Method for removing impurities in quartz ore through cascade chloridizing roasting

Abstract

The invention relates to a method for removing impurities in quartz ore through cascade chloridizing roasting, and belongs to the technical field of quartz sand purification. The method comprises the following steps: crushing cleaned natural quartz ore, and carrying out ball milling to obtain quartz ore particles; the quartz ore particles are heated to 400-700 DEG C at a constant speed, HCl gas is introduced, and first-stage roasting is carried out for 2-3 h; heating the quartz ore particles roasted at the first stage to 800-1100 DEG C at a constant speed, introducing Cl2, roasting at the second stage for 2-3 hours, and cooling to room temperature at a constant speed; and adding the quartz ore particles roasted at the second stage into deionized water, stirring at room temperature, carrying out water leaching for 4-8 hours, carrying out solid-liquid separation, and drying to obtain the high-purity quartz particles. According to the method, the quartz ore particles are subjected to two-stage cascade chloridizing roasting, different inclusion impurities in the quartz ore are removed, the removal rates of the final impurities Fe, Al, Na and K can reach 99.92%, 71.52%, 80.19% and 85.79%, and the light transmittance can reach 90% or above.

Description

Technical Field

[0001] The invention relates to a method for removing impurities in quartz ore by step-by-step chlorination roasting, belonging to the technical field of quartz sand purification. Background Art

[0002] High-purity quartz sand is the basic material for high-tech industries such as semiconductor chips, solar cells, and optical fibers. Its output and quality determine the production scale and development speed of high-tech industries. Quartz is one of the most widely distributed minerals on the earth's surface, but unprocessed natural quartz ore contains impurities such as minerals and gas-liquid inclusions, which cannot meet the purity requirements of high-purity quartz sand. It requires a complex purification process to obtain high-purity quartz sand products.

[0003] The main components of inclusions are Fe, Al, K, and Na, which are high in content and widely distributed in quartz ores, and are difficult to remove. The roasting methods commonly used for quartz ore purification include microwave roasting, vacuum roasting, chlorination roasting, etc. Microwave roasting and vacuum roasting have a certain removal effect on gas-liquid inclusions, but for mineral inclusions, they need to be combined with wet leaching to be removed. Chlorination roasting has the advantages of high temperature and chlorination agent, which can effectively remove inclusion impurities, but different types of inclusion impurities have different explosive dissociation temperatures, chlorination reaction temperatures, and chlorination reaction difficulties, resulting in low removal rates and poor removal effects of inclusion impurities in chlorination roasting. Summary of the invention

[0004] Aiming at the problem that the existing chlorination roasting technology is difficult to remove impurities in quartz efficiently and deeply, the present invention proposes a method for removing impurities in quartz ore by step-by-step chlorination roasting, that is, according to the chlorination reaction characteristics of HCl, Cl2 and impurities containing Fe, Al, K and Na inclusions and the explosion law of inclusions, quartz ore particles are subjected to two-stage step-by-step chlorination roasting to remove impurities of different inclusions in the quartz ore, and finally the removal rates of the impurities Fe, Al, Na and K can reach 99.92%, 71.52%, 80.19% and 85.79%, and the light transmittance can reach more than 90%.

[0005] A method for removing impurities from quartz ore by step-by-step chlorination roasting, the specific steps are as follows:

[0006] (1) crushing the cleaned natural quartz ore, and then ball milling to obtain quartz ore particles;

[0007] (2) uniformly heating the quartz ore particles in step (1) to a temperature of 400-700° C. and introducing HCl gas to perform a first stage roasting for 2-3 hours;

[0008] (3) the quartz ore particles roasted in the first stage of step (2) are heated to a temperature of 800-1100° C. at a uniform rate and Cl2 is introduced, and then roasted in the second stage for 2-3 hours, and then cooled to room temperature at a uniform rate;

[0009] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 4 to 8 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles; the light transmittance of the high-purity quartz particles is more than 90%.

[0010] Preferably, the particle size of the quartz ore particles in step (1) is 45 to 160 meshes, and the light transmittance is 35 to 65%.

[0011] Preferably, the heating rate in step (2) is 6-10° C. / min, the HCl gas introduction rate is 400-800 mL / min, and the introduction time is 15-30 min.

[0012] More preferably, in step (2), a solid chlorinating agent is added to the quartz ore particles.

[0013] Preferably, the solid chlorinating agent is two or more of NaCl, KCl, CaCl2, MgCl2, and BaCl2.

[0014] More preferably, the total amount of the solid chlorinating agent added is 0.2-0.5% of the mass of the quartz ore particles, and the amount of each solid chlorinating agent added is not higher than 0.1% of the mass of the quartz ore particles.

[0015] Preferably, the heating rate in step (3) is 6 to 10°C / min, the Cl2 gas introduction rate is 200 to 600 mL / min, and the introduction time is 15 to 30 min.

[0016] Preferably, the cooling rate in step (3) is 5 to 15°C / min.

[0017] By adopting step-by-step chlorination roasting, HCl is used at a relatively low temperature to remove impurities in iron inclusions, and Cl2 is used at a high temperature to remove impurities in aluminum inclusions. Solid chlorinating agents can also be used to open the internal channels of quartz, thereby achieving efficient and deep removal of impurities in quartz ore. At the same time, the two concentrated bursting temperatures of gas-liquid inclusions are fully utilized, and two-stage roasting is carried out to cause the gas-liquid inclusions to burst in two stages, thereby achieving deep removal of gas-liquid inclusions.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention targets natural quartz ore and utilizes the chlorination reaction characteristics of different mineral inclusions to perform step-by-step chlorination roasting. The impurities in the iron inclusions are removed by HCl during roasting at a relatively low temperature, and the impurities in the aluminum inclusions are removed by Cl2 during roasting at a relatively high temperature.

[0020] (2) The present invention utilizes the characteristics of concentrated bursting of gas-liquid inclusions and performs roasting at two temperature points to expand the size range of the bursting of gas-liquid inclusions;

[0021] (3) The step-by-step chlorination roasting adopted in the present invention removes a large amount of iron impurities and part of the gas-liquid inclusions in the first step, and the Fe impurities are deeply removed in the second step. At the same time, the removal effect of Al impurities and gas-liquid inclusions is improved. After testing, the removal rates of Fe, Al, Na, and K can reach 99.92%, 71.52%, 80.19%, and 85.79%, respectively, and the transmittance can reach more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0024] The impurity contents in the natural quartz ore in the comparative examples and embodiments of the present invention are as follows: by mass percentage, Fe is 0.1339%, Al is 0.014%, Na is 0.027%, and K is 0.04%.

[0025] Comparative Example 1: A method for removing impurities from quartz ore by chlorination roasting, the specific steps are as follows:

[0026] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 45 to 60 meshes;

[0027] (2) The quartz ore particles in step (1) were heated to 500° C., 600° C., and 700° C. at a heating rate of 6° C. / min, and HCl gas was introduced at a rate of 400 mL / min for 15 min, followed by roasting for 2 h; and the mixture was cooled to room temperature at a cooling rate of 5° C. / min;

[0028] (3) adding the quartz ore particles roasted in step (2) into deionized water, stirring and soaking in water at room temperature for 6 hours, separating the solid and the liquid, and drying to obtain purified quartz particles;

[0029] The removal rate and transmittance of Fe, Al, Na, and K impurities in the purified quartz particle samples calcined at 400°C, 500°C, 600°C, and 700°C were analyzed, and the results are shown in Table 1;

[0030] Table 1 Removal rate and transmittance of Fe, Al, Na and K in purified quartz particles at different calcination temperatures

[0031]

[0032] As can be seen from Table 1, under the conditions of HCl introduction for 15 min, introduction rate of 400 mL / min, roasting for 2 h, and water immersion for 6 h, the overall roasting effect is optimal when the temperature is 600 °C. The removal rates of Fe, Al, Na, and K in quartz are 98.9%, 36.05%, 33.77%, and 29.66%, respectively, and the transmittance is 67.42%, but the removal rates of Al, Na, and K are all low.

[0033] Comparative Example 2: A method for removing impurities from quartz ore by chlorination roasting, the specific steps are as follows:

[0034] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore to a particle size of 45 to 160 mesh to obtain quartz ore particles;

[0035] (2) the quartz ore particles in step (1) were heated uniformly to 600° C. at a heating rate of 7° C. / min, and HCl gas was introduced at a rate of 500 mL / min for 15 min, 20 min, 25 min, and 30 min, respectively, and then roasted for 3 h; and the temperature was uniformly cooled to room temperature at a cooling rate of 7° C. / min;

[0036] (3) adding the quartz ore particles calcined in step (2) into deionized water, stirring and soaking in water at room temperature for 7 hours, separating the solid and the liquid, and drying to obtain purified quartz particles;

[0037] The removal rates and transmittances of Fe, Al, Na, and K impurities in the purified quartz particle samples with HCl gas introduction times of 15 min, 20 min, 25 min, and 30 min were analyzed, and the results are shown in Table 2.

[0038] Table 2 Removal rates and transmittances of Fe, Al, Na, and K in purified quartz particles at different HCl gas introduction times

[0039]

[0040] As can be seen from Table 2, under the conditions of calcination at 600°C for 3h and water immersion for 7h, the overall calcination effect is optimal when the HCl introduction time is 15min and the introduction rate is 500mL / min. The removal rates of Fe, Al, Na, and K in quartz are 98.83%, 37.25%, 45.02%, and 22.03%, and the transmittance is 66.85%, but the removal rates of Al, Na, and K are all low.

[0041] Example 1: A method for removing impurities from quartz ore by stepwise chlorination roasting (see Figure 1 ), the specific steps are as follows:

[0042] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 45 to 60 meshes;

[0043] (2) the quartz ore particles prepared in step (1) were heated uniformly at a heating rate of 8°C / min to a temperature of 600°C and HCl gas was introduced at a rate of 600 mL / min for 15 min, followed by first stage roasting for 2 h, and argon gas was introduced for evacuation;

[0044] (3) The quartz ore particles roasted in the first stage of step (2) were heated to 800°C, 900°C, 1000°C, and 1100°C at a heating rate of 8°C / min, and Cl2 gas was introduced at a rate of 200 mL / min for 15 min, and the second stage was roasted for 2 h, and then cooled to room temperature at a cooling rate of 8°C / min;

[0045] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 5 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles;

[0046] The removal rate and transmittance of Fe, Al, Na, and K impurities in the high-purity quartz particle samples with the second-stage calcination temperature and the introduction time of 800°C, 900°C, 1000°C, and 1100°C were analyzed, and the results are shown in Table 3;

[0047] Table 3 Removal rates and transmittances of Fe, Al, Na, and K in high-purity quartz particles at different calcination temperatures in the second stage

[0048]

[0049] It can be seen from Table 3 that under the conditions of the second-stage roasting time of 2h, Cl2 introduction time of 15min and water immersion of 8h, the roasting temperature is 900℃ and the overall effect is optimal. The removal rates of Fe, Al, K and Na in quartz are 99.92%, 71.52%, 80.19% and 85.79%, and the transmittance is 91.59%. It is determined that the optimal roasting temperature of the second stage of this embodiment is 900℃.

[0050] Example 2: A method for removing impurities from quartz ore by stepwise chlorination roasting (see Figure 1 ), the specific steps are as follows:

[0051] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 60 to 80 meshes;

[0052] (2) the quartz ore particles prepared in step (1) were heated uniformly to 400° C. at a heating rate of 9° C. / min and HCl gas was introduced at a rate of 700 mL / min for 20 min, followed by first-stage roasting for 2.5 h, and argon gas was introduced for evacuation;

[0053] (3) The quartz ore particles roasted in the first stage of step (2) were uniformly heated to 900°C at a heating rate of 9°C / min and Cl2 gas was introduced at a rate of 300 mL / min for 15 min, 20 min, 25 min, and 30 min, respectively, and the second stage was roasted for 3 h, and then uniformly cooled to room temperature at a cooling rate of 9°C / min;

[0054] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 4 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles;

[0055] The removal rate and transmittance of Fe, Al, Na, and K impurities in the high-purity quartz particle samples with the second-stage Cl2 gas introduction time of 15 min, 20 min, 25 min, and 30 min were analyzed, and the results are shown in Table 4;

[0056] Table 4 Removal rates and transmittances of Fe, Al, Na, and K in high-purity quartz particles at different Cl2 gas introduction times in the second stage

[0057]

[0058] As can be seen from Table 4, under the conditions of the second-stage calcination at 900°C for 2h and water immersion for 9h, the impurity removal effect is best when Cl2 is introduced for 15min, and the removal rates of Fe, Al, K, and Na are 99.81%, 70.36%, 79.86%, and 85.62%, respectively, and the transmittance is 90.23%. It is determined that the optimal time for Cl2 gas introduction in this embodiment is 15min.

[0059] Example 3: A method for removing impurities from quartz ore by stepwise chlorination roasting (see Figure 1 ), the specific steps are as follows:

[0060] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 60 to 80 meshes;

[0061] (2) the quartz ore particles and the solid chlorinating agent (a mixture of KCl and NaCl) of step (1) are uniformly mixed, and then the temperature is uniformly increased to 500° C. at a heating rate of 10° C. / min, and HCl gas is introduced at a rate of 800 mL / min for 25 min, and then the first stage of roasting is performed for 2.8 h, and argon gas is introduced for evacuation; based on the mass of the quartz ore particles as 100%, the total amount of the solid chlorinating agent added is 0.2%, of which KCl accounts for 0.1% of the mass of the quartz ore particles and NaCl accounts for 0.1% of the mass of the quartz ore particles;

[0062] (3) The quartz ore particles roasted in the first stage of step (2) were uniformly heated to 800°C at a heating rate of 10°C / min and Cl2 gas was introduced at a rate of 400 mL / min for 30 min, and the second stage was roasted for 3 h, and then uniformly cooled to room temperature at a cooling rate of 12°C / min;

[0063] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 6 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles;

[0064] The removal rates of Fe, Al, Na, and K impurities and the transmittance of the high-purity quartz particle samples in this embodiment were analyzed. The removal rates of Fe, Al, K, and Na in the high-purity quartz particle samples in this embodiment were 99.93%, 83.54%, -5.31%, and -15.2%, and the transmittance was 91.03%.

[0065] Example 4: A method for removing impurities from quartz ore by stepwise chlorination roasting (see Figure 1 ), the specific steps are as follows:

[0066] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 60 to 80 meshes;

[0067] (2) the quartz ore particles and the solid chlorinating agent (a mixture of CaCl2 and BaCl2) of step (1) are uniformly mixed, and then the temperature is uniformly increased to 650°C at a heating rate of 7°C / min, and HCl gas is introduced at a rate of 600 mL / min for 25 min, and then the first stage of roasting is performed for 3 h, and argon gas is introduced for evacuation; based on the mass of the quartz ore particles as 100%, the total amount of the solid chlorinating agent added is 0.3%, wherein KCl accounts for 0.1% of the mass of the quartz ore particles, NaCl accounts for 0.1% of the mass of the quartz ore particles, and BaCl2 accounts for 0.1% of the mass of the quartz ore particles;

[0068] (3) The quartz ore particles roasted in the first stage of step (2) were uniformly heated to 1000°C at a heating rate of 7°C / min and Cl2 gas was introduced at a rate of 500 mL / min for 25 min, and the second stage was roasted for 2.5 h, and then uniformly cooled to room temperature at a cooling rate of 13°C / min;

[0069] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 7 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles;

[0070] The impurity removal rates and transmittances of Fe, Al, Na, K, and Ba in the high-purity quartz particle sample of this embodiment were analyzed. The removal rates of Fe, Al, K, Na, Ba, and Ca in the high-purity quartz particle sample of this embodiment were 99.92%, 83.26%, 82.35%, 86.33%, -1.31%, and -8.33%, respectively, and the transmittance was 90.32%.

[0071] Example 5: A method for removing impurities from quartz ore by stepwise chlorination roasting (see Figure 1 ), the specific steps are as follows:

[0072] (1) crushing the cleaned natural quartz ore, and then ball-milling the quartz ore particles to a particle size of 80 to 100 meshes;

[0073] (2) the quartz ore particles in step (1) and a solid chlorinating agent (a mixture of CaCl2, MgCl2 and BaCl2) are uniformly mixed, and then the temperature is uniformly increased to 700°C at a heating rate of 10°C / min, and HCl gas is introduced at a rate of 700 mL / min for 25 min, and then the first stage of roasting is performed for 2.8 h, and argon gas is introduced for evacuation; based on the mass of the quartz ore particles as 100%, the total amount of the solid chlorinating agent added is 0.3%, wherein CaCl2 accounts for 0.1% of the mass of the quartz ore particles, MgCl2 accounts for 0.1% of the mass of the quartz ore particles, and BaCl2 accounts for 0.1% of the mass of the quartz ore particles;

[0074] (3) The quartz ore particles roasted in the first stage of step (2) were uniformly heated to 1000° C. at a heating rate of 10° C. / min and Cl2 gas was introduced at a rate of 600 mL / min for 30 min, and the second stage was roasted for 3 h, and then uniformly cooled to room temperature at a cooling rate of 15° C. / min;

[0075] (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 8 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles;

[0076] The impurity removal rates and transmittances of Fe, Al, Na, K, Ca, Mg, and Ba in the high-purity quartz particle sample of this embodiment were analyzed. The impurity removal rates of Fe, Al, K, Na, Ca, Mg, and Ba in the high-purity quartz particle sample of this embodiment were 99.96%, 83.11%, 86.96%, 81.02%, -9.65%, -14.36%, and -2.11%, respectively, and the transmittance was 91.12%.

[0077] The invention adopts a step-by-step chlorination roasting method to purify quartz ore. The step-by-step chlorination roasting process has a high removal rate for Fe, Al, K and Na impurities, and also has a good removal effect on gas-liquid inclusions. In the first stage of the step-by-step chlorination roasting, impurities containing Fe inclusions are effectively removed, and part of the gas-liquid inclusions are exploded. In the second stage, impurities containing Al, K and Na inclusions are effectively removed, and more gas-liquid inclusions are exploded.

[0078] It should be noted that the above implementation case only selects two-stage implementation cases from the step roasting for description, and does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for removing impurities from quartz ore by stepwise chlorination roasting, characterized in that: The specific steps are as follows: (1) crushing the cleaned natural quartz ore, and then ball milling to obtain quartz ore particles; (2) uniformly heating the quartz ore particles in step (1) to a temperature of 400-700° C. and introducing HCl gas to perform a first stage roasting for 2-3 hours; (3) the quartz ore particles roasted in the first stage of step (2) are heated to a temperature of 800-1100° C. at a uniform rate and Cl2 is introduced, and then roasted in the second stage for 2-3 hours, and then cooled to room temperature at a uniform rate; (4) adding the quartz ore particles roasted in the second stage of step (3) into deionized water, stirring and soaking in water at room temperature for 4 to 8 hours, separating the solid and the liquid, and drying to obtain high-purity quartz particles.

2. The method for removing impurities from quartz ore by step-chlorination roasting according to claim 1, wherein: The particle size of the quartz ore particles in step (1) is 45 to 160 meshes, and the light transmittance is 35 to 65%.

3. The method for removing impurities from quartz ore by step-chlorination roasting according to claim 1, characterized in that: The heating rate of step (2) is 6-10° C. / min, the HCl gas introduction rate is 400-800 mL / min, and the introduction time is 15-30 min.

4. The method for removing impurities from quartz ore by step-chlorination roasting according to claim 1, characterized in that: In step (2), a solid chlorinating agent is added to the quartz ore particles.

5. The method for removing impurities from quartz ore by step-chlorination roasting according to claim 4, characterized in that: The solid chlorinating agent is two or more of NaCl, KCl, CaCl2, MgCl2, and BaCl2.

6. The method for removing impurities from quartz ore by stepwise chlorination roasting according to claim 5, characterized in that: The total amount of solid chlorinating agent added is 0.2-0.5% of the mass of the quartz ore particles, and the amount of each solid chlorinating agent added is not higher than 0.1% of the mass of the quartz ore particles.

7. The method for removing impurities from quartz ore by stepwise chlorination roasting according to claim 1 or 4, characterized in that: The heating rate of step (3) is 6-10°C / min, the Cl2 gas introduction rate is 200-600L / min, and the introduction time is 15-30min.

8. The method for removing impurities from quartz ore by step-chlorination roasting according to claim 1 or 4, characterized in that: The cooling rate of step (3) is 5 to 15°C / min.

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