A rinse process for deep cleaning of natural quartz after purification
By employing a three-step cleaning process and ultrasonic treatment, the problem of residual contaminants after acid washing of quartz sand is solved, achieving a highly efficient and water-saving deep cleaning effect and improving the purity and applicability of quartz sand.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG RUNYOU NEW MATERIAL TECH CO LTD
- Filing Date
- 2025-11-14
- Publication Date
- 2026-07-24
AI Technical Summary
The residual pollutants after acid washing of existing quartz sand are difficult to remove completely, resulting in substandard product purity and huge water consumption, which affects applications in high-tech fields.
A three-step cleaning process is adopted, combining ultrasound and cleaning solutions of different concentrations, including deionized water, anhydrous ethanol, hydrogen peroxide and hydrofluoric acid, with ultrasonic treatment at different frequencies, to gradually remove stubborn impurities from the surface of quartz sand.
It achieves deep cleaning of quartz sand, improves product purity and cleaning efficiency, reduces water consumption, and is suitable for industrial production.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of quartz sand purification and industrial cleaning technology, specifically relating to a deep cleaning rinsing process for purified natural quartz. Background Technology
[0002] In the wet chemical purification process of quartz sand, acid leaching (or pickling) is the core step. The acid reacts with impurities such as metal oxides on the surface of the quartz sand to generate soluble salts, thus significantly improving the purity of the quartz sand. However, after the acid leaching process, a large amount of residual acid and reacted metal salts (such as Fe) remain on the surface of the quartz sand and in the gaps between particles. 3+ Al 3+ Ca 2+ The residues include salts and other insoluble suspended solids. If these residues are not thoroughly removed, they will not only contaminate the final product, leading to substandard purity, but may also form difficult-to-remove secondary stains during subsequent high-temperature drying processes, severely impacting the application value of quartz sand in high-tech fields (such as photovoltaics, semiconductors, and high-end glass). Therefore, the rinsing process after acid washing is a crucial bridge connecting chemical purification and the final product, and its effectiveness directly determines the success or failure of the purification process and the stability of product quality.
[0003] In existing technologies, such as CN115465866A, a high-purity quartz sand refining process and high-purity quartz sand are described. The quartz sand is repeatedly rinsed with distilled water until neutral after acid washing. This process is very simple, but the residual strong acid (such as HF or HCl) has a high concentration and is trapped between the quartz sand particles. Neutralization is achieved solely through water dilution, and the mass transfer between water and quartz sand particles relies mainly on natural diffusion, which is slow and may require several times, or even tens of times, the volume of ultrapure water. CN115771897A describes a continuous acid washing purification method for quartz sand. After acid washing, the quartz sand is submerged in 32-36 cm of clean water, stirred three times for 35-40 minutes each time, and then allowed to stand for 40 minutes. This is also a typical large-volume water dilution strategy. The supernatant is directly discharged after settling. This method of separation is ineffective, as fine-grained quartz sand and light impurities are difficult to settle completely and will be lost with the wastewater, resulting in a reduced product yield. Furthermore, the fine contaminants that are not removed can easily re-contaminate the quartz sand during the next water addition.
[0004] The aforementioned processes cannot dissolve or destroy the structure of the solid deposits produced after acid leaching, and they consume a huge amount of water. Therefore, developing a deep rinsing process that can efficiently treat stubborn residues and save water has become a pressing technical challenge in this field. Summary of the Invention
[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a deep cleaning rinsing process for natural quartz after purification, which aims to efficiently and thoroughly remove residual contaminants from the surface of quartz sand after acid washing, and finally obtain quartz sand products with ultra-high cleanliness.
[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0007] A deep-cleaning rinsing process for purified natural quartz includes the following steps:
[0008] The acid-washed quartz sand was cleaned three times in a fixed sequence in a cleaning medium tank, and ultrasonic waves were applied simultaneously during the cleaning process.
[0009] The three cleaning media are:
[0010] First cleaning: Clean with a mixture of deionized water and anhydrous ethanol;
[0011] Second cleaning: Cleaning is performed using a mixed cleaning solution consisting of deionized water, hydrogen peroxide, and hydrofluoric acid;
[0012] Third cleaning: Final rinse with deionized water.
[0013] Preferably, ultrasonic waves are applied during the first cleaning process. The frequency of the ultrasonic waves is 40 kHz to 80 kHz, the ultrasonic action time is 3 to 5 minutes, and the process is followed by a 5-minute resting period.
[0014] Preferably, in the first cleaning, the volume ratio of deionized water to anhydrous ethanol is 1:(0.1~0.25), and the volume ratio of cleaning solution to quartz sand is (2~2.5):1.
[0015] Preferably, ultrasonic waves are applied during the second cleaning process. The frequency of the ultrasonic waves is 80 kHz to 120 kHz, and an intermittent ultrasonic method is used, that is, a single ultrasonic wave lasts for 3 to 5 minutes and then there is a 5-minute interval. The total cleaning time is 45 to 60 minutes, and the device is left to stand for 5 minutes after the cleaning is completed.
[0016] Preferably, the volume ratio of the mixed cleaning solution in the second cleaning is deionized water: hydrogen peroxide: hydrofluoric acid = 1 : (1~1.5) : (1.5~2), and the volume ratio of the cleaning solution to the quartz sand is (2~2.5):1.
[0017] Preferably, the solution is heated during the second cleaning process to a temperature of 70-85°C.
[0018] Preferably, ultrasonic waves are applied during the third cleaning process. The frequency of the ultrasonic waves is 40 kHz to 80 kHz, the ultrasonic action time is 3 to 5 minutes, and the process is followed by a 5-minute resting period.
[0019] Preferably, after each cleaning, the quartz sand is subjected to solid-liquid separation, and the separated quartz sand is transferred to the next cleaning medium.
[0020] Preferably, the endpoint of the third cleaning is that the resistivity of the effluent is ≥5MΩ.
[0021] Preferably, after the third washing, the quartz sand is dehydrated and dried at a temperature of 120~180℃ for 30~60 minutes, so that the final moisture content of the quartz sand is less than 2%.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0023] (1) Achieved deep and precise cleaning: This invention innovatively adopts a three-step cleaning scheme. The first step uses anhydrous ethanol to change the surface tension of the solution and, in conjunction with ultrasound, efficiently removes loose impurities and organic reagent residues from the flotation process from the surface of quartz sand particles; the second step utilizes the strong oxidizing properties of hydrogen peroxide and the micro-etching properties of dilute hydrofluoric acid, under the enhancement of ultrasound and heating, to thoroughly remove stubborn metal impurities remaining on the surface, which is the key to achieving "deep cleaning"; the third step uses high-purity water to thoroughly wash away the residue. The three steps have clear functions and work synergistically, resulting in a cleaning effect far exceeding that of traditional single water washing.
[0024] (2) Significantly improved cleaning efficiency: Multi-frequency ultrasonic waves are introduced throughout the process for assistance. Different frequencies of ultrasonic waves are used in different steps, making the process more targeted: low frequency (40~80kHz) has a strong cavitation effect, which is conducive to the removal of large particles of impurities; medium and high frequency (80~120kHz) has a finer cavitation effect, which is conducive to the cleaning of surface micro-areas and the promotion of chemical reactions. The introduction of ultrasonic waves greatly accelerates the mass transfer process and shortens the cleaning time.
[0025] (3) Extremely high product purity and quality: By setting the final rinsing water resistivity ≥5MΩ as the endpoint indicator, quantitative and precise control of product cleanliness is achieved, ensuring the stability and ultra-high purity of batch products. The final low-temperature slow drying process also avoids product cracking or secondary contamination that may be caused by rapid drying.
[0026] (4) The process is highly controllable and suitable for industrial production: The parameters (concentration, temperature, time, power) of each step of this process can be precisely controlled. The process is clear and easy to achieve automated and continuous production, and has good prospects for industrial application. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] The present invention will be further described below with reference to specific embodiments.
[0029] To maintain the consistency of the experiment, the natural quartz ore used in Examples 1 to 5 below all came from the same batch of stable quality quartz ore from a certain quartz mine in Xinjiang, with a quartz content of about 75-85% in the raw ore.
[0030] Example 1
[0031] Raw material preparation: Take a certain amount of natural quartz sand (particle size range of 80-160 mesh) that has been pretreated by crushing, magnetic separation and conventional mixed acid washing, as the raw material to be washed.
[0032] First cleaning (water-alcohol cleaning): In an ultrasonic cleaning tank, add 200L of deionized water, then slowly add 30L of anhydrous ethanol, stirring gently to form a mixed cleaning solution with a deionized water to anhydrous ethanol volume ratio of 100:15 (approximately 1:0.15). Add quartz sand to the cleaning tank, ensuring the liquid completely submerges the sand; the cleaning solution to quartz sand volume ratio is approximately 2.5:1. Turn on the ultrasonic generator, set the frequency to 40 kHz, and ultrasonically treat for 5 minutes. Then turn off the ultrasonic generator and let it stand for another 5 minutes. After the quartz sand has completely settled, drain the upper waste liquid. Transfer the quartz sand to a dedicated draining container for solid-liquid separation.
[0033] Second cleaning (deep cleaning): In the ultrasonic cleaning tank, first add 200 L of deionized water as the base solution. While continuously stirring and cooling, slowly add 30 L of 30% hydrogen peroxide (H2O2), followed by 40 L of 40% hydrofluoric acid (HF). The final cleaning solution has a volume ratio of approximately H2O : H2O2 : HF = 100 : 15 : 20. Add all the quartz sand from the first cleaning to this mixed cleaning solution (the volume ratio of cleaning solution to quartz sand is approximately 2.5:1). Turn on the heating device to raise and maintain the cleaning solution temperature at 85℃. Simultaneously, turn on the ultrasonic cleaning system, set the frequency to 100kHz, and operate in intermittent mode: ultrasonic treatment for 5 minutes, then stop for 5 minutes, which constitutes one cycle. Repeat this cycle, with a total cleaning time of 60 minutes. After cleaning, turn off the ultrasonic cleaning system and heating, and let it stand for 5 minutes. The upper layer of waste acid is discharged, and the quartz sand is transferred to an acid-resistant draining container to complete the solid-liquid separation.
[0034] Third cleaning (final rinsing): Add sufficient deionized water to the ultrasonic cleaning tank to completely submerge the quartz sand. Turn on the ultrasonic cleaner, set the frequency to 40 kHz, and ultrasonically treat for 5 minutes, then let it stand for 5 minutes. Drain the supernatant. Repeat this "water addition-ultrasonic treatment-standing-draining" process, and monitor the resistivity value of the drain outlet online. When the resistivity of the drained water stably reaches ≥5 MΩ, the rinsing is considered complete.
[0035] The quartz sand was removed and dehydrated using a centrifuge. The dehydrated wet quartz sand was then sent to a rotary dryer and dried at 150°C for 45 minutes to obtain high-purity quartz sand. The test showed that the water content of the high-purity quartz sand was <1.5%.
[0036] Example 2
[0037] In this embodiment, the volume ratio of deionized water to anhydrous ethanol in the first cleaning was 1:0.1, and the volume ratio of cleaning solution to quartz sand was 2:1. In the second cleaning, the ratio of deionized water:hydrogen peroxide:hydrofluoric acid was 100:10:15, and the volume ratio of cleaning solution to quartz sand was 2:1. The cleaning solution temperature was maintained at 70°C. Other steps were consistent with the experimental steps and methods of Example 1.
[0038] Example 3
[0039] In this embodiment, during the first cleaning process, when preparing the mixed cleaning solution, the volume ratio of deionized water to anhydrous ethanol was 1:0.25, and the other steps were consistent with the experimental steps and methods of Example 1.
[0040] Example 4
[0041] In this embodiment, the ratio of deionized water:hydrogen peroxide:hydrofluoric acid in the second cleaning solution is 100:15:15, and the temperature of the cleaning solution is maintained at 80°C. The other steps are consistent with the experimental steps and methods of Example 1.
[0042] Example 5
[0043] In this embodiment, the ultrasonic mode was changed during the second cleaning process. A higher frequency of 120 kHz and a shorter interval were used, with ultrasonication lasting 3 minutes and a 5-minute interval. The other steps remained consistent with the experimental steps and methods of Example 1.
[0044] Comparative Example 1
[0045] In the second cleaning process, the volume ratio of the mixed solution was deionized water: hydrogen peroxide: hydrofluoric acid = 100:12:8. The other steps were consistent with the experimental steps and methods of Example 1.
[0046] Comparative Example 2
[0047] During the second cleaning process, the volume ratio of the mixed solution was deionized water: hydrogen peroxide: hydrofluoric acid = 100: 5: 17. The other steps were consistent with the experimental steps and methods of Example 1.
[0048] Comparative Example 3
[0049] During the second cleaning process, the heating device was not turned on, and ultrasonic cleaning was performed at room temperature (approximately 25°C). The other steps were consistent with the experimental steps and methods of Example 1.
[0050] Comparative Example 4
[0051] In the second cleaning process, the 5-minute interval step was omitted, and continuous ultrasound at a frequency of 100 kHz for 60 minutes was used. The other steps were consistent with the experimental steps and methods in Example 1.
[0052] Comparative Example 5
[0053] In the second cleaning process, the cleaning solution was changed to a solution composed of deionized water and hydrofluoric acid in a ratio of 100:20. The other steps remained consistent with the experimental steps and methods of Example 1.
[0054] Comparative Example 6
[0055] In the second cleaning process, the cleaning solution was changed to a solution composed of deionized water and hydrogen peroxide in a ratio of 100:15. The other steps remained consistent with the experimental steps and methods of Example 1.
[0056] Sample Analysis
[0057] The impurity content of the quartz sand products prepared in the examples and comparative examples was characterized using inductively coupled plasma optical emission spectrometry (ICP-OES), and the results are shown in Tables 1 and 2.
[0058] Table 1 shows the impurity content (ppm) in the quartz sand products from the examples.
[0059] project Example 1 Example 2 Example 3 Example 4 Example 5 Al 5.45 6.02 5.55 5.42 5.84 B 0.13 0.14 0.14 0.15 0.14 Ba 0.04 0.05 0.05 0.03 0.04 Ca 1.08 1.47 0.97 1.33 1.35 Cr 0.02 0.03 0.02 0.02 0.02 Cu 0.01 0.01 0.01 0.01 0.01 Fe 0.61 0.77 0.56 0.57 0.69 Ge 0.33 0.37 0.31 0.34 0.34 K 0.15 0.27 0.15 0.18 0.22 Li 0.29 0.47 0.31 0.35 0.27 Mg 0.07 0.13 0.07 0.07 0.09 Mn 0.01 0.01 0.02 0.01 0.02 Na 0.32 0.56 0.28 0.35 0.37 Ni 0.05 0.04 0.04 0.05 0.06 P 0.43 0.68 0.43 0.72 0.62 Ti 2.23 2.29 2.11 2.41 2.35 Zr 0.03 0.12 0.04 0.03 0.02 ∑ 11.25 13.43 11.06 12.04 12.45
[0060] Table 2 shows the impurity content (ppm) in the quartz sand products of the comparative examples.
[0061] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Al 13.16 11.30 9.58 9.95 15.53 12.67 B 0.41 0.77 0.53 0.56 0.35 0.63 Ba 0.05 0.05 0.03 0.04 0.07 0.06 Ca 3.58 2.84 2.29 1.77 4.85 4.42 Cr 0.03 0.03 0.02 0.02 0.03 0.03 Cu 0.27 0.13 0.14 0.21 0.23 0.28 Fe 3.41 2.88 2.35 2.77 3.58 3.83 Ge 0.32 0.35 0.37 0.37 0.34 0.33 K 0.73 0.58 0.62 0.65 0.71 0.73 Li 0.42 0.44 0.33 0.37 0.41 0.42 Mg 0.29 0.56 0.32 0.23 0.32 0.45 Mn 0.01 0.02 0.01 0.01 0.02 0.02 Na 2.34 3.53 2.95 2.87 3.64 3.24 Ni 0.06 0.04 0.06 0.05 0.06 0.07 P 0.66 0.65 0.76 0.71 0.69 0.68 Ti 2.49 2.88 3.11 3.05 2.78 2.68 Zr 0.04 0.05 0.02 0.03 0.05 0.02 ∑ 28.27 27.1 23.49 23.66 33.66 30.56
[0062] ICP-OES analysis results from the examples and comparative examples confirm that by fully adopting the technical solution of this invention (including the specific ratio of cleaning fluid, heating, and intermittent ultrasonic processes), ultra-high purity quartz sand products can be stably obtained, with significant effects on removing residual elements such as Al, Fe, Na, K, and Ca. Any deviation from key parameters will lead to a significant decrease in product purity, which fully demonstrates the inventiveness and practicality of the technical solution of this invention.
[0063] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A deep-cleaning rinsing process for purified natural quartz, characterized in that, Includes the following steps: Step 1: Place the acid-washed quartz sand into a cleaning medium tank containing a mixed cleaning solution of deionized water and anhydrous ethanol for cleaning, and apply ultrasonic waves during the cleaning process. Step 2: Place the quartz sand cleaned in Step 1 into a cleaning medium tank containing a mixed cleaning solution of deionized water, hydrogen peroxide and hydrofluoric acid for cleaning. Ultrasonic waves are applied during the cleaning process. Step 3: Rinse the quartz sand cleaned in Step 2 in a deionized water cleaning medium tank to remove acid residue and achieve deep cleaning. Ultrasonic waves are applied during the cleaning process. In step two, the mixed cleaning solution is heated to a temperature of 70-85℃; the ultrasonic frequency is 80 kHz-120 kHz, the duration of a single ultrasonic treatment is 3-5 min, and the ultrasonic treatment is continued after a 5 min interval, with a cleaning time of 45-60 min, followed by a 5 min settling time; the volume ratio of deionized water, hydrogen peroxide and hydrofluoric acid is 1:(1-1.5):(1.5-2), and the volume ratio of the mixed cleaning solution to quartz sand is (2-2.5):
1.
2. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, In step one, the frequency of the ultrasound is 40 kHz to 80 kHz, the ultrasound treatment time is 3 to 5 minutes, and the resting time after completion is 5 minutes.
3. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, In step one, the volume ratio of deionized water to anhydrous ethanol is 1:(0.1~0.25), and the volume ratio of the mixed cleaning solution to quartz sand is (2~2.5):
1.
4. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, In step three, the frequency of the ultrasound is 40 kHz to 80 kHz, the ultrasound treatment time is 3 to 5 minutes, and the resting time after completion is 5 minutes.
5. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, After each cleaning, the quartz sand is separated into solid and liquid components, and the separated quartz sand is transferred to the next cleaning medium tank.
6. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, The endpoint of step three is that the resistivity of the water is ≥5MΩ.
7. The rinsing process for deep cleaning of purified natural quartz according to claim 1, characterized in that, After the third step of cleaning is completed, the quartz sand is dehydrated and dried. The drying temperature is 120~180℃ and the time is 30~60min, so that the final moisture content of the quartz sand is less than 2%.