No.5 volatilizing kiln is the largest one in Zhuzhou Smelter in China. It is used to treat the slags of zinc service and recover ZnO. The kiln is 58.2 m long and 4.15 m in diameter. After laying 275 mm thick inner lining brick, the net inner diameter is 3.6 M. The kiln is inclined at a certain angle (the kiln head is lower than the kiln tail), about 45% - 50% coke powder and about 509% - 55% zinc leaching residue enter from the kiln tail, and after reaction recovery of ZnO, the remaining residue flows out from the kiln head. The detection temperature of kiln head is about 1250C, and the temperature of reaction zone from 10m of kiln head is estimated to be about 1500C. The temperature of reaction zone is high, coke powder and leached slag undergo violent oxidation-reduction reaction. In order to strengthen the reaction, high-pressure air with air pressure up to 1.8MPa should be blown into the kiln head. The reaction conditions are very bad, and the erosion and wear of refractories are very large.
Our factory is looking for a kind of refractory suitable for the kiln. Many tests have been carried out. Many kinds of refractory bricks of various grades, such as high alumina brick, chrome slag brick, magnesia alumina chrome brick and corundum brick, have been used. On November 26e, 2001, when the lining of kiln 5 was overhauled, we built SA3 "chrome aluminum spinel brick of Jinzhou Great Wall special sand factory at the place 11m ~ 13m away from the worst kiln head condition. On March 11, 2002, the kiln was shut down and operated for 80 days. In the middle, the kiln was shut down for several times due to the failure of mechanical maple. The brick experienced the test of sudden cold and hot. The thickness of this batch of trial bricks is still 120-200 mm when the kiln is put into operation for 80 days. If it is not the other two adjacent bricks, it can no longer be used (other bricks are 50-60mm), this brick can still be used. After that, in order to verify the stability of the quality of the great wall brick, we have carried out many consecutive tests, and the service life is more than 155 days.
Why can great wall chrome alumina spinel brick achieve such a good use effect? After many times of verification, this patented product has the characteristics of large density, low porosity, strong resistance to melt corrosion, good thermal shock stability, and various physical and chemical indexes are obviously superior to other refractory bricks, which is completely suitable for large-scale volatile kilns such as metallurgical kilns with particularly adverse reaction conditions.
After comprehensive comparison with other refractories, this kind of brick has better performance than other bricks, and inspection of the production and development capacity of this factory, we decided to promote the use of this kind of refractory brick in Zhuzhou Smelter. But this brick should adhere to the principle of the best cost performance.
Kiln group of Zhuzhou Metallurgical Machinery Engineering
July 2003