Method for solid-liquid separation of waste incineration fly ash water washing slurry

Abstract

The invention discloses a method for solid-liquid separation of a waste incineration fly ash water washing slurry. The method comprises the following steps: 1, adding water to waste incineration fly ash to be processed, and carrying out stirring water washing to obtain a primary fly ash water washing slurry to be processed by adopting two horizontal screw discharge decanter centrifuges; 2, carrying out primary centrifuge separation on the primary fly ash water washing slurry by adopting a first horizontal screw discharge decanter centrifuge to obtain solid fly ash and a secondary fly ash water washing slurry; 3, simultaneously pumping a flocculating agent and the secondary fly ash water washing slurry into a second horizontal screw discharge decanter centrifuge; and 4, carrying out secondary centrifuge separation on the flocculated secondary fly ash water washing slurry by adopting a second horizontal screw discharge decanter centrifuge to obtain a solid phase and a liquid phase. The method can effectively remove salt substances in the waste incineration fly ash water washing slurry, and controls the fly ash loss amount of the waste incineration fly ash water washing slurry in an allowed loss amount range.

Description

technical field [0001] The invention belongs to the field of waste treatment, in particular to a method for solid-liquid separation of waste incineration fly ash washing slurry. Background technique [0002] Waste incineration fly ash is the dust collected by the flue gas dust collection system of waste incineration power plants. Waste incineration fly ash is not a chemically inert substance. It contains Cd, Pb, Zn, Cr and other harmful heavy metals and salts that can be leached by water. Under the influence of acid rain and other factors, heavy metals will gradually leach out in acidic environment and re-enter the environment, polluting groundwater sources and endangering human beings. [0003] At present, the treatment methods for waste incineration fly ash mainly include melting treatment, cement solidification, chemical stabilization treatment, etc. Melting treatment has the advantages of high volume reduction rate, stable slag properties, and no heavy metals, but this ...

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Problems solved by technology

[0003] At present, the treatment methods for waste incineration fly ash mainly include melting treatment, cement solidification, chemical stabilization treatment, etc. Melting treatment has the advantages of high volume reduction rate, stable slag properties, and no heavy metals, but this process consumes a lot of energy. At the same time, the volatile heavy metal elements such as Pb, Cd, and Zn need to undergo strict follow-up flue gas treatment, so the treatment cost is very high; the chemical stabilization treatment has the advantages of simple treatment process, low equipment investment, and small final treatment volume, but it will Produce high-concentration inorganic salt wastewater, which requires further treatment; cement solidification method is a relatively common treatment method at present, and fly ash can be used to make cement, which can also be used to recycle resources while treating waste, but the side effects of fly ash will affect The quality of cement, so in the pretreatment process of cement kiln co-processing fly ash, the salt substances in fly ash must be removed first, in the process of solid-liquid separation of fly ash washing slurry, in order to ensure the solid-liquid separation effect, It is necessary to remove the salts in the slurry phase of the fly ash and at the same time to ensure that the content of the salts in the solid phase is as low as possible. However, the existing solid-liquid separation treatment method has an unsatisfactory separation effect and cannot meet the above requirements