The most important indicators for copper- nickel ore and concentrate electric furnace melting are: furnace productivity, power consumption, nickel content in slag, consumption of auxiliary materials, and furnace utilization factor. Table 1  Electric furnace smelting furnace slag composition (%) example factory Ni Cu Co FeO SiO 2 MgO CaO Ai 2 O 3 North Nickel Corporation 0.07～0.09 0.06～0.09 0.025 24~26 43～45 18~22 2.5 to 4 5~7 Beichenjia Company 0.08~0.11 0.08~0.11 0.03 to 0.04 28~32 41～43 12-15 3 to 5 8~10 Thompson 0.17 0.01 0.06 47~50 35~36 5 4 6 Jinchuan Company 0.08~0.14 0.1 0.06 30 40 16~19 6-8 - Ji Nickel 　 0.042 0.118 Fe36 60 twenty two 5 8 Russenburg 0.1 　 　 20 41 15 15 6 Table 2   Examples of main technical and economic indicators for smelting of copper sulfide concentrate electric furnace project Bechenga the company Norll Sk the company North Nickel Corporation Jinchuan the company Ji Nickel the company Productivity / ( td -1 ) 760 1000 790 450 ~ 550 280 Lt solid charge power consumption / ( kW.h ) 710 ~ 730 600 ~ 625 810 ~ 850 600 ~ 650 740 gold Genus Back Receive rate / % nickel é” in Ni Cu Co 9.62 95.4 79.5 96.4 94.4 78.8 88 to 90 88 to 90  95 94 furnace Slag in Ni Cu Co 2.1 2.9 9.58 2.4 4.3 20.8 smoke dust in Ni Cu Co 0.2 0.2 0.12 0.2 0.3 0.1 Not Recycling loss Ni Cu Co 1 1.5 0.8 1.0 1.0 0.3 Lt solid Furnace aid Material consumption Electrode paste / kg Refractory brick / kg Quenching water /t 3.6 0.65 16 2.4 3 0.79 7 Furnace utilization power /% 92.5 89.5 ~ 89.8 79.2 nickel é” to make this / % Raw material fee Auxiliary material fee Electricity fee Water fee Wages and surcharges Depreciation of major equipment Workshop management 72.85 1.87 13.9 1.1 4.16 0.72 5.4 87.3 0.67 7.88 0.17 0.78 0.68 2.52 79.57 1.94 10.3 2.56 1.04 10.84
Air Covering Double Winder Machine
Applied range:
It is applied to terylene, chemical fiber, high-low stretch yarn and spandex, which can be air covered or doubled.
Features:
1,By air pake function, with synchronous transmission of spandex draft than solution function, to ensure the transmission accuracy;
2, Equipped with feed drive, can accommodate more yarn.
3, Installation bolt automatic stop function and the length count function.
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1) Productivity of electric furnace The production capacity of electric furnace is one of the important indexes in smelting production. It depends on the power and utilization coefficient of electric furnace transformer, physical and chemical properties of materials, electrical system, material quality, feeding method and stability of process technology conditions. , the technical status of the furnace, the working experience of the operators, etc. The formula for calculating the day and night productivity of the electric furnace is as follows:
Circadian B = P.24.cosøK 1 K 2 / A ( t)
In the formula, B day and night - daily treatment charge, t / d;
P—the power of the electric furnace transformer, kVA;
Cosø—power factor (97 to 0.98 at 0 °C);
A—electrical energy consumption, kWh/t;
K 1 — transformer power utilization factor, generally 0.9 to 1.0;
K 2 - time utilization factor, generally 0.92 to 0.95.
2) Single-consumption of electric energy The electric energy consumed by melting 1t of solid material is called electric energy consumption. The method for determining the unit consumption of electric energy is to divide the electric energy (kWh) consumed in the smelting material for a certain period of time by the amount of the material smelted in the time.
There are many factors affecting the power consumption of electric furnaces, mainly the following:
(1) Influence of physical properties of the furnace The experiment proves that the most suitable particle size of the electric furnace smelting material is 30-40 mm, and the material of such granularity is smelted, and the slope of the material is buried deep into the slag layer, thereby preventing the unfavorable overheating of the smelting product. When the electric furnace is added to the powder ore, it can only be operated on a low slope, and the slag layer buried in the material slope is very shallow. Therefore, the slag pool is overheated and the heat it stores cannot be used to completely melt the material. Therefore, smelting powder ore usually consumes more electricity than smelting ore.
(2) Reasonable control of operating conditions When the slag is released, the heat taken away accounts for 30% to 35% of the total heat expenditure. If the lower slag discharge temperature can be controlled, preventing the slag from overheating will increase the heat utilization rate.
1 Select the appropriate secondary voltage. According to the change of production, the working voltage and power should be correctly selected. If the voltage of the advanced section is improperly selected, the active power will be reduced to increase the power consumption. Otherwise, the working voltage will be too low, the electrode will be inserted too deeply, the current will increase, and the line will be lost. Increase. The purpose of adjusting the secondary voltage is to concentrate the heat energy in the slag-electrode contact zone to achieve the purpose of effectively melting the charge.
2 operational impact. The feeding operation is to prevent the surface of the melt from encrusting. When the surface of the melt is severely crusted, the feed is stopped to melt the shell and consume electrical energy. According to the amount of feed, it is reasonable to adjust the power supply, which has a significant effect on reducing power consumption. The power utilization factor is actually increased so that the electrical energy is used as much as possible for the melting of the charge rather than the overheating of the melt.
(3) The higher the operating power of the electric furnace of the electric furnace, the smaller the unit consumption of electric energy. This is because the heat lost during the smelting process by the top of the furnace, the furnace wall and the bottom of the furnace is fixed. As the power increases, the thermal efficiency of the furnace will increase. The improvement in the utilization of heat energy increases the amount of melting of the material, so that the electricity consumption is also reduced.
Chemical composition (4) When the material of a high magnesium oxide content in the slag, power consumption also will increase.
3) an amount of solid slag slag nickel and copper-nickel sulfide ore concentrates Furnace charge of 100% to 120%, a nickel-containing slag directly affect the recovery of metal. Therefore, when the slag rate is constant, it is required that the slag contains nickel as low as possible. The slag composition and main technical and economic indicators of the electric furnace smelting furnace are listed in Tables 1 and 2, respectively.
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[next] In order to reduce the nickel content of the slag, the following measures are often used in production:
(1) Control reasonable slag composition. The silica content in the slag increases and the slag contains nickel. However, the excess silica will increase the melting point of the slag, and the SiO 2 is controlled by 39% to 41% in a factory. Alkylene oxide content of the slag to increase the iron content, nickel slag increased, due to excessive oxidation of ferrous the density of the slag is increased, resulting in good separation of the slag sulfonium. Generally, FeO is controlled at 25% to 31%. Appropriate oxygen-stabilized magnesium and calcium oxide levels in the slag help to reduce the nickel content of the slag.
(2) Adding an appropriate amount of carbonaceous reducing agent to the charge can reduce the valuable metal oxide to metal and enter the low nickel ruthenium. Generally, 2% to 3% of a carbonaceous reducing agent is added to the charge. For example, the single consumption of coke breeze in Jinchuan Company's baking smelting is 15kg, and the single consumption of reducing agent in the smelting of Jijin Company is 5kg.
(3) Appropriate control of low nickel niobium grades, such as Jinchuan low nickel niobium containing (%) Ni 12-15, Cu 6-8, vermiculite low nickel niobium containing (%): Ni 12, Cu 2 .
(4) A reasonable operating system. Lower slag surface and higher kneading surface will increase the nickel content of the slag. The amount of slag returned is large, and the loss of valuable metals in the slag increases. The feeding is not carried out according to the technical requirements, the furnace condition is deteriorated, and the slag contains nickel.