No-waste utilization method of heavy metal-contained sludge

Abstract

The invention provides a no-waste utilization method of heavy metal-contained sludge. The heavy metal-contained sludge includes copper, chromium and iron elements; and the no-waste utilization method comprises the following steps: (S1) acidophilia microorganisms are added in the heavy metal-contained sludge for biological leaching treatment and solid-liquid separation to prepare leaching slag and leaching liquid; (S2) hydroxamic extracting agent solution with selectivity on copper is adopted to extract the leaching liquid prepared in the step (S1) to prepare copper-contained extracting liquid capable of singly recovering copper and raffinate A; (S3) sulfite is added in the raffinate A to adjust the solution pH value of not more than 2.0, is heated, and is added in phosphate to prepare chromium phosphate precipitates capable of singly recovering chromium; and (S4) remained solution B after chromium precipitation in the step (S3) is treated by an oxidizing agent; the solution pH value is adjusted within 1.0-1.5; and sodium sulfate is added under the condition of 80-95 DEG C to prepare sodium jarosit capable of singly recovering iron. The no-waste utilization method has the advantages of comprehensive sludge utilization, high utilization rate and no pollution.

Description

technical field [0001] The invention belongs to the technical field of solid waste disposal, in particular to a non-waste utilization method for sludge containing heavy metals. Background technique [0002] Facing the rapid development of my country's industry and the acceleration of urbanization, the amount of toxic and harmful solid waste produced has increased rapidly. The resulting safe disposal of "bulk solid waste" in the field of industrial production is very severe. Except for traditional industries In addition to harmful heavy metal tailings, coal gangue, smelting slag, phosphogypsum, red mud and calcium carbide slag, it also includes heavy metal-containing sludge from industrial sources, whose annual discharge has reached 23.06 million tons, and contains more than 1,000 tons of various heavy metals. Ton. [0003] At present, there are many treatment methods for sludge containing heavy metals, such as resource utilization, solidification landfill, incineration dispos...

AI Technical Summary

Problems solved by technology

Among them, there are two types of resource utilization: pyrolysis and wet disposal: the pyrolysis process consumes a lot of energy, causes serious pollution, and the resource utilization rate is not high. Iron and chromium cannot be used, and are only suitable for materials with high copper and nickel. , belongs to the phase-out technology; and the wet treatment and disposal technology has the following defects: (1) the disposal scale is limited, the process is incomplete, and the comprehensive utilization rate is low. If the waste water, waste gas and waste residue in the production process are not properly disposed of, it is easy to cause Secondary pollution; (2) The treatment process is simple, and the adaptability to raw materials is poor, and only the sludge with high nickel and copper content can be processed and recycled; (3) Most of them can only produce crude products, and the economic benefits are low

[0004] Patent CN101643243 discloses a method for recovering copper, nickel, chromium, zinc, and iron from electroplating sludge. The main products include fine chemical products such as copper sulfate, basic nickel carbonate, chromium salt, zinc sulfate, and ferric chloride. High utilization rate of metal resources, less process waste residue, complete detoxification and other significant advantages, but the two-step leaching acid consumption in this method is high. In addition, sulfide precipitation is used to separate zinc and nickel from ferrochrome, and the sulfide precipitate is hot-pressed into copper-containing The solution of zinc, nickel, and copper is extracted in the next step, nickel is precipitated by carbonic acid, and the tail liquid is concentrated and crystallized to prepare zinc sulfate. The ferrochrome solution is oxidized to hexavalent chromium by hot pressing, and the iron is oxidized to iron red slag under pressure. Dissolve with ferric chloride acid solution, concentrate and crystallize into ferric chloride. This method requires high equipment conditions, and repeated leaching-precipitation-hot-press leaching leads to lengthy process links. Trivalent chromium is oxidized to hexavalent chromium, not only Chromium salt solution requires further deep iron removal, and iron red slag entrained with hexavalent chromium can easily pollute downstream products. Although the leached slag meets the toxic leaching standard, there are often some heavy metals left in traditional acid, which will still be dissolved when the environment changes. risks of

[0005] Usually the industrial sources of heavy metal-containing sludge are mainly aimed at the comprehensive utilization of copper, nickel, zinc, and iron, but the quality of the recycled products obtained is difficult to control, and new waste residue, waste water, and waste gas are often generated during the treatment process, although some Metals have been comprehensively utilized, but pollution problems still exist, and even cause greater environmental pollution

At present, there is no technology that can reduce the amount of sludge and make it harmless, and at the same time separate copper, chromium, iron, zinc, nickel and other metals in sludge to obtain corresponding metal or metal salt products

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