Fly ash melting vitrification pretreatment system and method

Abstract

The invention discloses a fly ash melting vitrification pretreatment system and method, and the system is characterized in that a material mixing unit is provided with a fly ash inlet, a leachate concentrated solution inlet, a binder inlet, a compounding agent inlet and a mixed material outlet, and the material mixing unit is internally provided with a stirrer; the leachate concentrated solution storage unit is provided with a leachate concentrated solution outlet which is connected with the leachate concentrated solution inlet of the material mixing unit; a fly ash outlet of the fly ash storage unit is connected with a fly ash inlet of the mixing unit; a compound agent outlet of the compound agent storage unit is connected with a compound agent inlet of the mixing unit; a binder outlet of the binder storage unit is connected with a binder inlet of the mixing unit; the forming unit is provided with a mixed material inlet and a formed material outlet, and the mixed material inlet is connected with the mixed material outlet of the mixing unit; the drying unit is provided with a formed material inlet and a dried formed material outlet, and the formed material inlet is connected with the formed material outlet of the forming unit. According to the system and the method, fly ash molded products meeting requirements can be prepared.

Description

technical field [0001] The invention relates to the field of garbage disposal, in particular to a system and method for pretreatment of fly ash melting and vitrification. Background technique [0002] Waste incineration, medical waste incineration and hazardous waste incineration have shown a good momentum of development in my country. Due to the thorough innocence of incineration and a high degree of reduction, it is considered to be an important direction for urban waste treatment in my country. Waste incineration will produce a large amount of fly ash, which is the powdery particulate matter collected after the waste incineration flue gas is purified by the bag filter. It is an inevitable product of waste incineration, accounting for about 3% to 5% of the total waste incineration. The components are oxides and calcium salts containing Si, Ca, Al, Fe, etc., and also contain a large amount of heavy metals adsorbed by activated carbon and highly toxic organic compounds such ...

AI Technical Summary

Problems solved by technology

However, the backspray of the leachate concentrate aggravates the corrosion of the furnace, causing related systems to fail to operate normally, and also increases the treatment cost of the flue gas purification system

[0004] Chinese patent application CN110345484A discloses a system for the co-processing of garbage fly ash and leachate. This scheme utilizes the residual heat of fly ash melting to evaporate the leachate concentrate, but this scheme does not carry out molding and compatibility pretreatment on fly ash. After the fly ash enters the melting furnace, it is easy to be drawn out under the action of negative pressure suction, increasing the pressure of the subsequent purification system, and the molten vitrification rate is difficult to meet the requirements

[0005] Chinese patent application CN106217925B discloses a method for pretreatment of waste incineration fly ash before melting. The leachate is directly mixed with the two materials of fly ash and extruded. Electric arc furnace raw materials, but the cold strength, hot strength and vitrification rate of molten products after forming are difficult to meet the requirements of current production standards

[0006] In the existing scheme of pretreatment of waste incineration fly ash before melting, only fly ash and leachate are directly co-processed, and the influence of material strength after molding on subsequent utilization is not fully considered

For example, due to the very weak viscosity of the leachate itself, the columnar electric arc furnace raw material after direct molding has many irregular sections, low strength, and is easy to pulverize, especially the thermal strength is very poor, and the effect is not ideal. At the same time, only extruding Forming the final raw material has the problems of low efficiency and high energy consumption; and the melting of fly ash needs to be carried out according to the requirements of vitrification. Compatibility of raw material components, only simple mixing and molding, can not meet the molten vitrification rate (national standard GB / T41015-2021 "Technical Requirements for Vitrification Treatment Products of Solid Waste" requires vitrification rate ≥ 85%)

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