Leaching equipment for high-concentration heavy metal contaminated soil and leaching method thereof

Abstract

The invention discloses leaching equipment for high-concentration heavy metal contaminated soil and a leaching method thereof. The leaching method comprises the following steps: (1) collecting of a soil sample; (2) composite leaching of the soil sample: weighing the soil sample, adding deionized water according to a water-soil ratio, placing the soil sample in leaching equipment for the high-concentration heavy metal contaminated soil at room temperature, leaching with water, then leaching with sodium carbonate, oscillating, filtering to obtain a supernatant, and measuring the concentration of residual hexavalent chromium in the soil after two times of leaching; (3) reducing and stabilizing treatment: adding a reducing and stabilizing agent for reducing and stabilizing treatment; (4) maintaining: adjusting the pH value, maintaining for one day, and measuring the hexavalent chromium content and the pH value of the initial soil, the washed soil and the reduced soil. The invention further provides leaching equipment for the high-concentration heavy metal contaminated soil, and the leaching equipment is matched with the leaching method. The leaching method and the leaching equipment can be matched for use to achieve a good soil chromium leaching removal effect.

Description

technical field [0001] The invention relates to the technical field of soil remediation production, in particular to a leaching device and a rinsing method for soil polluted by high-concentration heavy metals. Background technique [0002] Chromium salt is one of the main series products of inorganic chemical industry. It is widely used in chemical industry, metallurgy, prevention and machinery and other industries. About 15% of the products in my country's national economy are related to chromium salt. The traditional method of chromium salt production mainly adopts high-temperature roasting-water immersion-multi-stage evaporation crystallization process, the extraction rate of chromium salt is only about 75%, and 2.5-3.0t of chromium residue is discharged for every 1t of chromium salt product produced. 1.0% to 3.0% of water-soluble Na contained in chromium slag 2 CrO 4 and 1.0% to 1.5% acid-soluble CaCrO 4 It is the main component of environmental pollution. With the i...

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Problems solved by technology

Most of the current leaching equipment adopts a tank-like structure, which is difficult to use in large-scale sites due to the influence of the manufacturing process and processing volume, and is limited by the leaching mechanism and reaction conditions, and the treatment effect on high-concentration heavy metal-contaminated soil It is difficult to meet the requirements. Therefore, it is necessary to develop a compound leaching equipment with a large amount of single treatment, simple operation, and most importantly, a good chromium removal effect for soil contaminated with high concentrations of heavy metals.

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