Research And Design On Treatment Of Melted Lead Dust From Lead Anode Pot By Multistages Spray Method

Exhaust gas which generated in the producing of lead smelting contains larges of lead particles, usually spreads in the form of lead dust in the air, causing environmental pollution and great harm to human body. The production of lead anode plate electrolytic refining gives rise to very serious dust pollution. The lead smelting enterprises have already adopted the draft straight row, bag type dust and acid, alkali absorption liquid with wet dedusting tower of dust removal equipment effectively improve the working environment and reduce the environment pollution, although still very difficult to reach the discharge standard. With the improvement of environmental protection policy and the increasing national awareness to environmental protection, the enterprises also need pay more and more attention to environment when obtaining economic benefits. Hunan Shuikoushan Nonferrous Metals Co., Ltd plans to adopt efficient absorption liquid with wet dedusting multilevel spray tower to deal with the low-altitude pollution exhaust in the production of lead anode plate electrolytic refining among the three plants. This paper specifically summarizes the design and research in this aspect.The test firstly verifying the main process parameters in this thesis, found out that the multilevel spray dust removing device with different absorbers can achieve high absorption efficiency. There is no big difference in using fluosilicic acid, acetic acid or oxalic acid absorption. The fluosilicic acid carried in the flue gas can make pH value of the absorption liquid stabilize around4and the removal rate reach to98%after passing the level-4spray dust in this condition. The particle removal rate and lead removal rate increases with the growth of liquid-gas ratio but the growing rate gradually slowed down. When the liquid-gas ratio reaches8～16L/mj, the removal rate of particle and lead removal rate rise slowly. The dust removal rate for each level of absorption tower can reach60%-70%, and the dedusting efficiency increases with the improvement of grades. As the gas velocity increases, the dust removal rate of particle and lead removal rate decreases; when the flow rate is4-5m/s, both the rates have a steep drop-trend.Secondly, with the study results, the relevant process parameters are being calculated and designed accurately. The enterprise completed the design and installation of absorption tower, chimney and some other non-standard equipment by using these valued experimented parameters. By means of simulation and fluent software, the enterprise designs the blow-sucking dust shield, including the suitable mask size, rational volume、 air-input angle and size. Besides, it also completes the selection and installation of equipment, estimates the main pollution during the operation and takes relevant measures to deal with.Finally, through the debugging and acceptance to the project, it shows that output particles concentration is less than80mg/m3, lead concentration is less than8mg/m3under low load conditions. The transfinite multiple for the lead dust TWA and STEL around the melting pot and casting-board operation section in workshop meets the requirements of 《Workplace Occupational Exposure Limits for Chemicals Harmful Factors》(GBZ2-2007), so the testing results are qualified.