A kind of direct-reduced iron production intermediate frequency furnace
Technical field
The utility model relates to a kind of direct-reduced iron production intermediate frequency furnace, belongs to the direct-reduced iron processing technique field.
Background technology
China's Iron And Steel Industry develops rapidly, has become in the world first to produce steel big country and consumption steel big country.Output of steel was broken through 700,000,000 tons in 2011, year needs more than 9,000 ten thousand tons of steel scraps, the reduced iron demand is 5,000,000 tons (wherein the import reduced iron is more than 400 ten thousand tons), but the output of China's direct-reduced iron is not as good as the output of India's two weeks, cause the direct-reduced iron of Iron And Steel Company that a large amount of breach is arranged, a large amount of external direct-reduced irons of import of the flower high price of having to.Therefore, China is not iron and steel power, and steel products do not have competitive power in the international market, aspect rolling shapes and quality, also are not suitable with the requirement of the national economic development.China also will reach more than 4,000 ten thousand tons of imported steels (mainly being high-quality steel and special steel) from external every year, and sponge iron solves the unique indispensable starting material of high-quality steel and special steel just.And the direct-reduced iron of China (sponge iron) annual production only is 600,000 tons, and world's metallurgy industry is decided to be zero to the sponge iron output of China.China is again the abundant country of a Sweet natural gas and coking coal reserves, in addition poor, thin, the assorted iron ore deposit of China, and direct-reduced iron can not form mass-producing always.Therefore, country puts into effect relevant policies, encourage growth direct-reduced iron and the technological development of Fei Jiao iron-smelting process and application.Improve a large amount of poor, thin, assorted iron ore deposit and iron-containing waste and the abundant coal resources of quantity and quality and exploitation China of reduced iron, making its resource utilization is an extremely urgent cause.
Direct-reduction technique difference according to the use reductive agent in the world's can be divided into two large classes: use the gas base directly reducing method of gaseous reducing agent and the coal-based direct reduction method of use solid reductant.In the process of moving towards iron and steel power, the sponge iron industry of national resource feature is based oneself upon in development, be only the only way which must be passed of development iron and steel power, the gas base directly reducing method, mainly be distributed in the abundant area of the natural gas sources such as the Middle East, South America, these areas also obtain fast development take the short flow process of electric furnace as main Iron And Steel Industry.Representing technique is Midrex shaft furnace process, HYL retort process making sponge iron and fluidized bed process.The coal-based direct reduction method mainly is distributed in the ground such as South Africa, India, New Zealand, and natural gas source is limited, but iron ore deposit and the abundant coal resources of high-quality are arranged.Represent technique SL-RN method and Krupp method are arranged.
China is from energy reserve and rationally utilize consideration, can't provide enough Sweet natural gases for metallurgical industry production, even there is gas available, cost is high too, produces one ton of sponge iron, if want 400-500m3 with Sweet natural gas, if use coal gas, 1600m3.Therefore gas base directly reducing can't be considered.Use at home more technique that three kinds of tunnel furnace technique, rotary kiln technology and down-draft kiln techniques are arranged, be the coal base reduction method, the research experiment of some other techniques has also been done by more domestic units, does not all obtain the success that industrialness is produced.Thereby coal-based method production sponge iron technique is the first-selected technique of China.
Down-draft kiln in China's development early, its characteristics have: less investment, upper detective, cost is low, scale is flexible, simple to operate, starting material are required low, but its poor product quality and unstable, production efficiency is low, energy consumption is high, labour intensity is large, operating environment is poor, environmental pollution is serious, equipment is backward, total man worker's operation, machinery-freeization can be sayed, but using because its less investment also has some small business, country does not advocate use.
The rotary kiln technology characteristics: mechanization degree is higher, operating environment, pollute gentlyer, but also exist this that product cost is high, investment is large, be easy to occur the ring formation fault, quality product is lower, stacking factor low (generally 10%-20%), the division in product rate is high.Raw material and reductive agent are required harsh, the shortcoming such as production efficiency is lower, and thermo-efficiency is low has several to use at home, but all not too successful.
Traditional tunnel furnace technique must adopt expensive fire-resistant can, technique is backward, energy consumption is high, and (direct-reduced iron per ton will consume 500-650 ㎏ reduction coal, also to consume 450-550 ㎏ heating coal), the recovery time long (48-76h), the labor force consumes height, unstable product quality, production run cost height, slack market, this technique also exist environmental pollution serious (solid waste such as reduction coal ash, useless reduction tank are many, dust is many), to shortcomings such as ingredient requirements too high (TFe 〉=66%).
Above-mentioned all direct-reduced iron technology both domestic and external all can't utilize low grade ore and iron-containing waste direct-reduction to go out high-grade reduced iron product.
Summary of the invention
The purpose of this utility model is, a kind of direct-reduced iron production intermediate frequency furnace is provided.In China's low-grade iron ore resource and enrich on the basis of coal resources, after the lump ore of any grade and an amount of reductive agent being mixed, become sponge iron through intermediate frequency furnace with direct-reduction.
The technical solution of the utility model.Direct-reduced iron production intermediate frequency furnace, structure comprises body of heater, furnace body outer wall is provided with flame-proof thermal insulation material, in flame-proof thermal insulation material, be provided with coil, in body of heater, be provided with heating liner, the heating liner both sides are for adding thermofin, and the body of heater top is provided with opening for feed and flue, is provided with discharge port in the support of bottom of furnace body.
Above-mentioned direct-reduced iron production intermediate frequency furnace, below opening for feed, being provided with the top in the described body of heater is the fire-resistant minute bed of material of taper.
Above-mentioned direct-reduced iron production intermediate frequency furnace, the described thermofin that adds is divided into preheating section, intensification section and reduction reaction section from top to bottom.
Existing direct-reduced iron working method can be divided into two large classes: use the gas base directly reducing method of gaseous reducing agent and the coal-based direct reduction method of use solid reductant.No matter be which kind of method, the iron ore raw material grade of reducing is all required too high (TFe 〉=66%).The utility model becomes sponge iron through device of the present utility model with solid-state direct-reduction after the lump ore of any grade can being mixed as reductive agent with an amount of charcoal piece, and degree of metalization can reach more than 96%.Needed energy is to be inputted by external electric energy in the production process, in whole technological process, there is not outside air to enter, the gas that carbon is sent in the process of reduced iron only has CO gas, whole flue gas obtains pure CO gas after purifying, can be directly used in generating, for reduction intermediate frequency furnace self.Device of the present utility model has been broken away from the restriction to iron ore grade and colliery quality and kind, reductive agent both can be coking coal, brown coal, it also can be the carbon dust of enrichment in large trade waste degree of depth resource utilization removal process, it is abundant to draw materials, simple in structure, technology is reliable, environmental-protecting performance is good, significantly reduced production cost, particularly improved the added value in the production process, can be very low initial amount, the ultralow grade valuable metal ore deposit that at all can not be referred to as ore deposit enrichment of ore-forming in slag or in the off-gas recovery thing in the production process of direct-reduced iron forms new resource.
Embodiment
Embodiment of the present utility model.Direct-reduced iron production intermediate frequency furnace, structure comprises body of heater, furnace body outer wall arranges flame-proof thermal insulation material 4, at flame-proof thermal insulation material 4 interior installation coils 3, heating liner 6 is installed in body of heater, and heating liner 6 both sides are for adding thermofin 5, and material carries out reduction reaction within adding thermofin 5, the body of heater top arranges opening for feed 7 and flue 8, the support 2 interior installation discharge ports 1 of bottom of furnace body.Convenient for feeding, in body of heater the top being installed is the fire-resistant minute bed of material of taper, and after material can being entered from opening for feed 7, by the conical top sub-material of the fire-resistant minute bed of material 9, evenly landing is to adding thermofin 5.Heating liner 6 adopts silicon carbide or heating graphite courage, also can be the metallic object heating liner.The described thermofin 5 that adds is divided into preheating section, intensification section and reduction reaction section from top to bottom.
Working process is as follows:
A, sweetening agent, dephosphorizing agent, reductive agent mixed after, dry again to material moisture less than 3%, the material after the oven dry is pulverized, the crushing material granularity obtains reducing additive below 1.5mm.
B, iron ore is pulverized post-drying, material moisture is less than 3%;
C, will reduce additive and iron ore powder and send in the body of heater of intermediate frequency furnace from opening for feed 7, material enters and adds in the thermofin 5, by heating liner 6 heating, material is preheated to 300 ℃-500 ℃ at preheating section first, enter the section that heats up and be warming up to 900 ℃-950 ℃, be heated to 950 ℃-1100 ℃ in the reduction reaction section again and carry out reduction reaction, the iron oxide reduction in the ore obtains fe, then fall into the cooling section in the support 2, come out of the stove after waiting the material cooling.
D, the material of coming out of the stove, are selected the iron of reduction by magnetic separation through further carrying out fragmentation after the cooling, by the briquetting press compound stalk forming, obtain direct-reduced iron again.
The above, it only is preferred embodiment of the present utility model, be not that the utility model is done any pro forma restriction, any technical solutions of the utility model content that do not break away from,, all still belong in the scope of technical solutions of the utility model any simple modification, equivalent variations and modification that above embodiment does according to technical spirit of the present utility model.