Method of recovering valuable metals from zinc bearing materials and blast furnace relevant thereto
AssigneeMitsui Mining & Smelting Co., Ltd.
InventorsHiroshi Tokunaga, Yoshikazu Tatehana, Akira Umekawa
Life of this patent
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Abstract
The blast furnace in the present invention comprises a V-shaped or an inclined hearth, tuyeres disposed along said hearth, a tap hole for discharging matte and/or slag, said tap hole being disposed at the lowest part of the hearth, and dampers having V-shaped or inclined fore end, each of said dampers being disposed to agree with said tuyeres. The present blast furnace, when employed for smelting by feeding briquetted Zn bearing materials as the material thereto and blowing preheated air therein through the tuyeres disposed along the hearth, displays an improved smelting efficiency in separating and recovering volatile valuable metals and non-volatile valuable metals.
Claims10
A method for separating and recovering volatile valuable metals including zinc and non-volatile valuable metals from zinc-bearing materials, utilizing a blast furnace comprising a horizontally elongated hearth whose upper surface is inclined downwardly relative to the horizontal in the lengthwise direction of said hearth toward tap hole means and an array of tuyeres disposed in horizontally spaced-apart relation along the lengthwise extent of said hearth and disposed closely above said upper surface of said hearth, said array of tuyeres being inclined relative to the horizontal at substantially the same angle as said upper surface of said hearth, which comprises the steps of:
- feeding briquettes of said zinc-bearing material containing carbonaceous material admixed therewith through a coking zone which communicates with said blast furnace and in said coking zone heating the briquettes by contact with hot waste gas flowing upwardly from said blast furnace;
- then flowing a thin layer of the coked briquettes downwardly from the coking zone into the blast furnace toward the hearth to form a bed of said briquettes in a reaction zone above said hearth, said layer being of substantially uniform thickness along the lengthwise extent of said hearth, and simultaneously blowing preheated air through said tuyeres into said blast furnace in a lateral direction above the upper surface of said hearth so that the zinc in said zinc-bearing material is reduced to zinc metal and is evaporated and non-volatile materials present in said zinc-bearing material become molten and collect on said hearth and flow toward said tap hole means and simultaneously are contacted by the preheated air supplied through said tuyeres to form an agitated melt from which volatile metals are evaporated;
- flowing the vaporized volatile metals upwardly through said blast furnace and recovering said metals outside said furnace.
A method for separating and recovering volatile valuable metals including zinc and non-volatile valuable metals from zinc-bearing materials, utilizing a blast furnace comprising a horizontally elongated hearth whose upper surface is inclined downwardly relative to the horizontal in the lengthwise direction of said hearth toward tap hole means and an array of tuyeres disposed in horizontally spaced-apart relation along the lengthwise extent of said hearth and disposed closely above said upper surface of said hearth, said array of tuyeres being inclined relative to the horizontal at substantially the same angle as said upper surface of said hearth, which comprises the steps of:
- screening residue from the pyrometallurgical smelting of zinc ore to obtain an undersize fraction having a particle size of less than 20 mm and an oversize fraction having a larger particle size;
- admixing ligno-sulfite liquor with the undersize fraction and then drying that mixture in a first rotary drier to a water content of from 18 to 22%, the total amount of said ligno-sulfite liquor being from 7 to 22%, based on the amount of said undersize fraction, with from 80 to 100% of the total ligno-sulfite liquor being admixed with said undersize fraction and the balance of the ligno-sulfite liquor being added in said first rotary drier;
- placing into a second rotary drier the mixture of undersize fraction and ligno-sulfite liquor obtained in said first rotary drier, together with hydrometallurgical zinc leaching residue and pulverized coal to form a second mixture having a carbon content of 18 to 22% and a zinc content of more than 10% and drying said second mixture to a water content of from 15 to 20%;
- pulverizing the second mixture obtained in the second rotary drier with a rod mill, kneading the thus-pulverized second mixture with a kneader and briquetting the kneaded mixture to obtain briquettes;
- feeding said briquettes and said oversize fraction through a coking zone which communicates with said blast furnace and in said coking zone heating the briquettes and said oversize fraction by contact with hot waste gas flowing upwardly from said blast furnace;
- then flowing a thin layer of the coked briquettes and said oversize fraction downwardly from the coking zone into the blast furnace toward the hearth to form a bed of said briquettes and said oversize fraction in a reaction zone above said hearth, said layer being of substantially uniform thickness along the lengthwise extent of said hearth, and simultaneously blowing preheated air through said tuyeres into said blast furnace in a lateral direction above the upper surface of said hearth so that the zinc in said briquettes and oversize fraction is reduced to zinc metal and is evaporated and non-volatile materials present in said briquettes and oversize fraction become molten and collect on said hearth and flow toward said tap hole means and simultaneously are contacted by the preheated air supplied through said tuyeres to form an agitated melt from which volatile metals are evaporated;
- flowing the vaporized volatile metals upwardly through said blast furnace and recovering said metals outside said furnace.
Dependencies are inferred from the claim text.