Method for recovering and purifying boron carbide from sapphire grinding wastes

A technology for grinding waste and sapphire, applied in chemical instruments and methods, carbon compounds, inorganic chemistry, etc., can solve the problems of volatile organic matter, low purity of boron carbide, unattainable, etc., and achieve the effect of reducing pollutant emissions

Active Publication Date: 2018-04-13
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The boron carbide recovery rate of this technical method reaches more than 80%, but the recovered boron carbide is not high in purity, especially a small amount of silicon carbide mixed in the slurry is not removed, and a large amount of organic matter is used in the process, which is volatile, and the process is lengthy and difficult to operate. industrial application
[0006] In addition, the grinding section of domestic sapphire processing enterprises does not strictly recycle waste abrasives in sections, but directly mixes them together, which results in different impurities mixed in by different manufacturers or different grinding sections, and the content varies greatly; Physical classification has been unable to completely remove impurity powder, such as entrained silicon carbide powder, because its physical and chemical properties are close to those of boron carbide, physical separation technology is more difficult to remove

Method used

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  • Method for recovering and purifying boron carbide from sapphire grinding wastes
  • Method for recovering and purifying boron carbide from sapphire grinding wastes
  • Method for recovering and purifying boron carbide from sapphire grinding wastes

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Embodiment 1

[0052] The grinding waste of a sapphire glass cover in Nanjing was used as the grinding waste of sapphire.

[0053] Because the sapphire grinding waste is in the form of mixed slurry, it can be filtered and dried at 100°C for 6 hours, and then sampled to detect its chemical composition. The results are shown in Table 1.

[0054] Table 1 Main composition of sapphire grinding waste

[0055]

[0056]

[0057] The method for recovering and purifying boron carbide from sapphire grinding waste in this embodiment will be described in detail below.

[0058] First, pass the sapphire grinding waste through a 200-mesh standard sieve to remove large particles of sand and stones, and then filter and dry; then, use a magnetic separation belt to remove iron impurities; the third step, use concentrated hydrochloric acid with a volume ratio of 1:1 Mix it with concentrated nitric acid to prepare an acidizing medium, add the dried sapphire grinding waste after removing iron impurities int...

Embodiment 2

[0066] The mixed grinding waste from a new material processing factory in Changzhou was used as the sapphire grinding waste.

[0067] Because the sapphire grinding waste is in the form of mixed slurry, it can be filtered and dried at 100°C for 6 hours, and then sampled to detect its chemical composition. The results are shown in Table 3.

[0068] Table 3 Main composition of sapphire grinding waste

[0069]

[0070] The method for recovering and purifying boron carbide from sapphire grinding waste in this embodiment will be described in detail below.

[0071] First, pass the sapphire grinding waste through a 200-mesh standard sieve to remove large particles of sand and stones, and then filter and dry; then, use a magnetic separation belt to remove iron impurities; the third step, use concentrated hydrochloric acid and concentrated nitric acid as the acidification medium , together with the dried sapphire grinding waste after removing iron impurities, was added to the acidif...

Embodiment 3

[0079] A waste abrasive from a sapphire processing enterprise in Chongqing was used as sapphire grinding waste.

[0080] Because the sapphire grinding waste is in the form of mixed slurry and mixed with other irrelevant impurities, it can be sieved with a 200-mesh standard sieve to remove large particles of impurities and fibers, and then dry the undersize at 100°C for 10 hours , sampling and testing chemical composition, the results are shown in Table 5.

[0081] Table 5 Main composition of sapphire grinding waste

[0082]

[0083] The method for recovering and purifying boron carbide from sapphire grinding waste in this embodiment will be described in detail below.

[0084] First, the sapphire grinding waste is passed through a 200-mesh standard sieve to remove large particles of sand, fibers, plastics and other sundries, then filter and dry; then, use a magnetic separation belt to remove iron impurities; the third step is to use a volume ratio of 1: Mix 1 concentrated ...

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Abstract

The invention discloses a method for recovering and purifying boron carbide from sapphire grinding wastes. The method comprises the following steps: S1, screening sapphire grinding wastes by a 200-mesh sieve to obtain a magnetic separation raw material; S2, carrying out magnetic separation on the magnetic separation raw material to remove iron impurities, so as to obtain an acid-soluble raw material; S3, placing the acid-soluble raw material in an acidification medium for acid dissolution to remove siliceous impurities, and obtaining a hydrothermal raw material through first-time solid-liquidseparation; S4, mixing the hydrothermal raw material with an alkaline solution, carrying out a hydrothermal reaction for 1-20h at 150-300 DEG C, and obtaining a hydrothermal product through second-time solid-liquid separation; and S5, carrying out water dissolution, third-time solid-liquid separation and drying on the hydrothermal product to obtain recovered boron carbide. According to the methodfor recovering and purifying boron carbide from the sapphire grinding wastes, provided by the invention, the recovery of boron carbide ultra-fine powder in the sapphire grinding wastes is realized, resources and energy consumption are greatly saved, the recovered boron carbide obtained through recovery meets an abrasive-grade requirement, and can be directly used, and the recovery rate of the boron carbide ultra-fine powder reaches 96% or more.

Description

technical field [0001] The invention belongs to the technical field of recycling grinding waste, and in particular relates to a method for recovering and purifying boron carbide from sapphire grinding waste. Background technique [0002] Boron carbide has a hard black shiny crystal, the hardness is lower than industrial diamond, but higher than silicon carbide; compared with most pottery, boron carbide is less brittle, has strong chemical resistance, and is not corroded by hot hydrogen fluoride and nitric acid. Soluble in molten alkali, insoluble in water and acid. Boron carbide is the third hardest substance after diamond and cubic boron nitride, and its price is relatively cheap, so it is widely used in the grinding and polishing process of high-hard materials such as sapphire glass coverslips. [0003] When the sapphire wafer is used as the LED substrate, the smoothness of the surface is very high, and it must be ultra-smooth and non-damaging. The quality of the device m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/991
Inventor 彭正军祝增虎诸葛芹李法强贾国凤上官雪慧杨国威吴康
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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