SU1692651A1 - Method for purifying quartz material - Google Patents

Abstract

The invention relates to the enrichment of minerals and m. used for the needs of fiber optics, microelectronics, etc. The goal is to improve the quality of cleaning while improving the environmental friendliness of the process. The feedstock is crushed in an electrohydraulic crushing unit. For manufacturing the chamber, electrodes, and the classifier of the installation, magnetically mild steel is used for magnetism. The material is then subjected to wet magnetic separation in a strong field to remove magnetic particles. The tension in the working gap of the magnetic separator is supported from 1000 to 2000 kA / m. After that, the material is subjected to chemical treatment. The chemical treatment is carried out in a solution of oxalic acid with a concentration of from 1.5 to 4.0 wt.% At a temperature of from 50 to 90 ° C for a time period of at least 30 minutes. Then the material is washed. Washing is carried out with distilled water in a counter flow apparatus. The speed of the wash water is maintained from 0.2 to 1 m / s. The material is then subjected to sterile drying, classification and intermediate transport operations. 1 Il.

Description

ABOUT

Yu

N) С СЛ

The invention relates to the production technology of high-purity silica glass and can be used for the needs of fiber optics, microelectronics, etc.

The purpose of the invention is to improve the quality of the markup while improving the eco-friendly process.

The drawing shows the implementation of the method.

In the method of cleaning quartz material, which includes electrohydraulic crushing, wet magnetic separation, chemical treatment, washing, drying and classification, for the working parts of the electrohydraulic crushing unit, magnetically mild steel is used in a wet field; A working gap of 1000–2000 kA / m, chemical treatment is carried out in a solution of oxalic acid with a concentration of 1.5–4.0 May. % with for at least 30 minutes, rinsing is carried out with distilled water in an anti-drip device at washing water speeds of 0.2–1 m / s. When crushing, the charge is contaminated with the material from which the electrohydraulic crushing unit is made. The amount of contaminants in the grinding stage in the method is even slightly higher, however, the indicators of the final cleaning depth are much higher, satisfy the requirements imposed on the charge, and correspond to the level of harmful impurities in the feedstock. The latter can be achieved by applying magnetic separation in a strong field, chemical treatment in oxalic acid and removal of the smallest particles at the washing stage, as well as by excluding the introduction of contaminants when transporting the material in a moist state. The operation of wet magnetic separation in a strong field with a tension in the working gap of more than 1000 kA / m makes it possible to remove almost completely particles from low-carbon magnetically soft steels of small size (up to 3 microns). A much deeper removal of the metal indicates that the metal particles introduced into the charge during the electrohydraulic crushing stage are small and therefore most fully removed at the highest possible field strengths (up to 2000 kA / m).

Since magnetic separation quite completely removes the introduced metal in the form of individual particles, the task of the chemical treatment operation is to remove contaminants from the surface of the charge particles (i.e., actually only to remove the thinnestheatry films from the surface of quartz formed at the crushing stage)

To solve this problem, less active low-concentrated and low-volatile acid solutions, for example oxalic acid solution, were used as a reagent. It dissolves iron and its oxides well due to the high complex-forming ability of oxalic acid. The use of this reagent makes it possible to create an economically pure and continuous chemical treatment process. By performing this operation in a countercurrent column apparatus, it is easy to organize multiple circulation of the reagent and thereby reduce its losses to a minimum. The acid solution is lost only at the outlet of the chemical processing apparatus and does not exceed 15–20 kg of reagent for every 100 kg mixed with wash water and then used as a transport liquid

to supply the charge to the washing operation. Excess transport fluid with oxalic acid content less than 0.1 wt.% Is discharged into acidic effluent where it is easily neutralized with a solution of water. When working with this reagent, it is also possible to significantly reduce the content of harmful acid vapors in the air.

To ensure a continuous process, the rate of dissolution of the metal or

its oxides should be sufficiently high, since the contact time of the phases is limited. To increase the contact time of the phases, liquid overloading of the charge with the help of a reagent is provided; in addition, it promotes faster removal of reaction products from the contact surface and an increase in the cleaning rate. Intermediate transshipment and transportation of grain are elements of the chemical

rubbing that is often used in enrichment processes. For the same purpose, the possibility of installing an ultrasonic radiator is provided in the middle part of the countercurrent columns. Phase contact time

With such an organization, the process should be at least 30 minutes.

To create cleaner processes, it is necessary to strive for lower concentrations of acid in

solution. This leads to a decrease in the amount of acid in the discharged waters, and the amount of harmful vapors in the air. The washing operation is carried out to remove the reagent from the surface of the charge.

and for leaching the smallest particles of less than 3 microns in size and carried out with distilled water in a similar countercurrent apparatus. Moreover, all the wash water is mixed with the reagent and

5 is used as an intermediate transport fluid.

The washed wash is transported using an ejector with distilled water to the filter belt cone-thickener where the dewatering operation is carried out.

The last drying operation is carried out in a special shaft dryer.

5 The method of preparing the charge allows transportation of the material from the hydraulic crushing unit to the drying facility of the material in a humidified state. The latter significantly reduces the likelihood of foreign inclusions and harmful impurities in the final product.

Example. Artificial quartz crystals and high-purity glass obtained by vapor-phase synthesis (artificial glass obtained by vapor-phase synthesis is processed for the purpose of reuse in the production of quartz crucibles) are used as raw materials for the production of the charge.

The feedstock with the help of a vibrating channel 1 is fed to an electrohydraulic crushing unit. From where the charge with a particle size of up to 0.5 mm, the hydroejector 3 is overloaded into a settling tank 4. At the crushing stage, the maximum contamination of the raw material with metal to (20-30) wt% occurs. Subsequent cleaning with a magnetic field separator 5 with a weak field makes it possible to remove the largest ferromagnetic particles. Next, the hydroejector 6 loads the receiving tank of the magnetic separator 7 with a strong field. At this stage, with a voltage of more than 1000 kA / m, it is possible to bring the amount of iron to (6-8) 10 wt.%. The separator is unloaded through a vibration separator 8 of the liquid and enters an intermediate transport vessel 9, from where a special ejector 10 charges the mixture with a reagent into the receiving tank 11 of the chemical treatment plant 12. The chemical treatment operation allows to bring the amount of iron to (1-3) wt.%. The processed mixture is unloaded at the vibrating separator 13 of the reagent and with the transport fluid using the ejector 14 and fed to the receiving tank 15 of the washing column 16. The washing operation allows washing the mixture from the reagent and bring the iron content to (0.5-1) 10 wt. % due to the removal of the smallest metal particles. The overload of the charge from under the column is carried out using an ejector 17. The suspension is fed to a belt filter 18, where it is dehydrated to a moisture content of 4-6 wt.%. Then the wet material enters the sterile shaft dryer 19, where it is finally dried. The final operation is classification 20. Centrifugal pumps 21 are designed to create a transport fluid head. The container 22 allows reuse of the transport fluid and the reagent.

The application of the method allows you to create continuous processes for the preparation of the charge and organize the inter-operational transportation of the grains in a moist state without the human being. The use of low aggressive low concentrated and low volatile reagents significantly reduces reagent consumption, reduces emissions of harmful substances, which helps to improve working conditions.

Claims (1)

Claims A method for cleaning a quartz material, including electrohydraulic crushing, wet magnetic separation, chemical treatment, washing, drying and classification, characterized in that, in order to improve the quality of cleaning while improving the environmentally friendly process, for working parts of the installation, electrohydraulic crushing uses low-carbon magnet steel, wet magnetic separation is carried out in a field with a strength in the working gap of 1000-2000 kA / m, chemical treatment is carried out in a solution of oxalic acid with a concentration of 1.5-4.0 wt.% at 50-90 ° C for a time period of at least 30 minutes, and rinsing is carried out with distilled water in a countercurrent apparatus at speeds of washing water 0.2  m / s R