Method of continuously purifying potassium nitrate in batch in waste generated by glass hardening process

Abstract

The invention relates to a method of continuously purifying potassium nitrate in batch in waste generated by a glass hardening process. The method mainly comprises the following steps: firstly, heating and melting the waste into waste liquor; then, purifying out potassium nitrate with different purities in batch from the waste liquor by utilizing multi-stage cooling with different rates, so that potassium nitrate can be recycled. The method has the advantages of being environment-friendly and capable of lowering cost.

Description

technical field [0001] The invention relates to a method for purifying waste, in particular to a method capable of effectively purifying potassium nitrate from waste containing potassium nitrate and sodium nitrate produced in a vitrification process. Background technique [0002] The general glass hardening process can be divided into physical hardening or chemical hardening. Among them, the chemical hardening process is mainly to immerse the sodium silicate glass to be strengthened in the potassium nitrate melt, and through the chemical ion exchange reaction, the sodium silicate glass will The sodium ions that make the glass structure less compact are replaced by potassium ions in the potassium nitrate melt, that is, the sodium ions are replaced by larger potassium ions to improve the strength of the glass surface. [0003] After a period of chemical ion exchange reaction, part of the potassium nitrate component in the molten liquid is gradually exchanged for sodium nitrate...

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Problems solved by technology

[0003] After a period of chemical ion exchange reaction, part of the potassium nitrate component in the molten liquid is gradually exchanged for sodium nitrate, and although the industrial pure potassium nitrate molten liquid originally contains a small amount of sodium ions, when the concentration of sodium nitrate increases to a certain For example, after the concentration of sodium nitrate in the reacted melt is increased by tens of times, the reacted melt can no longer undergo ion exchange reaction, so that the purpose of improving the surface strength of the glass cannot be achieved.

[0004] Therefore, even if the reacted melt still contains potassium nitrate, it can no longer be used in the chemical hardening process. Therefore, in order to reduce the cost slightly, the reacted melt is taken out by dilution, and pure potassium nitrate is added again It is very wasteful and not environmentally friendly. In addition, a large amount of pure potassium nitrate melt is required for each dilution, resulting in high manufacturing costs.

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