Home > Technology > Manufacturing Tech > Smelting > LS-Nikko Copper Copper smelting using the flash smelting process started in 1949 by Outokumpu Oy's Harjavalta smelter in Finland. It has now become the major copper smelting process. This flash smelting process used preheated air in the early period of development, but in the late 1960's when the technology became stabilized, oxygenated air became the most common. As a result, production costs were saved and environmental problems were solved. On the other hand, as  the technology operating with high-grade matte. became widely used, it became possible to save energy costs by maximizing heat reaction insmelting process and minimizing the  blowing  time in the converter. Such technological developments promoted changes in the production capability of copper smelters. Many smelters became able to treat more concentrates without increasing the amount of gas due to increased oxygen enrichment and Matte grade. The flash smelting process' reaction starts when air, oxygen, dried concentrate, and silica flux are injected into the furnace temperature that is at 1250¡É. Once the materials are put into the furnace at a high temperature, sulfide minerals react rapidly with the oxygen. This reaction melts solids because of the oxidation adjustment of Fe and S and generates a large amount of heat. The goal of flash smelting is summarized below. a. Produce Matte appropriate for converter operation b. Produce slag that contains a low amount of Cu c. Produce gas with an appropriate concentration of SO2 for producing sulfuric acid d. Perform a and b in the shortest time possible by using energy efficiently The major elements of the Outokumpu Flash Smelting Furnace are the concentrate burner, reaction shaft, settler, tap-holes, and uptake. If the fine concentrate injected within the furnace contains moisture, steam membranes surround the surface of the concentrate to momentarily obstruct the oxidation reaction. Therefore, the fine concentrate should be dried sufficiently. The concentrate burner's role is to distribute dried solid feed, air, and oxygen to the reaction shaft to achieve the maximum oxidation rate in the reaction furnace. Following are the functions of the concentrate burner: a. To mix evenly solid feed and process gas: uniform reaction b. Low dust generation: Stable operation of boiler c. High oxygen efficiency : Smelting capacity of concentrate Within the reaction shaft, most of the reactions between the oxygen and Cu-Fe-S feed particles occur. Oxidation of sulfur in its volatile solid form takes place. Molten matte generation drops as well as Fe's oxidation takes place. Molten matte and Slag drop are combined and separated. Matte and slag that have been separated in the settler are tapped through the water-cooled copper block tap-holes. The exhaust from the furnace is a hot gas that includes a volume between 10% to 40% of SO2. a. Dryer and Delivery system b. Oxygen Plant c. Blowers and Blast Pre-heaters (Optional) d. Waste Heat Boiler e. Dust recovery and recycle system f. Off-gas extraction fans (ID fans) g. Acid Plant h. Slag treatment system There have been many studies on the direct production of blister copper from copper ore using a single furnace. Other than exceptional ores, there have not been any successful cases. The Mitsubishi Continuous Process is the most precise form in use. The unique feature of the process is that the furnace is connected by a launder, where the melt continuously flows to each furnace and goes through a series of oxidation reactions according to the oxygen potential. Ultimately it becomes blistered. In the mid 1970's the process completed its pilot stage and the continuous furnaces, which produce 48,000 tons/yr, were installed at the Naoshima refinery. In 1991, the existing reaction furnaces and continuous furnaces were shutdown and continuous furnaces with an annual production capacity of 200,000 tons per year were installed and began operation, finally getting the worlds attention. Australia's Port Kembla Copper Company is replacing the P-S converter that is a major polluter with the C-furnaces using the Mitsubishi Continuous Process. Also, many refineries are considering replacing reaction furnaces with S-furnaces. The Mitsubishi Process is composed of the smelting furnace, electric slag cleaning furnace and the converting furnace. Within the smelting furnace, concentrates, flux, and oxygen-enriched air are injected into the melt through the lance to create 68% matte and slag. The generated matte and slag flow to the electric slag-cleaning furnace through the launder. The Electric Slag Cleaning Furnace is the part of the continuous process where matte and slag are separated. The separated matte flows to the C-Furnace through the launder and slag is granulated by water after flowing through the slag outlet hole. In the converting furnace, oxygen enriched air and lime flux are injected into the matte by the vertical lance to produce molten blister and C-Slag. Molten blister copper is sent continuously to the Anode furnace, and the C-Slag is recycled to the S-Furnace or used as the coolant for the C-Furnace.