Regarding the new technology of modern copper smelting, it involves flash smelting, Isa copper smelting method, Baiyin copper smelting method, Ausmet copper smelting method, and Shuikoushan copper smelting method.
Abstract: Since the advent of Outokumpu in Finland in 1949, flash smelting has gradually replaced the reverberatory furnace and blast furnace through continuous improvement and improvement. It has also become the most competitive smelting technology used in copper metallurgy today and is considered the most standard clean copper smelting process. Flash smelting has very strict requirements on charge preparation. Rotary kiln drying and air flow drying are generally used for drying concentrates in production. Features of flash smelting:
1. Flash smelting
Since the advent of Outokumpu in Finland in 1949, flash smelting has gradually replaced the reverberatory furnace and blast furnace through continuous improvement and improvement. It has also become the most competitive smelting technology used in copper metallurgy today and is considered the most standard clean copper smelting process. Flash smelting has very strict requirements on charge preparation. Rotary kiln drying and air flow drying are generally used for drying concentrates in production. Features of flash smelting:
(1) Flash smelting is a kind of suspension smelting. The three-phase gas-liquid-solid phase completes a series of reaction processes in the reaction tower in 1 to 2 seconds. The application of oxygen enrichment accelerates the reaction speed, so the production capacity is large;
(2) Flash smelting is a continuous and stable process with high SO2 concentration and stable flue gas composition, which is beneficial to acid production and S recovery;
(3) The biggest advantage of flash smelting is to make full use of the huge surface energy of the copper concentrate, that is, to maximize the use of the concentrate's own reaction heat. Autothermal smelting can not only reduce energy consumption and improve production capacity, but also reduce the amount of flue gas;
(4) High degree of automation, stable production and long furnace life;
2. Isa copper smelting method
The ISA smelting process was jointly developed by Mount Isa Mining Limited (MIM) and Australia's Commonwealth Scientific and Industrial Research Agency (CSIRO) in the 1980s. Isaac smelting method, copper flash smelting method, Noranda method, etc., the process can be controlled by computer. The ISA smelting method has a short process flow and simple equipment, so the control system is relatively simple. The ISA copper smelting process processes a wide range of raw materials, including MIM's own chalcopyrite concentrate, converter slag concentrate and other purchased copper concentrates. During the smelting process of the ISA smelting method, as long as the amount of flux and slag is controlled well, and the produced copper matte and slag mixture has enough time to clarify in the holding furnace, the copper content of the slag will be less than 0.6%.
3. Silver and copper smelting method
The silver copper smelting method is a new copper smelting method that smelts copper concentrate to obtain matte. Research and experiments on the silver and copper smelting method began in 1972. Design for industrial production scale began in early 1975, and a device capable of processing 300t of charge per day was first designed. The device was completed in 1976 and produced continuously for 122 days. In 1980, Baiyin Nonferrous Metals Company replaced the traditional reverberatory furnace smelting method with the silver copper smelting method. Based on the original reverberatory furnace, a silver copper smelting furnace with a daily capacity of 800 tons of charge was built, which is now used for production. One of the characteristics of the silver and copper smelting method is that the fuel requirements are not strict. In the past, heavy oil was used as fuel, and there was a burner in the middle of the stove head and the top of the stove. The advantages of the silver and copper smelting method are:
(1) The utilization rate of sulfur in raw materials can reach more than 70%, and the sulfur dioxide concentration of the flue gas produced is relatively high. The sulfur dioxide concentration of the flue gas produced by the furnace can reach 8%~9%, and it can still be used at the outlet of the exhaust machine. Reaching 5% to 7%, it can meet the requirements for acid production and at the same time reduce environmental pollution;
(2) The heat utilization rate is good and the fuel consumption is low. The added heat is only 50% of that during reverberatory furnace melting. The law does not have strict fuel requirements and is in line with China's energy policy;
(3) The requirements for the moisture content of raw materials are not strict, the raw materials do not need to be fully dried, the raw material preparation and transportation processes are relatively simple, and the smoke and dust rate is low;
(4) The silver-copper smelting method has few auxiliary equipment, so there is little infrastructure investment. The silver-copper smelting furnace is a fixed furnace with a simple structure;
(5) The silver copper smelting method not only produces slag with relatively low copper content and does not require depletion treatment, but also can deplete converter slag, which is also an outstanding advantage compared with other enhanced smelting methods;
4. Ausmet copper smelting method
Today's copper-sulfur blowing mainly uses the PS converter process. This process requires a metallurgical package to transport the melt, and the furnace mouth has poor airtightness, causing serious low-altitude SO2 flue gas pollution and safety issues. Ausmet blowing technology is a new technology after the Mitsubishi method and flash blowing technology. It uses a fixed metallurgical furnace instead of a converter. The melt is transferred by a chute. There is a closed fume hood on the chute. The furnace mouth has good airtightness and is easy to operate. There is less unorganized smoke emitted during the process, and it can be recycled centrally. Environmental protection issues are effectively solved, and the level of automation control is high. Its characteristics are as follows:
(1) The continuous blowing mode can produce qualified blister copper. This operation mode has a simple process, the process control furnace temperature and flue gas SO2 concentration are relatively stable, and the environmental protection effect is good;
(2) Since there is no liquid copper matte phase, the burning loss of the spray gun is reduced;
(3) Continuous blowing increases the blowing rate of the blowing furnace and creates conditions for increasing production capacity;
(4) Current technology still has problems such as high copper content in slag and low direct recovery rate;
5. Shuikou Mountain copper smelting method
In the early 1970s, Shuikou Mountain Mining Bureau designed and built a small-scale copper smelting plant with an annual output of 5,000 tons in order to solve the smelting problem of its own uranium-containing copper concentrate. At that time, there was no new equipment suitable for small-scale copper smelting. The copper smelting process adopts the closed blast furnace process commonly used in China. After more than two years of theoretical analysis, small-scale experiments, equipment research, etc., we conducted conditional experiments in a device that processed 50 tons of charge per day. From 1991 to 1992, we conducted longer-term semi-industrial experiments and achieved very satisfactory technical and economic results. index. Obtained Chinese patent rights in 1994 and was awarded the China Patent Excellence Award by the China Patent Office in 1997.
The Shuikou Mountain copper smelting method belongs to the molten pool smelting copper smelting method. The smelting furnace is a horizontal cylindrical furnace. The steel plate shell is lined with chrome magnesia bricks. The furnace body has a transmission device and can rotate 90°. The feeding port and smoke exhaust port , slag discharge port, sulfur discharge port, and an oxygen lance is installed at the bottom. The oxygen lance and brick set are replaceable. The oil burner on the end wall is used for starting the furnace and maintaining heat. The materials complete heating, melting, oxidation, slag making, matting and other processes simultaneously in the furnace, with high mass transfer and heat transfer efficiency. The Shuikou copper smelting method uses bottom blowing matte and jet oxygen lance technology, which can recover arsenic at high speed.
