Method for safely and efficiently treating arsenic waste water generated from arsenic hydride production

Abstract

The invention relates to a method for safely and efficiently treating arsenic waste water generated from arsenic hydride production. The method comprises the steps of adding alkaline substance into the arsenic waste water, and neutralizing the waste water until the waste water is alkaline; adding oxidant into alkaline waste water, and oxidizing and transforming volatile arsenic hydride dissolved in the waste water into non-volatile arsenate AsO4<3->; adding metal ions M<n+> and forming a precipitate Mx(AsO4)y from the soluble arsenate AsO4<3->; adding a flocculating agent and an adsorbent, further reducing arsenic content in the waste water through adsorption and coprecipitation, filtering and collecting arsenic solid waste after the solid gets complete precipitation. Through the combination of physical and chemical methods, arsenic content in the waste water generated from arsenic hydride production is effectively reduced, and a great amount of virulent waste water is transformed into recycling industrial water; as arsenic solid waste collected from the treating process is small in size, the arsenic solid waste water can be safely and conveniently treated as the solid waste.

Description

technical field [0001] The invention relates to a method for safely and efficiently treating arsenic-containing wastewater in the production of arsenic, which uses a combination of physical and chemical methods to safely and efficiently treat the industrial wastewater generated in the industrialized production of arsenic, so that the content of arsenic in the wastewater can reach Levels that can continue to be recycled, thereby greatly reducing the discharge of toxic arsenic-containing wastewater. Background technique [0002] High-purity arsine (>99.9999%) is widely used in "N" type doping of epitaxial silicon in the semiconductor industry, silicon ion implantation, growth of high-end solar cells gallium arsenide (GaAs) thin films, and in III-V solid semiconductor lighting It is used in the growth of red and yellow LED epitaxial wafers and so on. In addition, arsine is also used as standard gas, calibration gas, etc. Therefore, it is of great significance to actively c...

AI Technical Summary

Problems solved by technology

The waste liquid generated in the preparation of arsine will lead to the uncontrolled release of arsine under the following conditions: 1) If the above reaction is not absolutely 100% complete, the trace amount of zinc arsenide in the reaction waste liquid will continue to react, continue to Produce highly toxic arsine, 2) arsine has a certain solubility in aqueous solution, arsine dissolved in wastewater will cause arsine to be released when the temperature changes or when it is stirred, causing safety problems

In addition, almost all arsenic-containing substances are highly toxic chemicals, and the wastewater generated in the preparation of arsenic may also contain other trace arsenic chemical components, which brings potential safety hazards

Therefore, a large amount of wastewater generated in the preparation of arsine must be strictly detoxified to avoid serious casualties and environmental pollution.