Treatment method and device for secondary zinc oxide dust

Abstract

The invention discloses a treatment method and device for secondary zinc oxide dust. The treatment method comprises the following steps that S1, the secondary zinc oxide dust and water are mixed to prepare slurry, and the pH is adjusted to be 4.3-6.5; S2, rotary hearth furnace flue gas and the slurry are fed into a desulfurizing tower to be desulfurized, and a mixed solution and desulfurized gas are obtained; S3, the mixed solution is fed into an oxidation pond, air is introduced for oxidation treatment, then dilute sulphuric acid is added, and filtrate and a lead sulfate filter cake are obtained after filtering; and S4, the pH of the filtrate is adjusted to be 1.2-1.4, zinc powder is added, a zinc sulfate solution is obtained, and a zinc ingot is obtained after the zinc sulfate solution is electrolyzed. According to the treatment method, the secondary zinc oxide dust is adopted as an absorbent to fix SO2 in the flue gas, then metal zinc is obtained through the processes of oxidation,filtering, purification, electrodeposition and the like, the cost of secondary zinc oxide zinc extraction and flue gas treatment can be reduced, the problem that a desulfurized product is difficult totreat is solved, and the resource utilization of secondary zinc oxide is achieved.

Description

technical field [0001] The invention relates to a technology for treating zinc-containing dust in the field of metallurgy, in particular to a method and device for treating sub-zinc oxide dust. Background technique [0002] Iron and steel plants and smelters produce a large amount of dust and flue gas every year, and the flue gas contains SO 2 , the calcium method and ammonia method are mainly used to treat low-concentration SO-containing 2 Flue gas, but most of them have desulfurization products that are difficult to handle, and even belong to secondary pollution of heavy metals; dust mainly includes Gallo gas mud, electric furnace dust, converter secondary dust, dust sludge, fuming furnace dust collection and rotary kiln bag dust, etc. ; The above-mentioned dust is rich in elements such as zinc, lead, iron, silicon, etc., and has been piled up near iron and steel plants and smelters for a long time without effective treatment. It not only takes up a lot of land, but also ...

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Problems solved by technology

[0002] Iron and steel plants and smelters produce a large amount of dust and flue gas every year, and the flue gas contains SO 2 , the calcium method and ammonia method are mainly used to treat low-concentration SO-containing 2 Flue gas, but most of them have desulfurization products that are difficult to handle, and even belong to secondary pollution of heavy metals; dust mainly includes Gallo gas mud, electric furnace dust, converter secondary dust, dust sludge, fuming furnace dust collection and rotary kiln bag dust, etc. ; The above-mentioned dust is rich in elements such as zinc, lead, iron, silicon, etc., and has been piled up near iron and steel plants and smelters for a long time without effective treatment. It not only takes up a lot of land, but also under the action of rain, the heavy metal zinc in the dust Lead, etc. will seep into the ground and cause groundwater pollution; in addition, dust stacking causes environmental pollution, but also wastes valuable resources such as zinc, lead, iron, etc.; therefore, wet process is used to treat medium zinc and high zinc dust to recover zinc in dust At the same time, precious metals such as copper, cadmium, cobalt, indium, etc. are enriched, but the leaching rate of zinc, lead, etc. in the wet process is low, and the leaching residue is difficult to use, and the treatment process will introduce sulfur and cause new environmental pollution, etc.; prior art There are also related processes related to zinc-containing dust. For example, 201410176808.5 discloses a smelting method for defluorinating and enriching valuable metals containing fluorine and chlorine suboxide zinc oxide. In a rotary kiln, zinc suboxide is oxidized and roasted at high temperature to remove fluorine. After chlorination, high-purity zinc oxide particles are produced; at the same time, valuable metals are volatilized by high-temperature smoke and flue gas, and after circular spraying and washing, valuable metals enter the spray solution or precipitate to obtain enrichment; further separate the valuable metals in the solution For metals, fluorine- and chlorine-containing sewage is finally treated and discharged up to the standard or reused in the system; although this method recovers a variety of valuable metals in sub-zinc oxide, resulting in high treatment costs, the process is long and the rotary kiln process is used The energy consumption is high, which increases the processing cost; another example is that the application number 201910265052.4 discloses a roasting method of secondary zinc oxide, which includes the following steps: (1) adding water to the secondary zinc oxide powder to wet the mixture, and the moisture is controlled at 8-10 %; (2) Pass the wet secondary zinc oxide powder through a granulation device to make 5-10mm particles; (3) Send the secondary zinc oxide particles into the roasting kiln for 2-3 hours, and control the temperature of the kiln head to 1000-1100 °C , the temperature at the kiln tail is 450-550°C; the pressure at the kiln head is controlled at a negative pressure of 30Pa to 50Pa; the ratio of material volume to kiln volume is 0.3:1-0.6:1; Zinc calcined sand products; although this method can process secondary zinc oxide powder, the energy consumption of the rotary kiln is high, resulting in high processing costs, and the rotary kiln is easy to form rings when processing water-containing materials, which seriously affects normal production

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