotation can remove quartz particles containing fluid inclusions from the raw ore, significantly reducing the proportion of particles containing fluid inclusions. Statistical analysis of 500 particles revealed that 58% of the raw ore contained quartz particles with fluid inclusions, while only 35% were found in the flotation froth product, and 70% were found in the flotation cell.

[0062] Comparative Example 1

[0063] Based on Example 1, sodium oleate was not added during the second flotation, and the other steps were the same as in Example 1.

[0064] In Comparative Example 1, the quartz produced by secondary flotation could not float, indicating the absence of flotation foam quartz.

[0065] Comparative Example 2

[0066] Based on Example 2, the amount of sodium oleate used in the second flotation was adjusted to 1200 g / t, and the other steps were the same as in Example 2.

[0067] The froth quartz and quartz sand from the secondary flotation process described in Comparative Example 2 were washed, filtered, and dried, respectively. Samples of the raw ore, the froth quartz sand from the secondary flotation process, and the quartz sand from the quartz sand were taken uniformly and observed under a microscope. The microscopic results are shown in [Figure 1]. Figures 10-11 See also Figures 10-11 As can be seen, almost all of the quartz floats to the surface. Flotation cannot remove the quartz particles encased in fluid, and the flotation foam is no different from the original ore and the quartz in the tank.

[0068] Comparative Example 3

[0069] Based on Example 3, calcium chloride was not added during the second flotation, and the other steps were the same as in Example 3.

[0070] In Comparative Example 3, the quartz produced by secondary flotation could not float, indicating the absence of flotation foam quartz.

[0071] The statistical results of flotation of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0072] Table 1. Summary of Flotation Results for Examples and Comparative Examples

[0073]

[0074] As shown in Table 1, the type and amount of flotation reagents have a significant impact on the flotation results during secondary flotation and need to be strictly controlled.

[0075] 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 floatation removal of fluid inclusions from vein quartz sand, characterized in that, It comprises the following steps: (1) crushing and grinding the vein quartz to make quartz sand with particle size of-0.2+0.106 mm, and drying for standby; (2) after removing mica by once flotation on the dried quartz sand, the once concentrate is obtained, and the once concentrate is washed for multiple times, and dried for standby; The way of removing mica by once flotation in step (2) is: using dodecylamine as the flotation reagent, the adding amount is 80~150g / t, and the system pH is kept at 2~3 during the flotation process; (3) taking the once concentrate after drying for secondary flotation, adding at least one of calcium salt and magnesium salt and sodium oleate, keeping the system pH at 8~11 during the flotation process, and after the flotation, taking the flotation froth, removing the froth, and obtaining the quartz sand with removed fluid inclusions; The adding amount of sodium oleate in step (3) is 300~1000g / t.

2. The method of claim 1, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The washing way in step (2) is: using deionized water for washing.

3. The method of claim 1, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The drying temperature in step (2) is 90~100℃.

4. The method of claim 1, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The calcium salt in step (3) is at least one of calcium chloride and calcium nitrate.

5. The method of claim 4, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The adding amount of at least one of calcium salt and magnesium salt in step (3) is 20~60g / t.

6. The method of claim 5, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The magnesium salt in step (3) is at least one of magnesium chloride, magnesium sulfate and magnesium nitrate.

7. The method of claim 1, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The adding amount of sodium oleate in step (3) is 600~1000g / t.

8. The method of claim 1, wherein the fluid inclusions are removed from the vein quartz sand by flotation. The system pH is kept at 9~11 during the flotation process in step (3).

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