Method for precipitating and separating arsenic from waste acid wastewater

Abstract

The invention discloses a method for precipitating and separating arsenic from waste acid wastewater. The method comprises the following steps: pumping the waste acid wastewater into an acidic solution reactor, adding pyroantimonate according to a liquid-to-solid ratio of 4-10mL:1g, heating to 45-60DEG C, reacting for 15-20min, pumping the obtained reaction solution to a filter press, carrying out press filtration, allowing the obtained arsenic removal filtrate to flow to an acid and valuable metal recovery process, adding arsenic-supported pyroantimonate filter residues into an alkaline solution reactor according to a solid-to-liquid ratio of 1g:3-8mL, introducing air, heating to 78-90DEG C, stirring and reacting for 60-100min, pumping the obtained reaction solution to the filter press, carrying out press filtration, allowing the obtained press-filtered arsenic-rich filtrate to flow to a process for preparing arsenic trioxide and other arsenic products, and returning the arsenic removed pyroantimonate filter residues to the acidic solution reactor. The method has the following advantages: pyroantimonate has a good arsenic removal effect as an arsenic removal medicine; arsenic removal pyroantimonate can be reused, so the treatment cost is low; and the amount of generated dangerous solid wastes is small, so no secondary pollution is realized.

Description

technical field [0001] The invention relates to purification treatment and comprehensive utilization technology of polluted acid wastewater, in particular to a method for precipitating and separating arsenic from polluted acid wastewater. Background technique [0002] Arsenic is a sulfur-loving element, and it mainly exists in ores such as copper, lead, tin, zinc, and gold in the form of sulfide in the earth's crust, such as orpiment (As 2 S 3 ), realgar (As 4 S 4 ), arsenopyrite (FeAsS), arsenopyrite (Cu 3 AsS 4 ), arsenite (Cu 12 As 4 S 13 )Wait. The most common valence states of arsenic are -3, +3 and +5, the compounds with -3 and +3 valence are reducing, and the compounds with +5 valence are oxidizing. The most important compound of arsenic is arsenic trioxide (As 2 0 3 ) and arsenic pentoxide (As 2 0 5 ), both of these compounds decompose in a strong base to produce arsenite and arsenate, respectively. In the process of pyrometallurgy of copper, lead, tin,...

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Problems solved by technology

However, due to the characteristics of high acidity, high arsenic content, many types of heavy metals (including copper, zinc, lead, tin, etc.) It is necessary to build a special slag yard, which consumes a lot of slag yard maintenance costs every year

Due to the addition of a large amount of neutralizing agents, the hardness of the effluent water is too high and it is

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