Utilizing method of zinc-containing dust ash of steel plant

Abstract

The invention relates to a utilizing method for producing zinc oxide products by utilizing zinc-containing dust ash of a steel plant and recycling ferric carbon for returning to smelting. Zinc in the dust ash is leached by use of an ammonia method; materials which have the zinc content greater than 15% and contain non-vulcanized zinc are added for increasing the concentration of a zinc solution; leachate is purified, cleaned and subjected to ammonia distilling, and zinc oxide is prepared after electrolytic zinc preparation or zinc deposition; and original dust ash tailings or screened dust ash tailings are sent into a blast furnace for smelting, or a conventional pyrogenic process is adopted for recycling ferric carbon from the original dust ash tailings or the screened dust ash tailings, and collected secondary zinc oxide dust ash is used for the front end leaching, so that the zinc concentration of the leachate is increased. The utilizing method can be applicable to dust ash, with the zinc content as lower as 4% or even lower, of the steel plant; by use of a conventional method, the zinc extraction rate and the removing rate of harmful substances including alkali metal, fluorine and chlorine are both above 90%; the dust ash tailing recovery process is high in equipment adaptability, and appropriate treatment processes can be chosen according to existing equipment; and efficiency is high, the environment is protected, and comprehensive cyclic utilization of the zinc-containing dust ash is achieved.

Description

technical field [0001] The invention relates to a method for producing zinc oxide products from zinc-containing soot in iron and steel plants and recovering iron carbon for efficient utilization. Background technique [0002] At present, soot ash from steel mills (including blast furnace ash, converter ash, electric furnace ash), also known as soot storage ash, will produce 35-90kg of soot ash for every ton of steel produced. This soot ash generally contains 15-30% iron. %, containing 4-5% silicon oxide, 5-22% zinc, 25-55% combustible fixed carbon (C), 2-5% calcium oxide, 1-2% magnesium oxide, titanium, vanadium and alkali metals, etc. . Under normal conditions, the sintered ore is generally used as a raw material for sintering, and is recycled in the steel plant. With the enrichment of the cycle, the zinc load into the furnace is getting higher and higher, which seriously affects the normal operation of the blast furnace. [0003] The current methods to limit the zinc loa...

AI Technical Summary

Problems solved by technology

The first method is not an economical and effective method to reduce the zinc load of blast furnace, but also brings environmental pollution

The second is to enrich zinc into the tailings, but the three products of iron concentrate, carbon concentrate, and tailings are out of balance, and high iron and carbon resources are still lost

[0008] 1. Due to the low zinc content in the dust storage ash of steel mills (generally Zn% = 5-22), the zinc concentration in the leaching solution is low, the consumption of leaching agents is large, and the cost is high, which cannot be afforded by the enterprise

[0009] 2. Due to the complex composition of impurities, the production can only be ordinary active zinc oxide products and the pass rate is low, the product price is low and the economic benefit is poor

[0010] 3. When leaching by conventional means, the leaching rate of soot ash and zinc is low, the recovery rate is low, the recovery of iron and carbon resources has not formed a complete chain, and the value of soot ash has not been reflected

[0011] 4. Heating and evaporating the zinc-ammonia complex solution to recover ammonia requires a lot of heat, high cost, and cannot produce zinc

[0012] Patent No. CN201210358206.2 "A method for producing high-purity nano-zinc oxide using soot from steel mills", CN201210357961.9 "A method for producing high-purity nano-zinc oxide using ammonia decarburization of soot from steel mills", CN201210357962.3 " A method for producing high-purity nano-zinc oxide using the ammonia method of soot and ash in steel mills", CN201210358096. Method for producing high-purity zinc oxide from soot ash", CN201210358030.0 "A method for producing high-purity zinc oxide by ammonia decarburization of soot and ash from a steel plant" and a series of ammonia processes, simply using wet process, due to zinc The soot ash content is generally low, the simple wet leaching either has a low zinc content in the solution, or the leaching process is complicated and repeated and the leaching rate is low, which ultimately leads to high production costs, and the return of iron carbon in the tailings of soot and ash after leaching The use of steel plants is also mentioned in one sentence, and a practical and feasible solution has not been determined

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