PURPOSE: To recover useful metals in high efficiency without wasting a reducing agent by providing the inner wall of a rotary kiln in the direction of length with plural annular dams so as to divide the kiln into two or more reducing atmosphere zones and one oxidizing atmosphere zone.
CONSTITUTION: The rotary kiln 1 is provided, on the inner wall thereof, with the primary and the secondary intermediate dams 6, 7 to divide the inside of the kiln 1 into the primary and the secondary reducing atmosphere zones A, B and the oxidizing atmosphere zone C. A mixture of dust and solid carbonaceous reducing material is charged from an inlet 1a, which is passed through the primary reducing atmosphere zone A, stopped by the primary intermediate dam 6, and deposited. Subsequently, the above mixture overflows the primary intermediate dam 6, which is passed through the secondary reducing atmosphere zone B and then stopped by the secondary intermediate dam 7. As the result of the increase in the length of time required for the above movement, above-mentioned mixture is thoroughly dried and heated, so that zinc oxide, lead oxide, etc., are actively reduced and vaporized, and separated from the dust, which is fed into the oxidizing atmosphere zone C so as to reoxidize the reduced metals and to discharge them from an outlet 1b.
TOSHIN STEEL CO
HIMEJI TEKKO RIFUAIN KK
| JPS6053090A | 1985-03-26 | |||
| JPS58141345A | 1983-08-22 | |||
| JPS58136731A | 1983-08-13 |