Method for treating flue gas generated in valuable secondary material treatment process

Abstract

The invention provides a method for treating flue gas generated in a valuable secondary material treatment process. The method comprises the following steps: 1) pre-dedusting the flue gas; 2) carrying out controllable random cooling on the flue gas temperature, and carrying out semi-dry desulfurization by spraying quicklime powder and activated carbon powder; 3) recycling soot collected by a primary bag-type dust collector; 4) carrying out secondary combustion on the flue gas by adopting a heat accumulating type incinerator, spraying a urea solution into a combustion chamber, and carrying out denitration by adopting an SNCR method; 5) carrying out heat exchange on the subsequent flue gas and the flue gas discharged from the heat accumulating type incinerator, and raising the temperature of the flue gas entering the chimney to 120 DEG C or above; 6) quickly spraying activated carbon into the flue gas, so that the activated carbon and the flue gas are fully mixed, and removing activated carbon powder through a secondary bag-type dust collector; 7) performing secondary desulfurization by adopting a sodium hydroxide solution or a sodium carbonate solution; and 8) carrying out reinforced desulfurization supplement on the flue gas subjected to secondary desulfurization. According to the invention, high-efficiency, energy-saving, environment-friendly and ultra-clean emission can be realized.

Description

technical field [0001] The invention belongs to the technical field of environmental protection flue gas treatment, and in particular relates to a treatment method for flue gas generated during the disposal of valuable secondary materials. Background technique [0002] Valuable secondary materials such as copper-containing, nickel-containing sludge and electronic waste have complex components and contain a variety of metals and organic substances. During the treatment process, they face two major problems: environmental pollution and comprehensive recovery. The main treatment processes include pyrolysis and wet treatment. kind: [0003] Fire methods include traditional closed oxygen-enriched side-blown furnace method, rotary incinerator method, top-blown furnace method, etc. The treatment of flue gas generally adopts inclined flue, ash bucket, surface cooler using air heat exchange, cloth bag collection, etc. Dust, alkali method (calcium, sodium, magnesium, etc. as desulfur...

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Problems solved by technology

There is also a secondary combustion chamber in front of the inclined flue, which uses fuel to support combustion and raise the temperature to above 800°C for more than 2s to promote the decomposition of dioxins (PCDD / Fs), and then quench it to 200°C within 2s to prevent secondary combustion. Resynthesis of dioxin (PCDD / Fs) substances; although this can meet the basic discharge standards of dioxin (PCDD / Fs) substances, but the heat loss is large, not energy-saving and economical

[0004] The wet recovery method is to use inorganic strong acid, strong alkali and other media to leach valuable secondary materials such as copper and nickel sludge and electronic waste, so that valuable secondary materials such as copper and nickel sludge and electronic waste The vast majority of metals (including precious metals and base metals) in the process are dissolved and enter the liquid phase, and then the precious metals and other base metals are recovered from the liquid phase. The advantages are that there is less waste gas emission, and the residue after extracting the precious metals is easy to handle, but the consumption of chemical reagents Large amount, complex process, low comprehensive recovery level, corrosive and toxic leachate and residue, if not handled properly, it is easy to cause more serious secondary pollution

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