Method for removing titanium from quartz sand and device for removing titanium from quartz sand

Abstract

The application discloses a method for removing titanium from quartz sand, a granule volume method is used to measure the total volume of soaked sorghum through a submersion method, and the average volume of a single grain is calculated. Kerosene is used as a medium to effectively stabilize the measurement results, because it can reduce the absorption interference of sorghum on the test liquid. A water absorption rate correlation method is used to accurately measure the water content of the soaked (moistened) and expanded sorghum by using a rapid moisture tester, the net mass of the sorghum before expansion is obtained by deducting the water absorption rate of dry sorghum, and the density of the dry sorghum is also accurately measured by using the granule volume method. The net mass of the sorghum before expansion measured by the drying method is converted into the accurate volume of the dry sorghum, that is, the volume before expansion is obtained, and finally, the calculation formula of the expansion rate is obtained, and the expansion rate of the sorghum is calculated. The volume of the sorghum which is difficult to measure is converted into mass, and the method is easy to operate, the experimental equipment is simple, the experimental process is easy to operate, the detection time is short, the efficiency is high, and the accuracy is high.

Description

Technical Field

[0001] This invention relates to a method and apparatus for removing titanium from quartz sand, belonging to the field of chemical engineering. Background Technology

[0002] Quartz sand is an important industrial raw material, used in the manufacture of ordinary glass, quartz glass, and high-end materials such as solar panel glass and chips. Raw quartz ore contains various forms of impurities, and iron impurities can even be introduced during mining and processing, affecting its quality and limiting its applications and economic value. With the development of quartz sand applications in both traditional and cutting-edge technological fields, including the increasing demand from the new energy industry, high-purity quartz sand is mainly used in photovoltaics, semiconductors, fiber optic communication, optics, and other industries. The demand for quartz sand is gradually increasing, and the purity requirements are becoming more stringent. The level of impurities is a key indicator for measuring the quality grade of quartz sand. In the application of high-purity quartz crucibles, excessively high contents of elements such as Fe and Ti can cause discoloration and reduce the temperature resistance and mechanical strength of the crucible. To meet the needs of subsequent applications, raw quartz sand generally needs to undergo purification and other treatments to remove impurities, thus enabling better industrial utilization.

[0003] Common methods for removing impurities and purifying quartz sand include water washing and grading for desliming and iron removal, scrubbing for iron removal, magnetic separation for iron removal, flotation for iron removal, ultrasonic iron removal, acid leaching for iron removal, complexation for iron removal, and microbial leaching for iron removal.

[0004] Although various methods are commonly used for quartz sand purification, conventional acid treatment methods are often ineffective for high concentrations of titanium impurities that are poorly soluble in acids. In particular, titanium impurities in quartz sand are primarily found in rutile and ilmenite. The titanium content in quartz sand varies from 200 ppm to 10,000 ppm depending on its origin. Because rutile has a stable crystal structure and is generally inert to inorganic acids such as hydrochloric acid, conventional methods have limited effectiveness in removing titanium.

[0005] To address the difficulty in removing titanium impurities from quartz sand, this invention proposes a method that can effectively remove titanium from quartz sand, meeting the quality requirements of high-end quartz sand.

[0006] This invention utilizes the significantly increased reactivity of sulfuric acid under high-temperature conditions, and its ability to react with rutile titanium in quartz sand to form titanium sulfate. It also overcomes the limitation of sulfuric acid's boiling point, creating conditions for the reaction between quartz sand and sulfuric acid at a temperature higher than the boiling point of sulfuric acid, thus achieving titanium removal. To achieve the above objectives, the following integrated device was designed to complete the high-temperature calcination and leaching of quartz sand, thereby realizing titanium removal. Summary of the Invention

[0007] The purpose of this invention is to provide a method and apparatus for removing titanium from quartz sand. This invention utilizes the significantly increased reactivity of sulfuric acid under high-temperature conditions, enabling it to react with rutile titanium in quartz sand to form titanium sulfate. It also overcomes the limitation of sulfuric acid's boiling point, creating conditions for the reaction between quartz sand and sulfuric acid above the boiling point of sulfuric acid, thus achieving titanium removal. Simultaneously, an integrated high-temperature titanium removal apparatus is designed to complete the high-temperature calcination and leaching of quartz sand, achieving a titanium removal rate of over 75%.

[0008] The technical solution of the present invention: A method for removing titanium from quartz sand, the method comprising the following steps: (1) Sample pretreatment: Dry the quartz sand at 104-106℃ for 1.8-2.2h to remove water. Grind the dried quartz sand and pass it through a 180-220 mesh sieve to obtain quartz sand powder for later use. (2) First roasting reaction: First, high-temperature gas flow is introduced into the high-temperature de-titanium removal chamber of the de-titanium removal device through the heating gas inlet, so that the temperature inside the high-temperature de-titanium removal chamber reaches 150-300℃. Quartz sand powder is transferred from the quartz sand inlet pipe of the high-temperature de-titanium removal chamber into the high-temperature de-titanium removal chamber and spread evenly on the high-temperature resistant material filter cloth. The two electric rollers on the left and right rotate clockwise to drive the high-temperature resistant material filter cloth to run, forming a filter belt, which is also a platform for solid-liquid reaction. When the quartz sand powder runs through the high-temperature resistant material filter cloth to the underside of the sulfuric acid nozzle, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:2-3. Spraying and roasting are continued for 1-2 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature de-titanium removal chamber is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth into the filtrate tank. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Drying: High-temperature airflow is introduced again to dry the calcined quartz sand material on the high-temperature resistant filter cloth. The drying temperature is 150-300℃ and the drying time is 5-10 minutes. After drying, it is cooled to room temperature and discharged through the residue discharge port to obtain titanium-free quartz sand.

[0009] In the aforementioned step (1), the sample pretreatment is as follows: the quartz sand is dried at 105°C for 2 hours to remove water, and the dried quartz sand is ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use.

[0010] In step (2) above, during the first roasting reaction, concentrated sulfuric acid is sprayed, and the mass ratio of quartz sand powder to concentrated sulfuric acid is 1:3. The spraying and roasting are continued for 1.5 hours.

[0011] In step (2) above, the temperature inside the high-temperature titanium removal chamber during the first calcination reaction is 250-300℃.

[0012] In step (2) above, after the first roasting reaction is completed, a second roasting reaction can be carried out. High-temperature gas flow is introduced again through the heating gas inlet so that the temperature inside the high-temperature titanium removal box reaches 150-300℃. The filtrate in the filtrate tank is pumped back to the sulfuric acid nozzle through the filtrate return pipe as the spray liquid for the second roasting reaction. It is then sprayed and roasted with the quartz sand after the first roasting for a second time. The spraying and roasting is continued for 1.5 hours. After the roasting reaction is completed, the spraying is stopped and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature titanium removal box is cooled to room temperature. The remaining titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. This solution is filtered into the filtrate tank through a high-temperature resistant material filter cloth. The material on the high-temperature resistant material filter cloth is the second-roasted quartz sand.

[0013] In the aforementioned secondary roasting reaction, the temperature inside the high-temperature titanium removal chamber is 250-300℃.

[0014] The aforementioned titanium removal device for quartz sand includes a high-temperature titanium removal chamber, a filtrate tank, a high-temperature resistant filter cloth, and electric rollers. The high-temperature resistant filter cloth is fixed to the outer ring of two electric rollers, forming a closed annular filter conveyor belt structure. The two electric rollers rotate clockwise, driving the high-temperature filter cloth. The left and right electric rollers are respectively equipped with a left roller bracket and a right roller bracket. The titanium removal device is installed at a 10° angle with uneven height via the left and right roller brackets. The high-temperature resistant filter cloth is located above the two electric rollers. A high-temperature titanium removal chamber is installed on top of the filter cloth, and a filtrate tank is installed below it. The high-temperature titanium removal chamber includes a sulfuric acid pipeline, a sulfuric acid nozzle, a sulfuric acid storage tank, a filtrate tank, a temperature display, a quartz sand inlet pipe, a tail gas outlet, a heating gas inlet, and a filter residue outlet. The quartz sand inlet pipe and the tail gas outlet are located at the lower end of the high-temperature titanium removal chamber, the heating gas inlet and the filter residue outlet are located at the upper end of the high-temperature titanium removal chamber, and the sulfuric acid nozzle is located in the middle and upper part of the high-temperature titanium removal chamber. The filtrate tank is pumped to return the filtrate from the filtrate return pipe to the sulfuric acid nozzle.

[0015] The aforementioned sulfuric acid nozzle is connected to the sulfuric acid storage tank via a sulfuric acid pipeline.

[0016] The aforementioned high-temperature resistant filter cloth can withstand temperatures up to 300°C. On both sides of the high-temperature resistant filter cloth, additional retaining rings are added to ensure the formation of a certain liquid accumulation layer.

[0017] The sulfuric acid mist generated in the aforementioned high-temperature titanium removal device housing can be discharged to the tail gas recovery device through the tail gas outlet. The temperature inside the high-temperature titanium removal device housing can be displayed by a temperature display to ensure the temperature inside the high-temperature titanium removal device housing. The filtrate collected in the filtrate tank can be discharged from the filtrate discharge port.

[0018] Beneficial effects of the present invention 1. The titanium removal rate of the single-calcination process of this invention reaches 75.68%, and the titanium content of the quartz sand after titanium removal is as low as 56 ppm, which is at a low level. If multiple titanium removal processes are used, the titanium content can be further reduced.

[0019] 2. The device of the present invention has the functions of solid-liquid reaction, high temperature heating, tail gas acid mist recovery, step-by-step spraying of sulfuric acid, and continuous acid leaching. It also has the functions of solid-liquid separation, automatic slag discharge, filtrate collection and recycling. 2. The lower part of the device consists of two rollers on the left and right, which drive the high-temperature resistant filter cloth to rotate, forming a filter belt. This belt also serves as a platform for the solid-liquid reaction. The high-temperature resistant filter cloth can withstand temperatures up to 300℃ and is resistant to acid corrosion. When the filter cloth passes over the two rollers, it forms a concave shape through the support structure, facilitating liquid accumulation, prolonging the solid-liquid contact time, and promoting the leaching process. Simultaneously, baffles are added to both sides of the filter cloth to ensure the formation of a certain liquid accumulation layer.

[0020] 4. The upper filter cloth, along with the material on it, is enclosed in a sealed high-temperature titanium removal device. This device introduces a high-temperature airflow to heat the quartz sand on the entire filter cloth, controlling the temperature inside the device within the range of 180-250℃. At this temperature, the high-temperature enhanced reaction between the quartz sand and sulfuric acid is completed. 5. Due to the high-temperature titanium removal device, the quartz sand is repeatedly subjected to acid leaching and dry burning, much like taking a sauna. During dry burning, the high temperature allows the rutile titanium in the quartz sand to react with sulfuric acid, producing titanium sulfate. Subsequently, in the spraying stage, it is leached with sulfuric acid, and the titanium sulfate dissolves in the sulfuric acid and enters the solution. After several repetitions, the titanium in the quartz sand is separated, resulting in clean quartz sand, which is then processed from high-end ( Figure 1 The filtrate is then discharged and enters a filtrate tank below the filter cloth. The filtrate in the filtrate tank is then pumped back to the nozzle for acid spraying. Once the concentration of titanium ions in the filtrate tank reaches a certain level, further purification treatment is performed.

[0021] 6. The device is installed at a 10° incline with uneven surfaces. Raw materials are added from the lower end and slowly ascend the slope to the upper end. Acid is sprayed from the middle and upper sections through multiple spray nozzles to repeatedly wash the quartz sand. There is no spray at the highest end to ensure that the discharged slag is dry. Attached Figure Description

[0022] Figure 1 Plan view of the high-temperature titanium removal device; Figure 2 Schematic diagram of high-temperature resistant filter cloth; Figure 3 Left sectional view of the high-temperature titanium removal device housing.

[0023] Explanation of reference numerals in the attached figures: 1: High-temperature titanium removal chamber 101, sulfuric acid pipeline 102, sulfuric acid nozzle 103, sulfuric acid storage tank 104, temperature display 105, quartz sand inlet pipe 106, exhaust gas outlet 107, heating gas inlet 108 and filter residue outlet 109, high-temperature resistant filter cloth 201, retaining ring 202, left electric roller 301, right electric roller 302, left support 303, right support 304, filtrate tank 401, pump 402, filtrate return pipe 403, filtrate discharge port 404. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0025] Example 1: Method for removing titanium from quartz sand (1) Sample pretreatment: The quartz sand was dried at 105℃ for 2 hours to remove water. The dried quartz sand was then ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use. (2) First calcination reaction: First, a high-temperature gas flow is introduced into the high-temperature titanium removal chamber 101 of the titanium removal device through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 250-300℃, quartz sand powder is transferred from the quartz sand inlet pipe 106 into the high-temperature titanium removal chamber 101 and spread evenly on the high-temperature resistant material filter cloth 201. The left electric roller 301 and the right electric roller rotate clockwise at the same time to drive the high-temperature resistant material filter cloth 201 to run, forming a filter belt, which also serves as a platform for solid-liquid reaction. When the quartz sand powder passes through the high-temperature resistant material filter cloth 201 and reaches below the sulfuric acid nozzle 103, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:3. Spraying and roasting are continued for 1.5 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature airflow is also stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth 201 into the filtrate tank 401. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Drying: Introduce high-temperature airflow again to dry the calcined quartz sand material on the high-temperature resistant filter cloth 201. When the temperature displayed on the temperature display 105 reaches 250-300℃, dry for 8 minutes, cool to room temperature, and discharge through the residue discharge port 109 to obtain titanium-deionized quartz sand.

[0026] The sulfuric acid mist generated in the high-temperature titanium removal unit can be discharged to the exhaust gas recovery device through the exhaust outlet.

[0027] Example 2: Method for removing titanium from quartz sand (1) Sample pretreatment: The quartz sand was dried at 106℃ for 2.2h to remove water. The dried quartz sand was then ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use. (2) First calcination reaction: First, a high-temperature gas flow is introduced into the high-temperature titanium removal chamber 101 of the titanium removal device through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 250-300℃, quartz sand powder is transferred from the quartz sand inlet pipe 106 into the high-temperature titanium removal chamber 101 and spread evenly on the high-temperature resistant material filter cloth 201. The left electric roller 301 and the right electric roller rotate clockwise at the same time to drive the high-temperature resistant material filter cloth 201 to run, forming a filter belt, which is also the carrier for the solid-liquid reaction. When the quartz sand powder passes through the high-temperature resistant material filter cloth 201 and reaches below the sulfuric acid nozzle 103, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:2. Spraying and roasting continues for 2 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature airflow is also stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth 201 into the filtrate tank 401. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Drying: Introduce high-temperature airflow again to dry the calcined quartz sand material on the high-temperature resistant filter cloth 201. When the temperature displayed on the temperature display 105 reaches 250-300℃, dry for 5 minutes, cool to room temperature, and discharge through the residue discharge port 109 to obtain titanium-deionized quartz sand.

[0028] Example 3: Method for removing titanium from quartz sand (1) Sample pretreatment: The quartz sand was dried at 104℃ for 1.8h to remove water. The dried quartz sand was then ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use. (2) First calcination reaction: First, a high-temperature gas flow is introduced into the high-temperature titanium removal chamber 101 of the titanium removal device through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 150-200℃, quartz sand powder is transferred from the quartz sand inlet pipe 106 into the high-temperature titanium removal chamber 101 and spread evenly on the high-temperature resistant material filter cloth 201. The left electric roller 301 and the right electric roller rotate clockwise at the same time to drive the high-temperature resistant material filter cloth 201 to run, forming a filter belt, which is also the carrier for the solid-liquid reaction. When the quartz sand powder passes through the high-temperature resistant material filter cloth 201 and reaches below the sulfuric acid nozzle 103, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:3. Spraying and roasting are continued for 1 hour. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature airflow is also stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth 201 into the filtrate tank 401. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Drying: Introduce high-temperature airflow again to dry the calcined quartz sand material on the high-temperature resistant filter cloth 201. When the temperature displayed on the temperature display 105 reaches 150-200℃, dry for 10 minutes, cool to room temperature, and discharge through the residue discharge port 109 to obtain titanium-deionized quartz sand.

[0029] Example 4: Method for removing titanium from quartz sand (1) Sample pretreatment: The quartz sand was dried at 105℃ for 2 hours to remove water. The dried quartz sand was then ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use. (2) First calcination reaction: First, a high-temperature gas flow is introduced into the high-temperature titanium removal chamber 101 of the titanium removal device through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 250-300℃, quartz sand powder is transferred from the quartz sand inlet pipe 106 into the high-temperature titanium removal chamber 101 and spread evenly on the high-temperature resistant material filter cloth 201. The left electric roller 301 and the right electric roller rotate clockwise at the same time to drive the high-temperature resistant material filter cloth 201 to run, forming a filter belt, which also serves as a platform for solid-liquid reaction. When the quartz sand powder passes through the high-temperature resistant material filter cloth 201 and reaches below the sulfuric acid nozzle 103, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:3. Spraying and roasting are continued for 1.5 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature airflow is also stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth 201 into the filtrate tank 401. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Secondary roasting reaction: After the first roasting reaction is completed, a high-temperature gas flow is introduced again through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 250-300℃, the filtrate in the filtrate tank 401 is returned to the sulfuric acid nozzle 103 through the filtrate return pipe 403 via the pump 402 as the spray liquid for the secondary roasting reaction. It is then sprayed and roasted with the quartz sand after the first roasting for a second time. The spraying and roasting is continued for 1.5 hours. After the roasting reaction is completed, the spraying is stopped and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The remaining titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution, which is filtered into the filtrate tank 401 through the high-temperature resistant material filter cloth 201. The material on the high-temperature resistant material filter cloth is the quartz sand that has been roasted twice.

[0030] (4) Drying: Introduce high-temperature airflow again to dry the quartz sand material that has been calcined twice on the high-temperature resistant filter cloth 201. When the temperature displayed on the temperature display 105 reaches 250-300℃, dry for 8 minutes, cool to room temperature, and discharge through the residue discharge port 109 to obtain titanium-deionized quartz sand.

[0031] Example 5: Method for removing titanium from quartz sand (1) Sample pretreatment: The quartz sand was dried at 105.5℃ for 2.2h to remove water. The dried quartz sand was then ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use. (2) First calcination reaction: First, a high-temperature gas flow is introduced into the high-temperature titanium removal chamber 101 of the titanium removal device through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 200-250℃, quartz sand powder is transferred from the quartz sand inlet pipe 106 into the high-temperature titanium removal chamber 101 and spread evenly on the high-temperature resistant material filter cloth 201. The left electric roller 301 and the right electric roller rotate clockwise at the same time to drive the high-temperature resistant material filter cloth 201 to run, forming a filter belt, which also serves as a platform for solid-liquid reaction. When the quartz sand powder passes through the high-temperature resistant material filter cloth 201 and reaches below the sulfuric acid nozzle 103, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:2.5. Spraying and roasting are continued for 1.8 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature airflow is also stopped. The temperature inside the high-temperature titanium removal chamber 101 is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth 201 into the filtrate tank 401. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Secondary roasting reaction: After the first roasting reaction is completed, a high-temperature gas flow is introduced again through the heating gas inlet 108. When the temperature displayed on the temperature display 105 reaches 200-250℃, the filtrate in the filtrate tank 401 is returned to the sulfuric acid nozzle 103 through the filtrate return pipe 403 via the pump 402 as the spray liquid for the secondary roasting reaction. It is then sprayed and roasted with the quartz sand after the first roasting for a secondary roasting reaction. The spraying and roasting continues for 1.8 hours. After the roasting reaction is completed, the spraying is stopped and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature titanium removal box 101 is cooled to room temperature. The remaining titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution, which is filtered into the filtrate tank 401 through the high-temperature resistant material filter cloth 201. The material on the high-temperature resistant material filter cloth is the quartz sand that has been roasted twice.

[0032] (4) Drying: Introduce high-temperature airflow again to dry the quartz sand material that has been calcined twice on the high-temperature resistant filter cloth 201. When the temperature displayed on the temperature display 105 reaches 200-250℃, dry for 10 minutes, cool to room temperature, and discharge through the residue discharge port 109 to obtain titanium-deionized quartz sand.

[0033] Extensive experimental research was conducted to demonstrate the effectiveness of this invention. The results of this experimental research are as follows: 1. Titanium removal experiment 1.1 First group of experiments (single roasting) Sample pretreatment: Dry the quartz sand in an oven at 105℃ for 2 hours to remove water. Weigh 10.0g of the dried quartz sand and transfer it to a mortar for grinding. Grind the quartz sand through a 200-mesh sieve to ensure uniform particle size and increase the reaction contact area to obtain quartz sand powder.

[0034] Calcination reaction: Add 20.0g of concentrated sulfuric acid (mass ratio of quartz sand powder to concentrated sulfuric acid 1:2) to the treated quartz sand, place it on a hot plate, and calcine at 150-200℃ for 1.5 hours until vigorous white smoke is generated (the endpoint of the reaction).

[0035] Post-processing: After the reaction system is cooled to room temperature, it is transferred to a Buchner funnel for filtration; the crucible and filter residue are rinsed with distilled water, the filtrate is diluted to a 50 mL volumetric flask, and the filter residue is dried.

[0036] Table 1 Residual Amount of Quartz Sand After Single Firing 1.2. Second group of experiments (secondary roasting) Sample pretreatment: The procedure is the same as the first group, ensuring that the initial state of the quartz sand is the same and eliminating the interference of pretreatment differences on the experiment.

[0037] Calcination reaction: First calcination: Add 20.0g concentrated sulfuric acid and calcine at 150-200℃ for 1.5 hours until white smoke is generated; Secondary roasting: After the system has cooled slightly, add 20.0g of concentrated sulfuric acid and continue roasting at the same temperature until white smoke is generated, which takes about 3 hours in total; stir with a glass rod throughout the process to ensure uniform reaction.

[0038] Post-processing: Same as the first group, filter, bring the filtrate to 50 mL, and dry the filter residue.

[0039] Table 2 Residual Amount of Quartz Sand After Secondary Calcination 2. Colorimetric Experiment and Detitanium Removal Rate Calculation 2.1 Initial determination of titanium content in quartz sand: Table 3 Quartz Sand Content The mass fraction of titanium was determined to be approximately 0.2361%, which translates to 2361.3 micrograms of titanium per gram of quartz sand. This data served as the basis for calculating the titanium removal rate.

[0040] Colorimetric experiment: Take 12.5 mL of the filtrate from the two sets of experiments after dilution and place them in 50 mL colorimetric tubes respectively; add 20 mL of deionized water, 5 mL of hydrochloric acid solution (hydrochloric acid solution is obtained by mixing concentrated hydrochloric acid and water in a volume ratio of 1:1), and 2.5 mL of ascorbic acid solution in sequence, shake well and let stand for 5 minutes (to reduce titanium ions); then add 5 mL of DAPM solution, dilute to the mark, shake well and let stand for 40 minutes to allow titanium ions to fully complex with DAPM and develop color.

[0041] Visual observation shows that the second group of filtrates is darker in color, indicating a higher amount of titanium removal.

[0042] 2.2 Calculation of titanium removal rate: The absorbance of the first and second groups of colorimetric solutions was measured at 390 nm (the characteristic absorption wavelength of the titanium-DAPM complex) using a spectrophotometer. By preparing a titanium standard solution, an absorbance-concentration standard curve was plotted (equation: y = 69x - 0.1227 (x is absorbance, y (µg / mL) is concentration)). The titanium concentration in the colorimetric tube was calculated by substituting the absorbance values ​​of the first and second groups.

[0043] Detitanium removal rate formula: Table 4 Comparison of Calcination Times for Quartz Sand 2.3 Calculation process: The titanium content per gram of quartz sand is known to be 2361.3 μg. First group of titanium removal rates The absorbance of the first group was measured to be 0.6830, and the volume of the filtrate was adjusted to 50 mL. First, calculate the titanium concentration in the colorimetric tube.

[0044] Substituting the data into the absorbance-concentration standard curve equation y = 69x - 0.1227 (where x is absorbance and y is concentration), we get: The titanium concentration in the colorimetric tube is approximately 47.0043 μg / mL. Substituting the known data into the above formula, we get... The titanium removal rate of the first group (single roasting) was 39.81%.

[0045] Similarly, the titanium removal rate of the second group (secondary roasting) was calculated to be 66.07%. The calculated detitanium removal rates for the first and second groups were 39.81% and 58.53%, respectively.

[0046] 3. Experiment to investigate the effect of the amount of sulfuric acid added on the results. 3.1 Sulfuric acid usage grouping To further investigate the influence of process parameters on the titanium removal effect, an experiment was conducted to explore the effect of the amount of sulfuric acid added on the results. Three groups were set up, each using 10g of dried and ground quartz sand, with the ratio of quartz sand to concentrated sulfuric acid controlled at 1:1, 1:2, and 1:3, respectively. Each group was calcined at 150-200℃ until vigorous white fumes were generated, then filtered and diluted to 125mL (the filter residue was preserved for analysis of titanium residue under different sulfuric acid dosages, etc.). The colorimetric experimental procedure described above was then followed, and finally, the absorbance was measured using a spectrophotometer, and the titanium removal rate was calculated using the formula described above. The results are as follows: Table 5. Effect of Sulfuric Acid Usage on Titanium Removal Rate 3.2 Further testing was conducted on the residual titanium content in the primary and secondary roasted filter residues with three different proportions. Dissolving the filter residue: Weigh approximately 1g of the calcined filter residue sample, accurate to 0.001g. Place the sample in an F4 beaker, moisten with a small amount of water, add 1mL of concentrated sulfuric acid and 10mL of hydrofluoric acid, and evaporate on a low-temperature electric furnace until white fumes of sulfur trioxide are emitted. Repeat the treatment once, gradually increasing the temperature to drive off the sulfur trioxide, and then cool. Dissolve the sulfur trioxide in 5mL of hydrochloric acid and an appropriate amount of water by heating, cool, and bring the volume to 50mL. Dilute with water to the mark and mix well.

[0047] Color development: 12.5 mL of each of the three solutions after dilution was placed in a 50 mL colorimetric tube; 20 mL of deionized water, 5 mL of hydrochloric acid solution (hydrochloric acid solution is obtained by mixing concentrated hydrochloric acid and water in a volume ratio of 1:1), and 2.5 mL of ascorbic acid solution were added sequentially, shaken well and allowed to stand for 5 minutes (to reduce titanium ions); then 5 mL of DAPM solution was added, diluted to the mark, shaken well and allowed to stand for 40 minutes to allow the titanium ions to fully complex with DAPM and develop color.

[0048] Measurement and calculation: For the third group of colorimetric solutions, the absorbance was measured at 390 nm (the characteristic absorption wavelength of the titanium-DAPM complex) using a spectrophotometer; by preparing a titanium standard solution, an absorbance-concentration standard curve was plotted (equation: y = 69x - 0.1227 (x is absorbance, y (µg / mL) is concentration)).

[0049] Formula for calculating titanium residue: (Note: The titanium residue rate refers to the percentage of unremoved titanium to the titanium in the original quartz sand, reflecting the content of unremoved titanium.) The calculation results are as follows: Table 6. Effects of sulfuric acid usage and calcination times on titanium residue in quartz sand. 3.3 Calculation process: The titanium content per gram of quartz sand is known to be 2361.3 μg. 1) Residual rate of titanium in 1:1 group The absorbance of the 1:1 group was measured to be 0.0194, and the filtrate volume was adjusted to 125 mL. First, calculate the titanium concentration in the colorimetric tube: Substituting the data into the absorbance-concentration standard curve equation y = 69x - 0.1227 (where x is absorbance and y is concentration), we get: The titanium concentration in the colorimetric tube is approximately 1.2159 μg / mL. Substituting the known data into the above formula, we get... The residual rate of titanium in the 1:1 group is 10.30%.

[0050] Similarly, the residual rate of titanium in the 1:2 group is 10.30%; The residual rate of titanium in the 1:3 ratio was 10.18%. The residual rate of titanium in the secondary calcination group was 6.73%. The results of the titanium removal rate show that the removal rate increases with the increase of the amount of concentrated sulfuric acid added. This is because, within a certain range, increasing the amount of concentrated sulfuric acid provides more sufficient reaction reagents for the removal reaction of titanium in quartz sand, promoting the chemical reaction between titanium and concentrated sulfuric acid, thereby improving the titanium removal effect.

[0051] 4. Optimize the experiment The titanium removal methods used in the following experiments all employed a single calcination reaction, with the reaction temperature increased to 250-300℃. The titanium content and removal rate of the quartz sand after titanium removal were then measured. The titanium removal effect of replacing concentrated sulfuric acid with hydrogen peroxide was also compared.

[0052] Table 7. Effect of calcination temperature (250-300℃) on titanium removal rate of quartz sand (Note: The original quartz sand contains 0.023% titanium) As shown in the table above, although adding hydrogen peroxide and mixing with quartz sand can reduce the amount of sulfuric acid used, the titanium removal effect is still not as good as adding only 30g of concentrated sulfuric acid. Furthermore, the method of removing titanium from quartz sand by simply adding concentrated sulfuric acid and spraying it at high temperature is simple, easier to operate, and suitable for industrial production.

[0053] 5. Experimental Conclusions 5.1. After optimization, the titanium removal rate of the single-calcination process reached 75.68%, and the titanium content of the quartz sand after titanium removal was as low as 56 ppm, which is at a low level. If multiple titanium removal processes are used, the titanium content can be further reduced.

[0054] 5.2. The amount of concentrated sulfuric acid used is a key factor affecting the titanium removal effect and provides a basis for subsequent process optimization, but it needs to be balanced with environmental and other factors.

Claims

1. A method for removing titanium from quartz sand, characterized in that: The method is performed according to the following steps: (1) Sample pretreatment: Dry the quartz sand at 104-106℃ for 1.8-2.2h to remove water. Grind the dried quartz sand and pass it through a 180-220 mesh sieve to obtain quartz sand powder for later use. (2) First roasting reaction: First, high-temperature gas flow is introduced into the high-temperature de-titanium removal chamber of the de-titanium removal device through the heating gas inlet, so that the temperature inside the high-temperature de-titanium removal chamber reaches 150-300℃. Quartz sand powder is transferred from the quartz sand inlet pipe of the high-temperature de-titanium removal chamber into the high-temperature de-titanium removal chamber and spread evenly on the high-temperature resistant material filter cloth. The two electric rollers on the left and right rotate clockwise to drive the high-temperature resistant material filter cloth to run, forming a filter belt, which is also a platform for solid-liquid reaction. When the quartz sand powder runs through the high-temperature resistant material filter cloth to the underside of the sulfuric acid nozzle, concentrated sulfuric acid is sprayed. The mass ratio of quartz sand powder to concentrated sulfuric acid is 1:2-3. Spraying and roasting are continued for 1-2 hours. After the roasting reaction is completed, the spraying of sulfuric acid is stopped, and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature de-titanium removal chamber is cooled to room temperature. The titanium sulfate in the quartz sand dissolves in the sulfuric acid to form a solution. The solution is filtered through the high-temperature resistant material filter cloth into the filtrate tank. The material on the high-temperature resistant material filter cloth is the roasted quartz sand. (3) Drying: High-temperature airflow is introduced again to dry the calcined quartz sand material on the high-temperature resistant filter cloth. The drying temperature is 150-300℃ and the drying time is 5-10 minutes. After drying, it is cooled to room temperature and discharged through the residue discharge port to obtain titanium-free quartz sand.

2. The method for removing titanium from quartz sand according to claim 1, characterized in that: In step (1), the sample pretreatment is as follows: the quartz sand is dried at 105°C for 2 hours to remove water, and the dried quartz sand is ground and passed through a 200-mesh sieve to obtain quartz sand powder for later use.

3. The method for removing titanium from quartz sand according to claim 1, characterized in that: In step (2), during the first roasting reaction, concentrated sulfuric acid is sprayed, and the mass ratio of quartz sand powder to concentrated sulfuric acid is 1:

3. The spraying and roasting are continued for 1.5 hours.

4. The method for removing titanium from quartz sand according to claim 1, characterized in that: In step (2), the temperature inside the high-temperature titanium removal chamber during the first calcination reaction is 250-300℃.

5. The method for removing titanium from quartz sand according to claim 1, characterized in that: In step (2), after the first roasting reaction is completed, a second roasting reaction can be carried out. High-temperature gas flow is introduced again through the heating gas inlet, so that the temperature inside the high-temperature titanium removal box is 150-300℃. The filtrate in the filtrate tank is pumped back to the sulfuric acid nozzle through the filtrate return pipe as the spray liquid for the second roasting reaction. It is sprayed and roasted with the quartz sand after the first roasting for a second time. The spraying and roasting is continued for 1.5 hours. After the roasting reaction is completed, the spraying is stopped and the introduction of high-temperature gas flow is stopped. The temperature inside the high-temperature titanium removal box is cooled to room temperature. The remaining titanium sulfate in the quartz sand dissolves in sulfuric acid to form a solution. It is filtered into the filtrate tank through the high-temperature resistant material filter cloth. The material on the high-temperature resistant material filter cloth is the second roasted quartz sand.

6. The method for removing titanium from quartz sand according to claim 5, characterized in that: In the secondary roasting reaction, the temperature inside the high-temperature titanium removal chamber is 250-300℃.

7. The titanium removal apparatus used in the method for removing titanium from quartz sand according to any one of claims 1-6, characterized in that: The titanium removal device includes a high-temperature titanium removal chamber, a filtrate tank, a high-temperature resistant filter cloth, and electric rollers. The high-temperature resistant filter cloth is fixed to the outer ring of two electric rollers, forming a closed annular filter conveyor belt structure. The two electric rollers rotate clockwise, driving the high-temperature filter cloth. The left and right electric rollers are respectively equipped with a left roller bracket and a right roller bracket. The titanium removal device is installed at a 10° uneven angle using the left and right roller brackets. A high-temperature resistant filter cloth is positioned above the two electric rollers. The system includes a high-temperature titanium removal chamber with a filtrate tank at the bottom. The high-temperature titanium removal chamber includes a sulfuric acid pipeline, a sulfuric acid nozzle, a sulfuric acid storage tank, a filtrate tank, a temperature display, a quartz sand inlet pipe, a tail gas outlet, a heating gas inlet, and a filter residue outlet. The quartz sand inlet pipe and the tail gas outlet are located at the lower end of the high-temperature titanium removal chamber, while the heating gas inlet and the filter residue outlet are located at the upper end. The sulfuric acid nozzle is located in the middle and upper parts of the high-temperature titanium removal chamber. The filtrate tank is pumped to return the filtrate from the filtrate return pipe to the sulfuric acid nozzle.

8. The titanium removal device according to claim 7, characterized in that: The sulfuric acid nozzle is connected to the sulfuric acid storage tank via a sulfuric acid pipeline.

9. The titanium removal device according to claim 7, characterized in that: The high-temperature resistant filter cloth can withstand temperatures up to 300°C. On both sides of the high-temperature resistant filter cloth, additional retaining rings are added to ensure the formation of a certain liquid accumulation layer.

10. The titanium removal device according to claim 7, characterized in that: The sulfuric acid mist generated in the high-temperature titanium removal device can be discharged through the exhaust port. The temperature inside the high-temperature titanium removal device can be displayed on the temperature display to ensure the temperature inside the high-temperature titanium removal device. The filtrate collected in the filtrate tank can be discharged from the filtrate discharge port.

Images