A method for concentrating and recycling polluted acid

Abstract

The invention discloses a contaminated acid concentrating and recycling method. The method comprises the following steps: adding a contaminated acid solution and a vulcanizing agent solution into a negative pressure reaction kettle according to an amount ratio of 1L:(10-30)g, reacting under the condition of 60-70 DEG C for 25-40 minutes, performing filter pressing on the reacted materials by using a filter press, and treating the filtrate in the next step; adding the filtrate and the vulcanizing agent solution into another negative pressure reaction kettle according to an amount ratio of 1L:(20-48)g, reacting at room temperature for 80-100 minutes, precipitating by using a thickener, performing filter pressing by using the filter press, treating the obtained contaminated acid filtrate by virtue of a dynamic wave scrubbing tower to remove lots of ions F<-1> and Cl<-1>, thereby obtaining the 50-60% industrial sulfuric acid. The contaminated acid is treated by combining two-stage vulcanization and evaporation and concentration, the heavy metals and arsenic are effectively removed by controlling the time and temperature during two-stage vulcanization, the sulfur and metal elements are comprehensively recycled, the cost is low, and the economic benefits are high.

Description

technical field [0001] The invention belongs to the field of metal smelting acid waste acid treatment, and in particular relates to a method for concentrating and recycling waste acid. Background technique [0002] In the process of non-ferrous metal smelting, a large amount of dirty acid wastewater generated by the acid production process usually contains As 3+ 、As 5+ 、Cu 2 + , Pb 2+ , Zn 2+ and other heavy metal ions and F — , Cl — , due to the high concentration of polluted acid and high concentration of heavy metals, valuable metals are transferred to the waste residue during the treatment process, which is difficult to recycle. At the same time, a large amount of hazardous waste is generated, which is easy to cause serious secondary pollution. [0003] At present, most smelting enterprises adopt sulfide-lime iron salt method, lime-iron salt method to treat dirty acid, sulfide to remove impurities, and lime milk neutralization method. These processes will consume ...

AI Technical Summary

Problems solved by technology

[0002] In the process of non-ferrous metal smelting, a large amount of dirty acid wastewater generated by the acid production process usually contains As 3+ 、As 5+ 、Cu 2 + , Pb 2+ , Zn 2+ and other heavy metal ions and F — , Cl — , due to the high concentration of polluted acid and high concentration of heavy metals, valuable metals are transferred to the waste residue during the treatment process, which is difficult to recycle. At the same time, a large amount of hazardous waste is generated, which is easy to cause serious secondary pollution

[0003] At present, most smelting enterprises adopt sulfide-lime iron salt method, lime-iron salt method to treat dirty acid, sulfide to remove impurities, and lime milk neutralization method. These processes will consume a large amount of lime resources and produce a large amount of gypsum slag, causing serious damage to the environment. pollution, waste of resources, and high production costs; now there is a dirty acid treatment process for sulfuration and impurity removal, but the removal efficiency of the toxic metal arsenic in the dirty acid is low, and the environmental protection requirements are not met; and sulfuration and impurities are rarely combined with Comprehensive treatment of acid recovery, low economic benefit