| The oxygen rich bottom blowing smelting technology is applied to the smelting of arsenic-containing complex concentrates.During the smelting process,arsenic mostly volatilizes into the gas phase in the form of oxidation.Arsenic-containing flue gas produces about 15%arsenic-containing fume from the electrostatic precipitator after cooling and dust removal.Most of the remaining arsenic enters the sulfuric acid purification section along with the flue gas,and the arsenic is brought into the polluted acid by power wave washing.The contaminated acid is finally sent to the sewage treatment station for vulcanization or lime neutralization to produce a large amount of arsenic sulfide slag or calcium arsenate slag.These methods belong to end-treatment technology.The arsenic of smelting white soot produced by oxygen-rich bottom blowing mostly forms complex salts in the oxidation state with iron,lead and zinc,which is difficult to recover and belongs to the refractory intermediate material containing arsenic.Compared with the traditional gold industry,the SO3 content and the flue gas dew point temperature in the bottom blowing smelting flue gas is higher than that in the traditional two-stage roasting flue gas,so it is difficult to adopt the dry quenching to recover arsenic.In view of the above problems,this paper analyzes the principle of arsenic removal by bottom-blown smelting and the behavioral characteristics and distribution trend of arsenic.It is proposed that all arsenic should be opened in the form of arsenic trioxide from smelting white fume and flue gas as raw materials for producing arsenic metal,and the bottleneck problem of arsenic concentrate treatment can be solved from the source.In the research process of recovering arsenic trioxide from smelting electric dust,a process route of sulfuric acid leaching white fume dust-electrowinning copper to separate copper and arsenic-SO2 reduction recovery arsenic-reduction solution return to leaching white fume dust was proposed.The leaching process of sulfuric acid was as follows:the ratio of liquid to solid was 4:1,the initial acid concentration was 15%,the leaching temperature was 80? and the reaction time was 3 h.Under this condition,the leaching rates of arsenic and copper were 76.40%and 96.00%respectively,and the leaching solution contained 24.40 g/L and 29.60 g/L of arsenic and copper,respectively.The reduction process of SO2 was as follows:reduction reaction temperature was 60 C,initial acid concentration was 18%,reaction time was 3 h,flux of SO2 was 20 L/h.Under this condition,the purity of As2O3 was 99.63%,the direct yield of As2O3 was 88.05%,and the utilization rate of SO2 in reduction reaction was 35.85%.The content of As2O3 was 99.63%,Cu 0.001%and Fe 0.002%.The content of other impurity elements such as Pb,Bi and Zn was less than 0.001%,which met the requirements of As2O3-1 quality standard of GB26721-2011.In the research process of arsenic collection from arsenic-containing flue gas,the method of removing SO3 by dry sudden cooling arsenic collection process was first studied.By comparing the effects of two alkaline agents NaOH and Ca(OH)2 in engineering tests,It was concluded that Ca(OH)2 has greater cost and environmental advantages than NaOH.The cost of Ca(OH)2 is 10,800 yuan/d,and the cost of 32%liquid alkali is 99,400 yuan/d.Compared with NaOH,Ca(OH)2 saves 88,600 yuan per day,and there was no irritating gas generated during the experiment,and the working environment was better.The study of influencing factors of arsenic recovery by dry sudden cooling arsenic collection showed that under the conditions of 90 t/h raw material,2.32%arsenic content in furnace charge,150 oxygen to material ratio and 75%oxygen enrichment,the optimum control conditions were as follows:the injection concentration of Ca(OH)2 in quench tower was 11%,and the outlet flue gas temperature of quench tower was 170?.Under these conditions,the purity of As2O3 collected b y bag filter was 70.07%,and the output of As2O3 in 8 hours was 28.5t. |
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