Bottom-blown smelting—several issues in blast furnace lead smelting
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Our factory uses a bottom-blown furnace process for lead smelting. During this process, there are several issues; we would appreciate guidance from experts: 1. The rate of lead precipitation in the bottom-blown furnace is not high enough, failing to meet the designed level of 38%. The lead content in the granules is ≥53%, sulfur content ranges from 14 to 18%, the oxygen-to-material ratio is 100–120 m3/t, and the slag temperature is 1100°C. 2. The furnace develops slag buildup on average 4 times per month, resulting in a large amount of broken debris; how can we reduce the frequency of such buildup? 3. The high-lead slag stored is prone to breaking. 4. Fluorocarbon materials are used for dust removal with bag filters, but they tend to get damaged, likely due to corrosion by soot. 5. The large lead pots used in electrolysis are heated using gas, and it is difficult to cool them down and remove copper from them without using water
Answer to the fifth question: Do not fill the pot too full when filling it for the first time. Once the lead inside the pot melts, remove the slag and then add the remaining material; this will lower the temperature. However, to remove copper by leaching, water must be added, and then the thin slag is removed. By the way: Is the original poster from Jin Gui Yin Ye?
The procedure is the same: for slag with a high lead content (41% lead), the cooling process is identical; it’s not safe to sprinkle water. Our company was designed by ENFI, and fluorocarbon membranes are used for dust removal in the blast furnaces, but these membranes are prone to degradation and damage. It’s not clear what the corrosive agents are. What’s your situation? Is it possible that the dust concentration removed by the membranes is too high, or that the amount of flue gas that can be processed is insufficient? Also, no funds are provided, so they run out quickly
Please talk about the bottom-blown furnace designed by Shuikoushan Company. What are the rated current and voltage of the electrolytic silicon rectifier? 1. What is the flue gas treatment capacity of the blast furnace’s bag filters? 2. What is the diameter of the U-tubes in the blast furnace’s surface coolers, and what is the cooling area? 3. How long is the time required for slag removal? 4. How thick is the coke layer in the tuyere area? 5. What is the spacing between oxygen lances? 6. What is the height difference between the slag dam and the lead dam in the bottom-blown furnace? 7
The questions you ask are all so insightful, haha. It seems like you have quite a few questions – keep up the good work!
Our bottom-blown furnace is about to go into operation! However, we use hot slag reduction; the reduction furnace is a converter, and coal powder is used for reduction. I’ll have to turn to all of you experts if I have any more questions in the future!
The calcium content in the slag should be higher than 17%; otherwise, the filter bags tend to deteriorate. Should considerations be given to design and daily operation management?
Reply to 8# gzsabc: It’s the same as what we have here; we have been in industrial production for several years already, hehe
The lead sinking rate is highly dependent on the raw materials used; in our factory, this rate can be as low as 23% and as high as 43%. The proportion of flue ash added should not be too large.