Process for preparing and processing high-purity quartz sand from quartz ore with high iron and aluminum content

Abstract

The invention relates to the technical field of high-purity quartz sand preparation, in particular to a process for producing high-purity quartz sand from quartz ore with high iron and aluminum content, which comprises the processes of coarse crushing, screening, acid leaching, roasting and water quenching, fine crushing, screening, magnetic separation, acid scrubbing, flotation, acid pickling, chlorination purification, magnetic separation and the like. And metal impurities and non-metal impurities in the ore are systematically removed. And through rough crushing and screening, ore with high impurity content is screened out in advance, and interference of impurities to subsequent procedures is reduced. And it is ensured that in the subsequent fine crushing and flotation process, the content of impurities in the quartz ore is small, it is avoided that due to excessive impurities, the subsequent treatment difficulty is increased, and the production efficiency is improved. And then the links of acid leaching, roasting water quenching, flotation, acid pickling, chlorination purification and the like are carried out, so that common impurities in the ore can be effectively removed. Through multiple acid treatment and high-temperature chlorination purification, it is ensured that impurities are converted into volatile compounds and thoroughly removed, and the purity of the quartz sand is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity quartz sand preparation, and in particular to a process for preparing and processing high-purity quartz sand from quartz ore with high iron and aluminum contents. Background Art

[0002] In the application field of quartz sand, high-purity quartz sand, especially quartz sand with low iron and low aluminum content, is widely used in high-tech fields such as semiconductors, optical fibers, solar photovoltaics, electrical appliances, and electronic materials. However, natural quartz ore usually contains a certain amount of impurities such as iron and aluminum. The presence of these impurities will seriously affect the purity of quartz sand, and then affect its application effect in high-precision fields. Therefore, how to effectively remove impurities such as iron and aluminum in quartz ore and improve the purity of quartz sand has become a core technical problem in the production of high-end quartz sand.

[0003] As important indicators of high-purity quartz sand, the content of iron and aluminum elements is of great significance in the actual production and processing of high-purity quartz sand. Especially for iron-containing quartz ores such as magnetite and hematite, a series of processes must be used to remove mineral impurities such as iron and aluminum in quartz sand to meet the stringent requirements of high-purity quartz sand for the content of impurity elements. At present, most companies in the industry still use "coarse crushing-roasting and water quenching-fine crushing-screening-magnetic separation-flotation-pickling-purification operations". Usually, for quartz ores with normal iron and aluminum content, the process can reach the level of high-purity quartz sand (SiO2≥99.998), but for ores with high iron and aluminum content, the standard cannot be met, or such mined quartz ores will not be used. Therefore, a large amount of resources and energy are wasted.

[0004] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0005] The first object of the present invention is to provide a process for preparing and processing high-purity quartz sand from quartz ore with high iron and aluminum contents, which can effectively reduce the content of iron and aluminum elements in quartz sand, improve the quality of high-purity quartz sand, and avoid increasing the waste of resources and energy caused by repeated processing.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A process for producing high-purity quartz sand from quartz ore with high iron and aluminum content, including the processes of "coarse crushing - screening - acid leaching - roasting and water quenching - fine crushing - screening - magnetic separation - acid scrubbing - flotation - acid washing - chlorination purification - magnetic separation", and the specific steps are as follows: S01: Use jaw crusher to roughly crush the raw ore to obtain coarse ore with an average particle size of 1~5cm; Preferably, in step S01, the ore with a particle size greater than 5 cm after coarse crushing is returned to the jaw crusher for further coarse crushing, and the ore with a particle size less than 1 cm is collected as quartz crushed material for standby use.

[0007] Specifically, the ore after coarse crushing needs to be graded by screening equipment. The present invention adopts a vibrating screen or a multi-layer screening machine to ensure the accurate separation of ores of different particle sizes. Among them, through two layers of screens, ores larger than 5cm, 1~5cm and smaller than 1cm are screened separately to improve screening efficiency and accuracy. For ores with a particle size larger than 5cm screened out, an automatic return system is set to return them directly to the jaw crusher through a conveyor belt or an automatic hopper for cyclic crushing to reduce the need for manual operation and improve production efficiency. Ore particles smaller than 1cm are directly sent to storage or standby processes through a collection bin or a conveying system.

[0008] The invention uses particle size screening and cyclic crushing to return large-size ores to the jaw crusher for re-crushing in time, thus avoiding the impact of oversized particles in subsequent processes on processing quality. Ores smaller than 1 cm are directly collected for use, reducing redundant crushing steps, optimizing the entire process, and improving production capacity and efficiency.

[0009] S02: Screen the coarse ore and pick out the coarse ore with more impurities; Preferably, in step S02, the coarse ore with more impurities is a coarse ore with mica and feldspar content greater than 70%. Compared with quartz ore, mica and feldspar have obvious differences in color, gloss and texture. Mica ore usually has a relatively smooth surface, strong reflective properties, and is especially easy to identify under light. Compared with quartz, feldspar has more diverse colors and a rougher surface. Specifically, a high-precision visual recognition system (such as industrial cameras and image processing technology) is used to monitor the coarse ore online, and ores with higher impurity content are identified by visual features such as color, gloss, and shape, and are automatically separated. At the same time, impurities such as light mica and feldspar can also be further separated by air separation or density sorting. These minerals usually have a low density and can be effectively removed by airflow or hydraulic separation technology.

[0010] The present invention can significantly reduce the content of impurities such as aluminum and potassium in quartz sand by effectively removing high-impurity ores containing mica, feldspar, etc. in the early stage, ensuring that higher-purity quartz sand is produced in the subsequent process to meet industrial or electronic grade requirements. At the same time, it can greatly reduce the workload of subsequent processes (such as acid leaching, magnetic separation and chlorination purification), shorten the acid leaching time, reduce the consumption of acid and other reagents, and improve the processing efficiency and economy of subsequent processes.

[0011] S03: Acid leaching is performed on the coarse ore after screening, wherein the acid used for acid leaching is a mixed acid of hydrochloric acid, hydrofluoric acid and oxalic acid, and the acid leaching time is 24-72 hours, and then washed with pure water; During the acid leaching process, the temperature is controlled within the range of 40~50℃ to accelerate the reaction rate between the acid and impurities. Increasing the temperature can enhance the activity of the acid and shorten the reaction time, but too high a temperature may cause the destruction of the quartz crystal structure, so it should not exceed 50℃. To ensure that the acid is in full contact with the ore surface, continuous stirring or intermittent stirring can also be used during the acid leaching process. This can improve the reaction efficiency between the acid and impurities and promote the dissolution of metal ions. The post-acid leaching rinse step uses high-pressure pure water spraying to ensure that the acid and metal ions on the ore surface are completely removed to avoid the influence of residual acid on subsequent processes. Cleanliness can also be ensured by multi-stage rinsing.

[0012] Preferably, in step S03, the mixing ratio of hydrochloric acid, hydrofluoric acid and oxalic acid is 40-60:10-30:10-20. The hydrochloric acid is industrial hydrochloric acid with a concentration of 15%-25%. Based on the weight of the ore, the amount of hydrochloric acid used is 20-50 kg / ton of ore, the concentration of hydrofluoric acid is 5%-10%, the amount is 5-20 kg / ton of ore, and the concentration of oxalic acid is 5%-10%, the amount is 3-10 kg / ton of ore.

[0013] The present invention can effectively remove different types of impurities (such as iron, aluminum, calcium, titanium, etc.) by reasonably adjusting the ratio of hydrochloric acid, hydrofluoric acid and oxalic acid. Hydrochloric acid is mainly used to dissolve oxides such as iron and aluminum, hydrofluoric acid can dissolve silicate impurities, and oxalic acid is used to form insoluble complexes with metal impurities. The above components can effectively improve the impurity removal efficiency.

[0014] S04: roasting and water quenching the clean ore after acid leaching; Preferably, in step S04, the ore rinsed after acid leaching is sent to a roasting furnace at 800°C-1500°C for roasting for 2-5 hours. The ore is red when the roasting material is discharged. Specifically, when the ore reaches dark red or orange-red, the roasting can be considered complete. This is a sign that the temperature inside the quartz ore is uniform and the impurities have begun to loosen. Then the roasted quartz sand is placed in water for water quenching and rapidly cooled with cooling water. The temperature of the cooling water during the water quenching process is between 10°C and 25°C. The lower water temperature helps the quartz ore to cool down quickly during water quenching, thereby further cracking and falling off the impurities inside the ore. The water quenching time is controlled at 10-30 minutes until the ore is completely cooled. The water quenching process further breaks the gas-liquid inclusions and impurities inside the ore through rapid cooling, which facilitates the removal of impurities in the subsequent processing process. At the same time, water quenching can harden the quartz crystal and enhance its mechanical strength.

[0015] S05: After the roasted and water-quenched ore is finely crushed and sanded, it is screened using a wet vibrating screen to obtain quartz sand particles of 60-160 mesh; during wet vibrating screening, an appropriate amount of water flow helps to avoid adhesion of quartz sand particles and prevent clogging of the screen. The water flow rate is controlled within the range of 30-50 liters of water per ton of quartz sand to ensure the cleaning effect while avoiding waste of water resources.

[0016] Preferably, in step S05, the ore with a particle size greater than 60 mesh after fine crushing is returned for further fine crushing, and the ore with a particle size less than 160 mesh is collected as quartz fine material for standby use. The present invention adopts different screen levels for step-by-step screening to ensure that large particles above 60 mesh are returned for further crushing, and fine materials below 160 mesh are separated. Double-layer or multi-layer screens are specifically configured to accurately separate quartz sands of different particle size ranges. The configuration of multi-layer screens can improve the screening accuracy, prevent quartz sands of uneven particle sizes from entering subsequent processes, and improve the quality consistency of finished quartz sands. The return of larger particles for further crushing can increase the output rate of quartz sand fine materials.

[0017] S06: The obtained quartz sand particles are magnetically separated by an electromagnetic separator, and the background magnetic field strength of the electromagnetic separator is 8000GS; a multi-stage magnetic separation process is specifically adopted. The first magnetic separation removes the main magnetic impurities (such as iron filings, magnetic dust, etc.), and the second or subsequent magnetic separation further removes the residual trace magnetic impurities to ensure that the purity meets the requirements.

[0018] Preferably, in step S06, the magnetic separation time is 1-2 hours. The temperature of the magnetic separation environment is 20-30°C, and the humidity is maintained between 30% and 50%. This can reduce particle adhesion, avoid clogging of the magnetic separator, and help improve the magnetic separation efficiency, ensuring that magnetic impurities at each stage can be effectively removed.

[0019] S07: Use a single tank flotation machine to perform acid scrubbing and flotation operations on quartz sand particles; As a preferred embodiment, in step S07, the quartz sand particles are scrubbed with 10% to 25% hydrochloric acid for 2 to 4 sections in the scrubbing stage, and each scrubbing time is 10 to 30 minutes. In the case of high impurity content, extending the scrubbing time can more effectively remove metal impurities such as iron and aluminum on the surface of the quartz sand, and improve the effect of subsequent flotation. After that, 4 to 6 water washings are performed. In the water washing step, pure water is used to avoid the impurities dissolved in the water from reattaching to the surface of the quartz sand particles and affecting the flotation effect. The water washing flow rate is controlled at 500 to 1000 L / h to ensure the cleaning effect. Then, a capture agent of 400 to 700 g / t of dodecylamine, sodium dodecyl sulfate and sodium oleate (combination ratio 3:2:1) is used to float the quartz sand under the condition of pH 2 to 4. Accurate capture agent ratio can more effectively target different impurities, improve the selectivity of flotation, reduce the waste of capture agent, and improve the separation effect of impurities. The capture agent is added in stages to avoid a large amount of one-time addition. The amount added in the initial flotation is controlled at 50%~60% of the total amount. The remaining capture agent is gradually added later to make the flotation process more uniform and stable, prevent excessive consumption of the capture agent in the initial stage, and ensure that the capture agent concentration is always at the optimal level during the entire flotation process. Immediately after flotation, multiple water washings are carried out, and deionized water is used to thoroughly remove the capture agent residues. The number of water washing sections is maintained at 4~6 sections, and the water flow rate is controlled at 500~1000L / h. Then, the quartz sand is dried at low temperature to maintain its integrity and purity.

[0020] Furthermore, the pH value can be 2-3. This range can more effectively enable the capture agent to act on the surface of impurities without causing excessive dissolution or damage to the quartz sand. By precisely controlling the pH value, the optimal activity of the capture agent can be ensured, the capture and separation of impurities can be promoted, and the flotation effect can be improved. At the same time, it is possible to avoid the pH value being too low or too high, which may cause damage to the quartz particles or poor flotation effect.

[0021] S08: The quartz sand is pickled with mixed acid, and the reactor temperature is maintained at 80~90℃; Preferably, in step S08, after flotation, the quartz sand is washed and dried, and then placed in a mixed acid for pickling, wherein the mixed acid is prepared by mixing HCl and HF in a volume ratio of 4-7:1-3. The concentration of HCl is 10%-20%, and the concentration of HF is 1%-5%. By controlling the acid concentration, efficient dissolution of impurities can be ensured, and excessive pickling can be avoided to affect the crystal structure of quartz sand. The pickling time is 2-6 hours, which ensures that the impurities in the quartz sand are fully dissolved, while avoiding unnecessary crystal damage and energy waste caused by excessive pickling.

[0022] S09: using hydrogen chloride gas to chlorinate and purify the quartz sand at 1100~1200℃; this step of chlorination purification mainly involves the reaction of hydrogen chloride gas with metal impurities to convert the impurities into volatile chlorides such as FeCl3.

[0023] Preferably, in step S09, after pickling, water washing and drying are performed, and then chlorination purification is performed, and the flow rate of hydrogen chloride gas is controlled at 0.5~1.5 L / min / kg of quartz sand. The chlorination purification time is controlled at 2~4h. If the time is too short, the metal impurities may not be completely chlorinated; if the time is too long, it may lead to increased corrosion to the equipment or damage to the crystal structure of the quartz sand. By accurately controlling the chlorination reaction time, it can be ensured that the impurities are completely converted into volatile chlorides, the purification effect is improved, and the waste of resources and material damage caused by insufficient reaction or excessive treatment are avoided. In the chlorination purification process, the volatilization amount of chloride can be monitored online (such as by mass spectrometer or infrared absorption spectrum), and when the volatiles reach a stable low value, the introduction of hydrogen chloride gas can be stopped. This can reduce the consumption of hydrogen chloride and prevent excessive chlorination of quartz sand.

[0024] S10: Dry the quartz sand particles to ensure that the material is in a dry state, and then use secondary magnetic separation on the quartz sand to obtain high-purity quartz sand. The secondary magnetic separation can appropriately reduce the magnetic field strength to within the range of 6000~8000GS. Because the amount of residual impurities after chlorination purification is small, a higher magnetic field strength may damage the surface of the quartz sand particles. By reducing the magnetic field strength, trace magnetic impurities can be effectively removed, while reducing damage to quartz sand particles and maintaining their integrity and quality. According to the content of residual impurities in the sand particles, the processing time of the secondary magnetic separation is controlled at 1~2 hours, which is similar to the time of the primary magnetic separation, but can be adjusted appropriately according to actual needs.

[0025] In summary, the present invention has the following beneficial effects: (1) The present invention systematically removes metal impurities and non-metallic impurities in the ore through multiple steps. In S01 and S02, ores with high impurity content (mica, feldspar) are screened out in advance through coarse crushing and screening, reducing the interference of impurities on subsequent processes. Such pretreatment ensures that the quartz ore has a low impurity content in the subsequent fine crushing and flotation process, avoids increasing the difficulty of subsequent processing due to excessive impurities, and helps to improve production efficiency. Then there are acid leaching, roasting and water quenching, flotation, pickling and chlorination purification, which can effectively remove common impurities such as iron, aluminum, titanium, mica, feldspar, etc. in the ore. Through multiple acid treatments and high-temperature chlorination purification, it is ensured that impurities are converted into volatile compounds and completely removed, significantly improving the purity of quartz sand.

[0026] (2) The two magnetic separations in the present invention remove magnetic mineral impurities and iron filings and other contaminants in the quartz sand by precisely controlling the magnetic field strength and the magnetic separation time. In particular, the secondary magnetic separation further purifies the quartz sand after the chlorination purification to ensure that the produced quartz sand can meet the high purity standard. In conjunction with the use of an electromagnetic magnetic separator, the efficiency and stability of impurity removal are guaranteed. High-precision magnetic separation can also further remove extremely small amounts of magnetic impurities that may remain after chlorination in the secondary magnetic separation, so that the purity of the quartz sand can meet the requirements of high-end applications such as electronic grade and optical fiber grade.

[0027] (3) In the chlorination purification step of the present invention, hydrogen chloride gas reacts with residual metal impurities in quartz sand at a high temperature of 1100-1200°C to convert them into volatile chlorides such as FeCl3, which are finally volatilized to achieve deep removal of insoluble impurities. Precise control of gas flow rate and introduction time ensures complete volatilization of impurities and improves the chemical purity of quartz sand. This step provides a key guarantee for the purification effect of the entire process, allowing quartz sand to meet electronic grade, optical fiber grade and even higher application standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments in the records of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The process flow chart of preparing and processing high-purity quartz sand from quartz ore with high iron and aluminum content in an embodiment of the present invention; Figure 2 is the metal element content of the original ore in the embodiment of the present invention; Figure 3 is the content of metal elements after scrubbing in the embodiment of the present invention; Figure 4 is the metal element content after flotation in the embodiment of the present invention; Figure 5 is the content of metal elements after pickling in the embodiment of the present invention; Figure 6 It is the content of metal elements after chlorination purification in the embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a process for preparing and processing high-purity quartz sand from a quartz ore with high iron and aluminum content proposed by the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0031] like Figures 1 to 6 The process of producing high-purity quartz sand from a quartz ore with high iron and aluminum content is shown in the figure, and the specific steps are as follows: S01: Use jaw crusher to roughly crush the raw ore to obtain coarse ore with an average particle size of 1~5cm; Preferably, in step S01, the ore with a particle size greater than 5 cm after coarse crushing is returned to the jaw crusher for further coarse crushing, and the ore with a particle size less than 1 cm is collected as quartz crushed material for standby use.

[0032] Specifically, the ore after coarse crushing needs to be graded by screening equipment. The present invention adopts a vibrating screen or a multi-layer screening machine to ensure the accurate separation of ores of different particle sizes. Among them, through two layers of screens, ores larger than 5cm, 1~5cm and smaller than 1cm are screened separately to improve screening efficiency and accuracy. For ores with a particle size larger than 5cm screened out, an automatic return system is set to return them directly to the jaw crusher through a conveyor belt or an automatic hopper for cyclic crushing to reduce the need for manual operation and improve production efficiency. Ore particles smaller than 1cm are directly sent to storage or standby processes through a collection bin or a conveying system.

[0033] The invention uses particle size screening and cyclic crushing to return large-size ores to the jaw crusher for re-crushing in time, thus avoiding the impact of oversized particles in subsequent processes on processing quality. Ores smaller than 1 cm are directly collected for use, reducing redundant crushing steps, optimizing the entire process, and improving production capacity and efficiency.

[0034] S02: Screen the coarse ore and pick out the coarse ore with more impurities; Preferably, in step S02, the coarse ore with more impurities is a coarse ore with mica and feldspar content greater than 70%. Compared with quartz ore, mica and feldspar have obvious differences in color, gloss and texture. Mica ore usually has a relatively smooth surface, strong reflective properties, and is especially easy to identify under light. Compared with quartz, feldspar has more diverse colors and a rougher surface. Specifically, a high-precision visual recognition system (such as industrial cameras and image processing technology) is used to monitor the coarse ore online, and ores with higher impurity content are identified by visual features such as color, gloss, and shape, and are automatically separated. At the same time, impurities such as light mica and feldspar can also be further separated by air separation or density sorting. These minerals usually have a low density and can be effectively removed by airflow or hydraulic separation technology.

[0035] The present invention can significantly reduce the content of impurities such as aluminum and potassium in quartz sand by effectively removing high-impurity ores containing mica, feldspar, etc. in the early stage, ensuring that higher-purity quartz sand is produced in the subsequent process to meet industrial or electronic grade requirements. At the same time, it can greatly reduce the workload of subsequent processes (such as acid leaching, magnetic separation and chlorination purification), shorten the acid leaching time, reduce the consumption of acid and other reagents, and improve the processing efficiency and economy of subsequent processes.

[0036] S03: Acid leaching is performed on the coarse ore after screening, wherein the acid used for acid leaching is a mixed acid of hydrochloric acid, hydrofluoric acid and oxalic acid, and the acid leaching time is 24-72 hours, and then washed with pure water; During the acid leaching process, the temperature is controlled within the range of 40~50℃ to accelerate the reaction rate between the acid and impurities. Increasing the temperature can enhance the activity of the acid and shorten the reaction time, but too high a temperature may cause the destruction of the quartz crystal structure, so it should not exceed 50℃. To ensure that the acid is in full contact with the ore surface, continuous stirring or intermittent stirring can also be used during the acid leaching process. This can improve the reaction efficiency between the acid and impurities and promote the dissolution of metal ions. The post-acid leaching rinse step uses high-pressure pure water spraying to ensure that the acid and metal ions on the ore surface are completely removed to avoid the influence of residual acid on subsequent processes. Cleanliness can also be ensured by multi-stage rinsing.

[0037] Preferably, in step S03, the mixing ratio of hydrochloric acid, hydrofluoric acid and oxalic acid is 40-60:10-30:10-20. The hydrochloric acid is industrial hydrochloric acid with a concentration of 15%-25%. Based on the weight of the ore, the amount of hydrochloric acid used is 20-50 kg / ton of ore, the concentration of hydrofluoric acid is 5%-10%, the amount is 5-20 kg / ton of ore, and the concentration of oxalic acid is 5%-10%, the amount is 3-10 kg / ton of ore.

[0038] The present invention can effectively remove different types of impurities (such as iron, aluminum, calcium, titanium, etc.) by reasonably adjusting the ratio of hydrochloric acid, hydrofluoric acid and oxalic acid. Hydrochloric acid is mainly used to dissolve oxides such as iron and aluminum, hydrofluoric acid can dissolve silicate impurities, and oxalic acid is used to form insoluble complexes with metal impurities. The above components can effectively improve the impurity removal efficiency.

[0039] S04: roasting and water quenching the clean ore after acid leaching; Preferably, in step S04, the ore rinsed after acid leaching is sent to a roasting furnace at 800°C-1500°C for roasting for 2-5 hours. The ore is red when the roasting material is discharged. Specifically, when the ore reaches dark red or orange-red, the roasting can be considered complete. This is a sign that the temperature inside the quartz ore is uniform and the impurities have begun to loosen. Then the roasted quartz sand is placed in water for water quenching and rapidly cooled with cooling water. The temperature of the cooling water during the water quenching process is between 10°C and 25°C. The lower water temperature helps the quartz ore to cool down quickly during water quenching, thereby further cracking and falling off the impurities inside the ore. The water quenching time is controlled at 10-30 minutes until the ore is completely cooled. The water quenching process further breaks the gas-liquid inclusions and impurities inside the ore through rapid cooling, which facilitates the removal of impurities in the subsequent processing process. At the same time, water quenching can harden the quartz crystal and enhance its mechanical strength.

[0040] S05: After the roasted and water-quenched ore is finely crushed and sanded, wet vibrating screening is performed to obtain 60-160 mesh quartz sand particles; in wet vibrating screening, an appropriate amount of water flow helps to avoid adhesion of quartz sand particles and prevent clogging of the screen. The water flow is controlled within the range of 30-50 liters of water per ton of quartz sand to ensure the cleaning effect while avoiding waste of water resources.

[0041] Preferably, in step S05, the ore with a particle size greater than 60 mesh after fine crushing is returned for further fine crushing, and the ore with a particle size less than 160 mesh is collected as quartz fine material for standby use. The present invention adopts different screen levels for step-by-step screening to ensure that large particles above 60 mesh are returned for further crushing, and fine materials below 160 mesh are separated. Double-layer or multi-layer screens are specifically configured to accurately separate quartz sands of different particle size ranges. The configuration of multi-layer screens can improve the screening accuracy, prevent quartz sands of uneven particle sizes from entering subsequent processes, and improve the quality consistency of finished quartz sands. The return of larger particles for further crushing can increase the output rate of quartz sand fine materials.

[0042] S06: The obtained quartz sand particles are magnetically separated by an electromagnetic separator, and the background magnetic field strength of the electromagnetic separator is 8000GS; a multi-stage magnetic separation process is specifically adopted. The first magnetic separation removes the main magnetic impurities (such as iron filings, magnetic dust, etc.), and the second or subsequent magnetic separation further removes the residual trace magnetic impurities to ensure that the purity meets the requirements.

[0043] Preferably, in step S06, the magnetic separation time is 1-2 hours. The temperature of the magnetic separation environment is 20-30°C, and the humidity is maintained between 30% and 50%. This can reduce particle adhesion, avoid clogging of the magnetic separator, and help improve the magnetic separation efficiency, ensuring that magnetic impurities at each stage can be effectively removed.

[0044] S07: Use a single tank flotation machine to perform acid scrubbing and flotation operations on quartz sand particles; like Figure 3 and Figure 4 As shown, in step S07, the quartz sand particles are scrubbed with 10% to 25% hydrochloric acid for 2 to 4 sections in the scrubbing stage, and the scrubbing time for each section is 10 to 30 minutes. In the case of high impurity content, extending the scrubbing time can more effectively remove metal impurities such as iron and aluminum on the surface of the quartz sand, and improve the effect of subsequent flotation. Then, 4 to 6 water washings are performed. In the water washing steps, pure water is used to prevent impurities dissolved in the water from reattaching to the surface of the quartz sand particles and affecting the flotation effect. The water washing flow rate is controlled at 500 to 1000 L / h to ensure the cleaning effect. Then, a capture agent of 400 to 700 g / t of dodecylamine, sodium dodecyl sulfonate and sodium oleate (combination ratio 3:2:1) is used to float the quartz sand under the condition of pH 2 to 4. Accurate capture agent ratio can more effectively target different impurities, improve the selectivity of flotation, reduce the waste of capture agent, and improve the separation effect of impurities. The capture agent is added in stages to avoid a large amount of one-time addition. The amount added in the initial flotation is controlled at 50%~60% of the total amount. The remaining capture agent is gradually added later to make the flotation process more uniform and stable, prevent excessive consumption of the capture agent in the initial stage, and ensure that the capture agent concentration is always at the optimal level during the entire flotation process. Immediately after flotation, multiple water washings are carried out, and deionized water is used to thoroughly remove the capture agent residues. The number of water washing sections is maintained at 4~6 sections, and the water flow rate is controlled at 500~1000L / h. Then, the quartz sand is dried at low temperature to maintain its integrity and purity.

[0045] Furthermore, the pH value can be 2-3. This range can more effectively enable the capture agent to act on the surface of impurities without causing excessive dissolution or damage to the quartz sand. By precisely controlling the pH value, the optimal activity of the capture agent can be ensured, the capture and separation of impurities can be promoted, and the flotation effect can be improved. At the same time, it is possible to avoid the pH value being too low or too high, which may cause damage to the quartz particles or poor flotation effect.

[0046] S08: The quartz sand is pickled with mixed acid, and the reactor temperature is maintained at 80~90℃; like Figure 5 As shown, in step S08, after flotation, the quartz sand is washed and dried, and then placed in a mixed acid for pickling. The mixed acid is prepared by mixing HCl and HF in a volume ratio of 4-7:1-3. The concentration of HCl is 10%-20%, and the concentration of HF is 1%-5%. By controlling the acid concentration, it is possible to ensure efficient dissolution of impurities and avoid excessive pickling to affect the crystal structure of quartz sand. The pickling time is 2-6 hours to ensure that the impurities in the quartz sand are fully dissolved, while avoiding unnecessary crystal damage and energy waste caused by excessive pickling.

[0047] S09: using hydrogen chloride gas to chlorinate and purify the quartz sand at 1100~1200℃; this step of chlorination purification mainly involves the reaction of hydrogen chloride gas with metal impurities to convert the impurities into volatile chlorides such as FeCl3.

[0048] like Figure 6 As shown, in step S09, after pickling, water washing and drying are performed, and then chlorination purification is performed, and the flow rate of hydrogen chloride gas is controlled at 0.5~1.5 L / min / kg of quartz sand. The chlorination purification time is controlled at 2~4h. If the time is too short, the metal impurities may not be completely chlorinated; if the time is too long, it may lead to increased corrosion to the equipment or damage to the crystal structure of the quartz sand. By accurately controlling the chlorination reaction time, it can be ensured that the impurities are completely converted into volatile chlorides, the purification effect is improved, and the waste of resources and material damage caused by insufficient reaction or excessive treatment are avoided. During the chlorination purification process, the volatilization amount of chloride can be monitored online (such as by mass spectrometer or infrared absorption spectrum). When the volatiles reach a stable low value, the introduction of hydrogen chloride gas can be stopped. This can reduce the consumption of hydrogen chloride and prevent excessive chlorination of quartz sand.

[0049] S10: Dry the quartz sand particles to ensure that the material is in a dry state, and then use secondary magnetic separation on the quartz sand to obtain high-purity quartz sand. The secondary magnetic separation can appropriately reduce the magnetic field strength to within the range of 6000~8000GS. Because the amount of residual impurities after chlorination purification is small, a higher magnetic field strength may damage the surface of the quartz sand particles. By reducing the magnetic field strength, trace magnetic impurities can be effectively removed, while reducing damage to quartz sand particles and maintaining their integrity and quality. According to the content of residual impurities in the sand particles, the processing time of the secondary magnetic separation is controlled at 1~2 hours, which is similar to the time of the primary magnetic separation, but can be adjusted appropriately according to actual needs.

[0050] The present invention systematically removes metal impurities and non-metallic impurities in the ore through multiple steps. In S01 and S02, ores with high impurity content (mica, feldspar) are screened out in advance through coarse crushing and screening, reducing the interference of impurities on subsequent processes. Such pretreatment ensures that the quartz ore has less impurity content in the subsequent fine crushing and flotation process, avoids increasing the difficulty of subsequent processing due to excessive impurities, and helps to improve production efficiency. Then there are acid leaching, roasting and water quenching, flotation, pickling and chlorination purification, which can effectively remove common impurities such as iron, aluminum, titanium, mica, feldspar, etc. in the ore. Through multiple acid treatments and high-temperature chlorination purification, it is ensured that impurities are converted into volatile compounds and completely removed, significantly improving the purity of quartz sand.

[0051] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for producing high-purity quartz sand from quartz ore with high iron and aluminum content, characterized in that: The specific steps are as follows: S01: Use jaw crusher to roughly crush the raw ore to obtain coarse ore with an average particle size of 1~5cm; S02: Screen the coarse ore and pick out the coarse ore with more impurities; S03: Acid leaching is performed on the coarse ore after screening, wherein the acid used for acid leaching is a mixed acid of hydrochloric acid, hydrofluoric acid and oxalic acid, and the acid leaching time is 24-72 hours, and then washed with pure water; S04: roasting and water quenching the clean ore after acid leaching; S05: After the roasted and water-quenched ore is finely crushed and sanded, wet vibration screening is performed to obtain quartz sand particles of 60-160 mesh; S06: Using an electromagnetic separator to magnetically separate the obtained quartz sand particles, the background magnetic field strength of the electromagnetic separator is 8000GS; S07: Use a single tank flotation machine to perform acid scrubbing and flotation operations on quartz sand particles; S08: The quartz sand is pickled with mixed acid, and the reactor temperature is maintained at 80~90℃; S09: Using hydrogen chloride gas to chlorinate and purify quartz sand at 1100~1200℃; S10: Then, the quartz sand is subjected to secondary magnetic separation to obtain high-purity quartz sand.

2. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S01, the ore with a particle size greater than 5 cm after coarse crushing is returned to the jaw crusher for further coarse crushing, and the ore with a particle size less than 1 cm is collected as quartz crushed material for standby use.

3. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S02, the coarsely-crushed ore with more impurities is the coarsely-crushed ore with mica and feldspar content greater than 70%.

4. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S03, the mixing ratio of hydrochloric acid, hydrofluoric acid and oxalic acid is 40~60:10~30:10~20.

5. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S04, the cleaned ore after acid leaching is sent to a 800-1500°C roasting furnace for roasting for 2-5 hours. The ore is red when being roasted and then the roasted quartz sand is placed in water for quenching and rapidly cooled with cooling water.

6. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S05, the ore with a particle size greater than 60 mesh after fine crushing is returned for further fine crushing, and the ore with a particle size less than 160 mesh is collected as quartz fine material for standby use.

7. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S06, the magnetic separation time is 1 to 2 hours.

8. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S07, in the scrubbing stage, the quartz sand particles are scrubbed with 10% to 25% hydrochloric acid for 2 to 4 stages, and then washed with water for 4 to 6 stages. Then, a capture agent composed of 400 to 700 g / t of dodecylamine, sodium dodecyl sulfate and sodium oleate is used to float the quartz sand at a pH of 2 to 4.

9. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S08, after flotation, the product is washed and dried, and then placed in a mixed acid for pickling. The mixed acid is prepared by mixing HCl and HF in a volume ratio of 4-7:1-3.

10. The process for producing high-purity quartz sand from quartz ore with high iron and aluminum content according to claim 1, characterized in that: In step S09, after pickling, water washing and drying are performed, and then chlorination purification is performed, and the flow rate of hydrogen chloride gas is controlled at 0.5~1.5 L / min / kg of quartz sand.

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