ROTARY KILN WITH COMBUSTION CHAMBER FOR SEMI-FUSED REDUCTION SMELTING

摘要

PURPOSE:To increase the yield of valuable metals by a structure wherein the distance between the tip of a burner and the discharge end of the kiln and the length of the combustion chamber in the same direction as the axis line direction of the kiln are made at the ratio of specified percentages of the inner diameter of a shell. CONSTITUTION:When the burner is at the position indicated by the burner 5a, a slag ring first appears at the position abut 15 meters inside the kiln from the discharge end thereof, while, when the burner is at the position indicated by the burner 5b, the slag ring appears in the first place at the position about 18.5 meters inside the kiln from the discharge end thereof. As a result, the effect of suppression of charging amount of raw material to be charged due to slag ring is remarkably influenced by the position in which the slag ring appears in the first place or the deeper the dam ring is formed within the kiln the lower the production efficiency becomes. Furthermore, when the relative position of the tip of the burner to the discharge end of the kiln is smaller than 70% of said inner diameter, the temperature of the product stopped by the dam ring can not be maintained within its suitable temperature range. On the other hand, when siad relative position is larger than 90%, not only the stagnation of the flow of charging raw material and consequently lowering of the productivity are resulted, but also the service life of the kiln is shortened. Consequently, said relative position must be kept in the range of 70-90% of the inner diameter of the shell.