Manufacturing process for synthesizing high-purity quartz sand by silicon tetrachloride liquid-phase hydrolysis method

Abstract

The invention discloses a manufacturing process for synthesizing high-purity quartz sand by a silicon tetrachloride liquid-phase hydrolysis method, which comprises the following process steps in sequence: carrying out liquid-phase hydrolysis on silicon tetrachloride and water, and then washing, carrying out solid-liquid separation, drying, calcining, grinding and screening the hydrolysis product to finally obtain high-purity quartz powder, a heating process is carried out while solid-liquid separation is carried out, or the heating process is carried out between the washing process and the solid-liquid separation process; or a heating process is carried out while the washing process is carried out. The orthosilicic acid in the hydrolysate is easier to decompose into metasilicic acid due to heating; in this way, metasilicic acid almost completely exists during solid-liquid separation, only filter residues of metasilicic acid particles exist on the filter screen and are easy to transfer, and the problem that colloidal precipitated orthosilicic acid filter residues are difficult to transfer is solved. Loss of orthosilicic acid is avoided as far as possible, raw material consumption is reduced, preparation cost is reduced, and the filter screen is convenient to clean.

Description

Technical Field

[0001] The invention relates to the preparation of finely dispersed silica in neither sol nor gel state; and its post-treatment, specifically to a manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride. Background Art

[0002] Using SiCl 4 Liquid phase hydrolysis method is used to prepare high purity quartz powder. Since the raw material does not contain carbon, the prepared SiO 2 The powder has high purity and low hydroxyl content. Xu Hua published a paper titled "Preparation of Silica Microspheres by Hydrolysis of Silicon Tetrachloride in Microemulsion" in Inorganic Salt Industry, Vol. 49, No. 12, December 2017, and Zhang Xiangjing published a paper titled "Study on the Process of Preparing Nano-Silica Powder by Hydrolysis of Silicon Tetrachloride" in Inorganic Salt Industry, Vol. 45, No. 10, October 2013. There are some studies on the preparation of small-particle silicon dioxide powder (whose particle size is nanometer-level and no longer belongs to quartz sand) from silicon tetrachloride in the existing technology, but there are few studies on the preparation of quartz sand by liquid phase hydrolysis of silicon tetrachloride. Patent with publication number CN114835130A: A method for producing high-purity quartz, wherein quartz sand and carbon-containing substances are ground into powder, dried and mixed to obtain a mixed raw material and chlorine gas, and then added to a high-temperature reactor for chlorination reaction to prepare silicon tetrachloride; the silicon tetrachloride collected by the cooling system is first removed from the boron, phosphorus, carbon-hydrogen bonds, hydrogen-oxygen bonds and other trace impurities through an adsorption device, and then separated and purified by multi-stage distillation of a light removal tower, a heavy removal tower, a light removal tower, a motorized tower, and a heavy removal tower to remove light and heavy component impurities in the silicon tetrachloride, and after the distillation is completed, trace solid particles and metal ion impurities are removed by membrane separation, and finally a liquid phase hydrolysis method is used to obtain high-purity quartz...Silicon tetrachloride is contacted with pure water to undergo liquid phase hydrolysis, and then the hydrolysis product is washed, solid-liquid separated, dried, calcined, ground and screened to finally obtain high-purity quartz powder. Its hydrolysis process is still SiCl 4 After contact with pure water, a hydrolysis reaction occurs. The reaction product undergoes washing, filtering, drying, calcining and screening to prepare SiO2 powder in a conventional process. The products of the hydrolysis of silicon tetrachloride and water in the liquid phase include not only hydrogen chloride, but also orthosilicic acid and metasilicic acid. Orthosilicic acid is generally in the form of a white colloidal precipitate, while metasilicic acid is an amorphous particle (colorless and transparent crystals, sometimes in the form of a white powder). If the reaction product is washed and filtered, there will be a colloidal residue on the filter in addition to solid residue. It is inconvenient to transfer the residue, and some of the orthosilicic acid will inevitably be lost, which increases the amount of raw materials used, increases the preparation cost, and is inconvenient to clean the filter. In addition, in the large-scale production process, the hydrolysis and polycondensation reactions of silicon tetrachloride and water are violent, the intermediate process is difficult to control, and the powder is easy to agglomerate. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects in the prior art and provide a manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride. The orthosilicic acid in the hydrolysis product is more easily decomposed into metasilicic acid due to heat; thus, when solid-liquid separation is performed, almost all of the product is metasilicic acid, and only the filter residue of metasilicic acid particles is left on the filter screen, which is easy to transfer, thereby avoiding the problem that the filter residue of colloidal precipitate of orthosilicic acid is difficult to transfer.

[0004] To achieve the above object, the technical solution of the present invention is to design a manufacturing process for synthesizing high-purity quartz sand by liquid-phase hydrolysis of silicon tetrachloride, which is composed of the following process steps performed in sequence: liquid-phase hydrolysis of silicon tetrachloride and water, and then washing, solid-liquid separation, drying, calcining, grinding and screening the hydrolyzate to finally obtain high-purity quartz powder; A heating process is provided at the same time as solid-liquid separation, or a heating process is provided between the washing process and the solid-liquid separation process; or a heating process is provided at the same time as the washing process. Alternatively, the heating process can also be incorporated into the washing process to further reduce the complexity of the process, such as washing with warm water at 40-55°C, so that the orthosilicic acid in the hydrolyzate is more easily decomposed into metasilicic acid due to heat; in this way, when solid-liquid separation is performed again, it is almost all metasilicic acid, and only the filter residue of metasilicic acid particles is on the filter screen, which is easy to transfer, avoiding the problem that the orthosilicic acid residue of colloidal precipitation is difficult to transfer.

[0005] A further technical solution is that the temperature of the drying process is 100-200°C, the filter residue is placed in a constant temperature box for dehydration and drying to constant weight and then transferred to a calcining furnace, and the calcining temperature of the calcining process is 1300-1500°C.

[0006] A further technical solution is that the heating process is to heat the filter residue on the filter screen involved in the solid-liquid separation process or to heat the washed product.

[0007] A further technical solution is that the calcining furnace for the calcining process consists of a furnace body, a furnace shell arranged outside the furnace body, a heating component arranged between the furnace shell and the furnace body, and a driving mechanism arranged outside the furnace body for driving the furnace body to rotate, the heating component includes a plurality of direct-fired heating ports arranged at intervals on the lower outer side of the furnace body; the length of the furnace shell is smaller than the furnace body; the driving mechanism is located near both ends of the furnace body in the length direction of the furnace body, the driving mechanism is located under the furnace body and outside the furnace shell, and the direct-fired heating port is located inside the furnace shell. A direct-combustion heating port is arranged on the lower outer side of the rotating furnace body, which happens to be opposite to the position where more materials accumulate in the furnace body (although the materials in the furnace cavity rotate with the furnace, the materials due to their own weight accumulate more in the middle and lower part of the furnace cavity inside the furnace body. In this way, the heating port for direct flame combustion heating is arranged on the lower outer side of the furnace body, which can ensure that more materials get more heating. In terms of the distribution of materials in the furnace cavity, such a setting of the heating port is also a perfect match, which can better ensure the uniformity of the calcination process, better control the particle size distribution of quartz sand, avoid the generation of excessively fine particles, and effectively avoid the agglomeration of quartz sand powder).

[0008] A further technical solution is that the driving mechanism includes a driving motor, a transmission connected to the driving motor, a gear fixedly arranged on the output shaft of the transmission, a gear meshing with the gear through a gear ring, the gear ring is fixedly connected to the outer wall of the furnace body, an annular belt is fixedly arranged on the outer wall of the furnace body, and a supporting wheel is arranged to match the belt. The driving motor is started to drive the transmission to rotate and then drive the gear to rotate, thereby driving the gear ring to rotate, thus driving the furnace body to rotate, realizing the function of rotary calcination, and combined with the setting of the furnace body tilting, calcination can be achieved while feeding.

[0009] A further technical solution is that the hydrolysis product is washed, solid-liquid separated, and dried before being delivered to the feed port on the furnace body of the calcining furnace, and the furnace body is heated by the direct-fired heating port. After the material enters the furnace body, it is transported simultaneously with the furnace body rotating with the inclined setting, and the material is discharged after reaching the discharge port. The two ends of the furnace body are respectively connected with the furnace head cover and the furnace tail box. The furnace body and the furnace head cover are sealed by the furnace head seal to ensure the sealing, and the furnace body and the furnace tail box are sealed by the furnace tail seal to ensure the sealing; the feed port is set on the furnace body cover, and the discharge port is set on the furnace tail box. A spirally distributed material guide strip is fixedly set at the position of the inner wall of the furnace body near the furnace head cover to make the material entering the furnace cavity of the furnace body as evenly distributed as possible (playing the role of lifting the material when the furnace body rotates) to avoid accumulation.

[0010] The advantages and beneficial effects of the present invention are that the orthosilicic acid in the hydrolysis product is more easily decomposed into metasilicic acid due to heat; thus, when the solid-liquid separation is performed, almost all of the residue is metasilicic acid, and only the residue of metasilicic acid particles is on the filter screen, which is easy to transfer, thereby avoiding the problem that the residue of colloidal precipitated orthosilicic acid is difficult to transfer. The loss of orthosilicic acid is avoided as much as possible, the amount of raw materials used is reduced, the preparation cost is reduced, and the filter screen is also easy to clean.

[0011] A direct-combustion heating port is arranged on the lower outer side of the rotating furnace body, which happens to be opposite to the position where more materials accumulate in the furnace body (although the materials in the furnace cavity rotate with the furnace, the materials due to their own weight accumulate more in the middle and lower part of the furnace cavity inside the furnace body. In this way, the heating port for direct flame combustion heating is arranged on the lower outer side of the furnace body, which can ensure that more materials get more heating. In terms of the distribution of materials in the furnace cavity, such a setting of the heating port is also a perfect match, which can better ensure the uniformity of the calcination process, better control the particle size distribution of quartz sand, avoid the generation of excessively fine particles, and effectively avoid the agglomeration of quartz sand powder).

[0012] By starting the drive motor to drive the transmission to rotate and then drive the gear to rotate, thereby driving the ring gear to rotate, thus driving the furnace body to rotate, realizing the effect of rotary calcination, and combined with the setting of the inclined furnace body, calcination and material feeding can be achieved at the same time.

[0013] The hydrolysis product is washed, solid-liquid separated and dried before being delivered to the feed port on the furnace body of the calcining furnace. The furnace body is heated by the direct-fired heating port. After entering the furnace body, the material is transported simultaneously with the furnace rotation and the inclined furnace body. The material is discharged after reaching the discharge port. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a calcining furnace in Example 1 of a manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to the present invention; Figure 2 yes Figure 1 The main view; Figure 3 yes Figure 2 A partial enlarged schematic diagram of Figure 4 yes Figure 2 AA section view; Figure 5 yes Figure 2 CC section view; Figure 6 is a schematic diagram of an example of a calcining furnace in Embodiment 2 of the present invention; Figure 7 is a schematic diagram of another example of the calcining furnace in the second embodiment of the present invention; Figure 8 is a schematic diagram of a solid-liquid separation device in Embodiment 3 of the present invention; Fig. 9 is a schematic diagram of a calcining furnace in Embodiment 4 of the present invention; Fig.10 yes Fig. 9 A schematic diagram from another perspective; Fig.11 is a schematic diagram of a calcining furnace in Embodiment 5 of the present invention; Fig.12 yes Fig.11 A schematic cross-sectional view of a longitudinal section of; Fig.13 yes Fig.11 Right view of; Fig.14 is a schematic diagram of a calcining furnace in Embodiment 6 of the present invention; Fig.15 yes Fig.14 Side view of Fig.16 yes Fig.14 Exploded diagram of the middle round rod, round tube and gear ring; Fig.17 yes Fig.16 Another working state diagram of .

[0015] In the figure: 1. furnace body; 2. furnace shell; 3. direct-fired heating port; 4. driving motor; 5. transmission; 6. gear; 7. gear ring; 8. wheel belt; 9. supporting wheel; 10. furnace head cover; 11. furnace tail box; 12. feeding port; 13. discharging port; 14. exhaust port; 15. material guide bar; 16. filter screen; 17. solid-liquid separation device; 18. metal ring; 19. plastic ring; 20. sub-furnace body; 21. dispersant addition port; 22. support seat; 23. second support seat; 24. arc-shaped long plate; 25. spring; 26. spring piece; 27. opening; 28. round rod; 29. ​​round tube; 30. elastic ring. DETAILED DESCRIPTION

[0016] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0017] Embodiment 1: Figures 1 to 5 As shown (for ease of illustration, Figure 1The furnace shell is not shown). The present invention is a manufacturing process for synthesizing high-purity quartz sand by liquid-phase hydrolysis of silicon tetrachloride. Silicon tetrachloride and water undergo liquid-phase hydrolysis, and then the hydrolysis product is subjected to washing, solid-liquid separation, drying, calcination, grinding and screening processes to finally obtain high-purity quartz powder. A heating process is also provided at the same time as the solid-liquid separation, or a heating process is provided between the washing process and the solid-liquid separation process; or a heating process is provided at the same time as the washing process. The temperature of the drying process is 100-200°C, the filter residue is placed in a constant temperature box for dehydration and drying to constant weight, and then transferred to a calcining furnace, and the calcining temperature of the calcining process is 1300-1500°C; the heating process is to heat the filter residue on the filter screen involved in the solid-liquid separation process (such as directly heating the filter screen or heating the filter container) or to heat the washed product (so that the original silica colloid in the solution is further decomposed into metasilicic acid, so that after heating and solid-liquid separation, there are only metasilicic acid particles on the filter screen, which is easy to transfer, avoiding the problem that the colloidal precipitated filter residue is difficult to transfer); the hydrolysis product is washed, solid-liquid separated, and dried, and then delivered to the feed port on the furnace body of the calcining furnace, and the furnace body is heated by the direct-fired heating port. After the material enters the furnace body, it is transported simultaneously with the furnace rotation and the inclined furnace body, and the material is discharged after reaching the discharge port.

[0018] The calcining furnace consists of a furnace body 1, a furnace shell 2 arranged outside the furnace body 1, a heating component arranged between the furnace shell and the furnace body, and a driving mechanism arranged outside the furnace body 1 for driving the furnace body to rotate, wherein the heating component includes a plurality of direct-fired heating ports 3 arranged at intervals on the outer side of the lower part of the furnace body; the length of the furnace shell 2 is smaller than the furnace body; the driving mechanism is located near the two ends of the furnace body in the length direction of the furnace body 1, the driving mechanism is located under the furnace body and outside the furnace shell 2, and the direct-fired heating port 3 is located inside the furnace shell; the driving mechanism includes a driving motor 4, a transmission 5 connected to the driving motor, a gear 6 is fixedly arranged on the output shaft of the transmission, and a gear ring 7 is engaged with the gear, and the gear ring is fixedly connected to the outer wall of the furnace body, and an annular wheel belt 8 is also fixedly arranged on the outer wall of the furnace body, and a supporting wheel 9 is arranged to match the wheel belt. The two ends of the furnace body 1 are respectively connected with a furnace head cover 10 and a furnace tail box 11. The furnace body and the furnace head cover are sealed by the furnace head seal, and the furnace body and the furnace tail box are sealed by the furnace tail seal. The feed port 12 is arranged on the furnace body cover 10, and the discharge port 13 is arranged on the furnace tail box 11. The furnace tail box is also provided with an exhaust port 14 arranged opposite to the discharge port. The inner wall of the furnace body 1 is fixedly provided with a spirally distributed material guide bar 15 near the furnace head cover 10 to make the material entering the furnace cavity of the furnace body as evenly distributed as possible (playing the role of lifting the material when the furnace body rotates) to avoid accumulation.

[0019] Embodiment 2: The difference from Embodiment 1 is that a plurality of spaced filters 16 are arranged in the furnace body 1 of the calcining furnace in the calcining process, and the mesh size of the filter screen increases along the calcining feeding direction; the filter screen adopts a ceramic filter screen, a stainless steel filter screen, or a silicon-based ceramic filter screen; the filter screen is located near the discharge port of the calcining furnace (and only one is arranged; in this way, the furnace shell 2 and the direct-fired heating port 3 arranged in the furnace body 1 are arranged closer to the feed port and farther away from the discharge port and the exhaust port 14, such as Figure 6 or the filter screen 16 is arranged at the feed inlet, the discharge outlet and the middle of the furnace body (as shown); Figure 7 As shown); filter screens are set up step by step in the furnace body of the calcining furnace (calcining rotary furnace) in the calcining process, so that the agglomerated powder material gathers on the filter screen, and is recovered step by step according to the particle size after shutdown (or only one filter screen is set up at the discharge port, so that when the discharge is significantly reduced, the filter screen is removed and the agglomerated powder on the filter screen is mechanically dispersed and deagglomerated), and then dispersed and deagglomerated by a jet mill; instead of considering how to prevent agglomeration during preparation in the past, the quartz sand is post-processed and deagglomerated after preparation, and the non-agglomerated quartz sand is collected and then the deagglomerated quartz sand is collected; this reduces the complexity of the preparation process and reduces or even eliminates the use of dispersants. In this way, the requirements for the calcining furnace can be reduced, and the technical transformation is relatively simpler, and only filters with different mesh sizes need to be set up at intervals in the furnace body.

[0020] Embodiment 3: The difference from Embodiment 1 is that Figure 8 As shown, the solid-liquid separation device 17 used in the solid-liquid separation process can use a solid-liquid separation cyclone, including a cylindrical device body, a filter screen is fixedly arranged in the device body, and the device body is formed by a metal ring 18 located at the filter screen and a plastic ring 19 located on both sides of the metal ring, which is fixedly sealed and connected. The outer wall of the metal ring is connected to the heating wire. After the heating wire is started, the heat is transferred to the metal filter screen fixed in the metal ring to complete the heating of the filter screen; in this way, the heating of the filter screen can be accurately heated, and there is no need to heat the entire solid-liquid separation device, reducing heat waste. It also solves the problem that the filter screen is difficult to heat during solid-liquid separation.

[0021] Embodiment 4: The difference from Embodiment 2 is that Fig. 9 , Fig.10 As shown (for ease of illustration, Fig. 9 Only part of the furnace shell, part of the dispersant dosing port, and part of the drive mechanism are shown; Fig.10The furnace shell and dispersant addition port are not shown; only one driving mechanism is shown). The furnace body 1 of the calcining furnace is tilted and divided. If the discharge amount of the discharge port 13 decreases, it means that the quartz sand powder is agglomerated and the filter screen 16 is blocked. (By observing the material transportation situation inside each sub-furnace body {that is, when the material of a certain section of the sub-furnace body hardly discharges from the filter screen at its lower end or there is obviously a lot of material accumulated on the filter screen at its lower end}, it can be clearly determined in which sub-furnace body the powder agglomeration occurs) and the powder agglomeration part (in the sub-furnace body where the powder agglomerates) is accelerated to rotate; dispersant is added between the two-stage filter screens 16 to cooperate with the mechanical accelerated rotation to deagglomerate, effectively control the agglomeration of quartz powder, reduce the amount of dispersant, and achieve effective addition of dispersant; the added dispersant can be polyethylene glycol, sodium dodecylbenzene sulfonate, etc.

[0022] The furnace body 1 is composed of several sub-furnace bodies connected by rotary seals, and a driving mechanism is arranged under each sub-furnace body to realize the rotation of each sub-furnace body; when the speed of a sub-furnace body 20 needs to be increased, the speed of the driving motor under it can be increased accordingly; the furnace shell is changed into several sections of sub-furnace shells, and there is a distance between each sub-furnace shell; a dispersant addition port 21 is arranged on each sub-furnace body; a quartz glass window is arranged on the sub-furnace body.

[0023] Embodiment 5: The difference from Embodiment 1 is that Figures 11 to 13 As shown (for ease of illustration, Fig.13 The furnace body 1 is tilted, a support seat 22 is fixedly arranged under the furnace shell 2, a second support seat 23 is arranged on one side of the furnace tail box 11, and an elastic structure extending into the furnace body is fixedly arranged on the second support seat 23; the elastic structure includes an arc-shaped long plate 24 fixedly connected to the second support seat 23, the arc-shaped long plate passes through the side wall of the furnace tail box and is sealed and fixedly connected at the connection of the side wall of the furnace tail box, the arc-shaped long plate is spaced from the inner wall of the furnace body but the arc-shaped long plate is closer to the bottom of the furnace cavity in the height direction of the furnace body, the curvature of the arc-shaped long plate 24 is consistent with the curvature of the inner cavity of the furnace body, and a plurality of springs 25 are arranged on the upper surface of the arc-shaped long plate at intervals, and each spring is fixedly arranged with a spring 26, one end of the spring is fixedly connected to the spring, and the other end is hinged to the upper surface of the arc-shaped long plate. In order to better implement this scheme, an opening 27 is arranged on the outer wall of the furnace tail box 11, and the opening size is slightly larger than the cross-sectional size of the whole composed of the arc-shaped long plate and the spring, and the opening is sealed and blocked by a sealant after the elastic structure extends into the furnace body.

[0024] When the material touches the shrapnel as the furnace rotates, it is lifted up. In this way, any fallen material will bounce to the middle of the furnace chamber, which plays a role in dispersing the material as much as possible in the height direction of the furnace chamber; the furnace body is tilted and the elastic structure arranged in the furnace body will distribute the material that is transported downward while rotating with the furnace as evenly as possible in the furnace chamber space in the furnace body. In this way, the calcination process is more uniform, the particle size distribution of quartz sand can be better controlled, and the generation of excessively fine particles can be avoided, which can effectively prevent the agglomeration of quartz sand powder.

[0025] Embodiment 6: The difference from Embodiment 4 is that Figures 14 to 17 As shown (for ease of illustration, Fig.14 Only one round rod and round tube are shown; Fig.15 Only one driving mechanism is shown, and the round rod and round tube are not shown; Fig.16 , Fig.17 In these two exploded schematic diagrams, the gear ring moves laterally relative to the round rod or round tube to clearly show the positional relationship between the elastic ring and the gear ring and the positional relationship between the round tube and the round rod). The gear ring 7 in the driving mechanism adopts a thicker gear ring (so that the gear ring can be set outside the furnace shell 2). A round rod 28 is fixedly set on the side of one of the two adjacent gear rings, and a round hole is set on the side of the other (the center of the round hole and the round rod are located on the same circle on the side of the gear ring, and this circle is concentric with the gear ring). A round tube 29 is set to match the round hole. The inner diameter of the round tube is larger than the diameter of the round rod, and the outer diameter of the round tube is smaller than the diameter of the round hole. A fixed sleeve is set on the round tube 29. Two elastic rings 30 are provided with a spacing between the two elastic rings, the sum of the lengths of the round rod 28 and the round tube 29 is greater than the spacing between two adjacent gear rings 7, the round tube is inserted into the round hole until the first elastic ring 30 (the two elastic rings 30 are arranged at a pipe opening close to the round tube, and the pipe opening away from the elastic ring is inserted into the round hole) is inserted into the round hole. After the round tube is inserted into the round hole, a spacing is provided between the pipe opening of the round tube 29 away from the elastic ring 30 and the end of the round rod fixedly connected to the gear ring opposite to the round tube. After the round tube is inserted into the round hole until the second elastic ring 30 is inserted into the round hole, the end of the round rod 28 of the round tube 29 opposite to the gear ring is located in the pipe opening of the round tube 29 away from the elastic ring 30.

[0026] A driving mechanism is arranged under each sub-furnace body; the furnace shell is changed into a plurality of sub-furnace shells, and a spacing is arranged between each sub-furnace shell; a dispersant adding port 21 is arranged on each sub-furnace body; and a quartz glass viewing window is arranged on the sub-furnace body.

[0027] After such arrangement, before starting the driving mechanism, the round tube between every two adjacent gear rings is inserted into the round hole so that the second elastic ring 30 is inserted into the round hole (the two elastic rings 30 are arranged at a pipe opening close to the round tube, and the pipe opening away from the elastic ring is inserted into the round hole during insertion), and then only one driving mechanism needs to be started to realize the simultaneous rotation of all the sub-furnace bodies. When the speed of a sub-furnace body 20 needs to be increased (the discharge amount of the discharge port 13 decreases, which indicates that the quartz sand powder is agglomerated more and the filter screen 16 is blocked, by observing the material transportation situation inside each sub-furnace body {also That is, when the material of a certain section of the furnace body hardly flows out from the filter screen at its lower end or a lot of material is obviously accumulated on the filter screen at its lower end, it is possible to clearly identify in which section the furnace body the powder agglomeration occurs (at the powder agglomeration location, that is, the section furnace body where the powder agglomerates rotates rapidly), the round tube is pulled outward so that the first elastic ring 30 of the round tube fits tightly against the round hole (the elastic ring is elastic and fits the round hole, which can ensure that the round tube does not slide and maintains its position) to ensure that the round rod is no longer inserted into the tube mouth of the round tube. At this time, the driving mechanism located under this section of the furnace body can be directly started to increase its rotation speed.

[0028] In this way, one driving mechanism can realize the simultaneous rotation of all the sub-furnace bodies at ordinary times, and when a certain sub-furnace body needs to be accelerated, only that sub-furnace body is driven to rotate at high speed. On the one hand, it reduces energy consumption; on the other hand, since the rotation speed of the rotary calcining furnace itself is not high, if a certain sub-furnace body needs to be accelerated separately, the round tube can be pulled out, and the operation is not troublesome.

[0029] Dispersant is still added between the two-stage filter screens 16 to cooperate with mechanical accelerated rotation to deagglomerate and effectively control the agglomeration of quartz powder, reduce the amount of dispersant, and achieve effective addition of dispersant.

[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride, characterized in that: The method comprises the following process steps which are carried out in sequence: silicon tetrachloride and water are subjected to liquid phase hydrolysis, and then the hydrolysis product is subjected to washing, solid-liquid separation, drying, calcining, grinding and screening processes to finally obtain high-purity quartz powder; A heating process is provided at the same time as the solid-liquid separation, or a heating process is provided between the washing process and the solid-liquid separation process; or a heating process is provided at the same time as the washing process.

2. The manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to claim 1, characterized in that: The temperature of the drying process is 100-200°C, the filter residue is placed in a constant temperature box for dehydration and drying to constant weight and then transferred to a calcining furnace, and the calcining temperature of the calcining process is 1300-1500°C.

3. The manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to claim 2, characterized in that: The heating process is to heat the filter residue on the filter screen involved in the solid-liquid separation process or to heat the washed product.

4. The manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to claim 1 or 3, characterized in that: The calcining furnace of the calcining process is composed of a furnace body, a furnace shell arranged outside the furnace body, a heating component arranged between the furnace shell and the furnace body, and a driving mechanism arranged outside the furnace body for driving the furnace body to rotate, wherein the heating component includes a plurality of direct-fired heating ports arranged at intervals on the outer side of the lower part of the furnace body; the length of the furnace shell is smaller than the furnace body; the driving mechanism is located near the two ends of the furnace body in the length direction of the furnace body, the driving mechanism is located under the furnace body and outside the furnace shell, and the direct-fired heating port is located inside the furnace shell.

5. The manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to claim 4, characterized in that: The driving mechanism comprises a driving motor and a transmission connected to the driving motor. A gear is fixedly arranged on the output shaft of the transmission. A gear ring is meshed with the gear. The gear ring is fixedly connected to the outer wall of the furnace body. An annular belt is also fixedly arranged on the outer wall of the furnace body. A supporting wheel is arranged to match the belt.

6. The manufacturing process for synthesizing high-purity quartz sand by liquid phase hydrolysis of silicon tetrachloride according to claim 5, characterized in that: The hydrolysis product is washed, solid-liquid separated and dried before being delivered to the feed port on the furnace body of the calcining furnace. The furnace body is heated by the direct-fired heating port. After entering the furnace body, the material is transported simultaneously with the furnace rotation and the inclined furnace body. The material is discharged after reaching the discharge port.

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