Refractories for smelting furnaces
In recent years, metallurgical workers have developed many new or improved smelting furnaces. Different countries have different emphasis on the development and improvement of smelting furnaces due to different raw material taste and production technology experience.
A Mitsubishi smelting furnace
Japan Mitsubishi method continuous copper smelting is by the smelting melt through the airtight flow trough gravity flow transport, melting furnace, slag dilution furnace and smelting furnace connected into a unified whole, complete from copper concentrate to crude copper smelting process. The wet concentrate is oxidized in the smelting furnace to form high grade (60%~65%) matte. Dilution furnace is a settling electric furnace melting furnace and slag into the furnace and sedimentation separation, slag; The high grade matte is oxidized continuously to coarse copper in the furnace, and the slag is returned to the smelting furnace.
(1) smelting furnace: concentrate is sprayed from the top of the furnace, and a burner is arranged on the side of the top of the furnace to supplement the heat. The resulting matte and slag flow into the dilution furnace through the overflow port and the flow groove. The flow groove is provided with a gas nozzle for heat preservation.
(2) slag dilution furnace: slag and matte are stratified in the electric furnace. The matte flows into the blowing furnace through the flow groove through the siphon mouth, and the upper furnace slag is reduced and diluted under the action of adding coke powder to become discarded slag.
(3) Blowing furnace: the top of the furnace is equipped with a spray gun, which is composed of sandwich steel pipe. The inner layer is fed with limestone flux, and the oxygen-rich air of 26%~35%O2 is sprayed into the middle of the sandwich to blow the continuous inflow of high-grade molten copper and sulfur into coarse copper. Naoshima Smelter in Japan adopts Mitsubishi furnace blowing, furnace shell inner diameter of? 9250mm, furnace lining material for magnesia-chrome brick. Due to the continuous production of the furnace, there is no structural spalling problem, so the lining life of the furnace is longer.
B Flash furnace
The flash furnace is a similar flash furnace to the flash furnace developed by Kennecott (USA) and Otokumpu (Finland). The matte can be ground into fine particles and sprayed into a furnace for oxidation. The treatment of cold copper can come from a variety of melting furnaces, unlike Mitsubishi method, the melting furnace (or furnace) flow of the flow of copper continuous stability, unlike P-S converter requirements melting furnace has a large storage capacity of copper. Flash converting process solved the leakage problem of sulfur from the technology, its characteristic is: melting furnace output high grade (68% ~ 70% Cu) copper sulfide, granulating by high pressure water quenching, copper sulphate particles after dehydration, dry fine grinding in flash smelting furnace with oxygen enriched air (70% O2) converting into thick copper, flux by CaO, the concentration of SO2 in flue gas can reach 43.6%, copper slag containing high about 16%, need to return to smelting system. Due to the small and stable amount of gas produced and the high concentration of SO2, the scale of supporting flue gas cooling, purification and acid production system is much smaller, so the infrastructure investment of flash blowing process can be reduced by 35% compared with converter process. This process is continuous operation, easy to control of the production process, production cost is low (10% ~ 20% lower than the converter), tons of copper is only 25% of the converter process energy consumption, water consumption reduced the 3/4, sulfur recovery rate reached 99%, concentration of SO2 in tail gas is 100 * 10 ˉ 6, only is far lower than the standards stipulated by the new pollution 600 * 10 ˉ 6.
C Noranda stove
The Noranda converter, developed by the Noranda Research Centre in Canada, is essentially an improved version of the traditional P-S converter, which allows the operation in a close or continuous manner. Its production is characterized by the coexistence of three phases in the furnace, that is, in the whole operation period in the furnace are retained slag, white copper sulfur and sulfur content of high crude copper (referred to as semi-crude copper). During operation, high grade liquid sulfur (the iron content is less than 4%), return material, solid sulfur, flux from the furnace, slag from the slag mouth, half coarse copper from the copper mouth, so in addition to the furnace to skimmer, the eye is always continuous blast. As a result, the Noranda converter has a much higher blast rate than a single P-S converter. So its lining life is much higher than P-S converter.
D Aos furnace (Essa furnace)
Austin furnace is a kind of cylindrical container lined with high quality magnesite chrome brick, water quenching of copper sulfur when working from loading port to join, immersion spray gun from the top center of stainless steel spray gun is inserted molten pool, the blowing air oxygen content 40% ~ 50%, injection of oxygen-enriched air makes the melt strongly agitation, chemical reaction going very quickly, so small specifications of the furnace can obtain high production capacity, concentration of SO2 in a flue gas can be as high as 10%.
E cardo converter
The Kaldo converter uses a non - immersion spray gun, whose furnace body can rotate up and down, or around the central axis. During operation, dry concentrate is supplied by the inner tube of the spray gun, and oxygen-rich air is supplied by the outer tube of the spray gun. The self-heating reaction is maintained by adjusting the ratio of oxygen to material.