CN105112663B - A kind of combined producing process of high carbon ferro-chrome and semi-coke - Google Patents
A kind of combined producing process of high carbon ferro-chrome and semi-coke Download PDFInfo
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Abstract
The present invention provides a kind of high carbon ferro-chrome and the combined producing process of semi-coke, including preparation coal and ferrochrome fine ore are used as raw material；Semi-coke is made in lump coal pyrogenation and carbonization；By ferrochrome fine ore and the last mixed grinding of fine coal, semi-coke, green pellets is made in addition binding agent and water；Green pellets is loaded into rotary hearth furnace and carries out high-temperature roasting reduction, reducting pellet is made；Reducting pellet is cooled down, with semi-coke block, flux dispensing, adds and obtained high carbon ferro-chrome product is smelted into closed electric furnace.In the technique, the power consumption of electric furnace smelting is~2400kw ﹒ h/t.
Description
Technical field
The present invention relates to ferroalloy and semi-coke production field, and in particular to the Joint Production work of a kind of high carbon ferro-chrome and semi-coke
Skill.
Background technology
Chromite is the important source material that ferroalloy produces high carbon ferro-chrome, and wherein lump ore accounts for the 20% of total amount, and remaining is powder
Ore deposit.With the consumption of high-quality natural lump ore resource, price more cheap fine ore turns into the primary raw material of ferrochrome smelting instantly.Powder
Ore deposit raw material can't directly enter stove by prior art and smelt completely, electric furnace gas permeability otherwise can be made to be deteriorated, the working of a furnace deteriorates and energy
Consumption increase, so the pretreatment that fine ore has to pass through.The preconditioning technique of current ferrochrome fine ore mainly has sintering, cold-pressing balls, ball
Group's technique.
, substantially will be to after 1400 DEG C because chromite melting temperature in itself is high although sintering process comparative maturity
The liquid phase of generation just can progressively be stablized, so with the shortcomings of the presence of chromite sintering process yields poorly, burnup is higher.
Cold pressing ball has that technique is simple, equipment is few, production cost is low, it is environment-friendly the characteristics of, but cold pressing ball production
Product are raw material, and its high-temperature behavior is far away from sintering process and pelletizing method.
Domestic sintering process and universal very high (the ＞ 3400kwh/ of the follow-up burried arc furnace technique melting electric consumption of cold pressing ball
T), the index request (Cr of GB50632-2010 iron and steel enterprises energy-saving design specification medium high carbon ferrochrome smelting power consumption is not reached far2O3
＞ 40% ,≤2800kwh/t).In addition, sintering process and cold pressing ball can not balance the coal gas of electric furnace recovery.
Pelletizing process mainly includes pre-reduced pellet method and agglomerates of sintered pellets preheating method.
Pre-reduced pellet method is the technology of Japan's exploitation, and its flow is by chromium powder ore and pulverized coal grinding, drying, mixing, again
Plus bentonite and the water pelletizing on disc balling machine, pelletizing is dried in drying grate, then delivers to rotary kiln progress prereduction.It is pre- to go back
Protocorm group and coke, silica and dolomite dispensing, feeding closed electric furnace smelt into ferrochrome.This technique is mainly characterized by electric furnace
Production capacity is improved, power consumption is reduced, save coke.Production practices show：Enter stove in the pelletizing cold charge of degree of metalization~60%
In the case of, electric furnace smelting power consumption~2250kwh/t.
Due to the easy ring formation of rotary kiln high temperature, so pre-reduced pellet method is harsher to chromite and coal dust ingredient requirement,
And time needed for rotary kiln prereduction it is longer (>2h), burnup is also high.
Agglomerates of sintered pellets preheating method is the technique that Finland develops, and its flow is that chromium powder ore is used into wet lapping, by ceramics
Filtering means dehydration is mixed to 10%, then with bentonite in filter, and pelletizing is made of pelletising drum and is calcined, the pelletizing after cooling
Laggard shaft roasting preheating, shaft furnace is connected hot charging pipeline with electric furnace, and acid pellet directly enters electric furnace smelting.Shaft furnace is returned with electric furnace
The coal gas of receipts is fuel.This technique is mainly characterized by that power consumption is low, furnace operation is steady.500 DEG C~750 DEG C of acid pellet
Hot charging enters stove, electric furnace smelting power consumption~2800kwh/t.
But agglomerates of sintered pellets preheating method also can not the coal gas that reclaims of complete equipilibrium electric furnace, extra increase coal gas generating equipment
Cost of investment is higher.
The pyrolysis solid product of coal is coke, according to the difference of pyrolysis temperature, can be divided into high-temperature coke and low-temperature coke.It is high
The pyrolysis temperature of warm destructive distillation is usually 950 DEG C~1100 DEG C, and the pyrolysis temperature of low temperature distillation is usually 500 DEG C~700 DEG C.It is high-strength
The metallurgical coke of degree is that obtained by high-temperature retorting, semi-coke production is then more based on low temperature distillation.Semi-coke ratio resistance is high, reactivity is good,
Ash content is low, is the ideal carbon reducing agent of smelting high carbon ferrochrome.
China's semi-coke industry uses internally heated retort oven.Coal in gas retort by retort section when (pyrolysis temperature is about
700 DEG C), decomposite coal tar oil and gas.Coal tar is raised above with raw coke oven gas, raw coke oven gas and the relatively low coal of temperature from top to bottom
Material carries out heat exchange, and raw gas temperature is gradually reduced, and coal charge temperature gradually rises.Gas retort both sides are provided with combustion chamber, pass through
Raw coke oven gas after reclaiming clean enters combustion chamber with air through burner, and the high-temperature flue gas that burning is produced provides heat for coal carbonization
Amount, and as raw coke oven gas discharges out of the furnace.
The coal gas that internally heated retort oven is produced, due to containing substantial amounts of N2And CO2, calorific value is relatively low, usually 1500~
2000Kcal/m3.Because nitrogen is inert gas, calorific value of gas is not only reduced, and it is further to also increase tail of semi coke
The difficulty of processing synthesis material gas.
Internally heated retort oven requires coal charge in addition to possessing certain calorific intensity, and inside will have enough spaces, in favor of cigarette
Gas heat carrier passes through, therefore the technique is generally limited to the lump coal using granularity in 30mm~80mm.Extensive mechanization fully mechanized mining is very
Difficulty meets requirement of the technique to coal cinder degree, and the lump coal ratio after raw coal screening is not high, and some fine coal rates are more than more than 60%.Cause
This, numerous semi-coke factories are by under a large amount of sieves<30mm little particle or fine coal is sold at a bargain, and this not only has a strong impact on the economy of enterprise
Benefit, and the raw material availability of pyrolysis is greatly reduced, also result in the invalid of the part coal resources and repeat to transport.
In addition, semi-coke industry the problem has：The surplus gas produced in semi-coke production is not used, a lot
Small semi-coke factory is emptying burning, and which results in the significant wastage of the energy；Semi-coke can also produce one in transport and drying process
A little semi-coke ends, semi-coke end, which can not enter electric furnace smelting, causes the waste of semi-coke resource.
The content of the invention
The technical problems to be solved by the invention are to overcome the deficiencies in the prior art there is provided a kind of technically reliable, save and throw
Money, the high carbon ferro-chrome and the combined producing process of semi-coke for improving resource and comprehensive utilization of energy.
In order to solve the above-mentioned technical problem, should the invention provides a kind of high carbon ferro-chrome and the combined producing process of semi-coke
Technique comprises the following steps：
(1) raw material prepares：Prepare coal and ferrochrome fine ore as the granularity of raw material, wherein ferrochrome fine ore<10mm；
(2) preparation of semi-coke
Semi-coke is made for pyrogenation and carbonization in 30~80mm lump coal feeding retort in granularity in coal, wherein, pyrogenation and carbonization
Temperature be 950~1100 DEG C；In gained semi-coke product, granularity is smelted for 10~30mm block for TAP HOLE OF HIGH CARBON FERROCHROMIUM,
Granularity<Green pellets matches somebody with somebody carbon during 3mm semi-coke end is produced for high carbon ferro-chrome；
(3) pressure ball
Ferrochrome fine ore and carbon reducing agent are separately dried the mixed grinding to water content≤4% and water content≤3%, added
Adding additives and water, it is 5~7%, a diameter of 20~40mm green pellets that moisture, which is made, and the percentage is weight percent
Than；
Wherein, the carbon reducing agent is granularity<30mm fine coal and granularity<The mixture at 3mm semi-coke end, semi-coke end
Mass ratio with fine coal is 1:1~40；
(4) reduce
Green pellets made from step (3) is directly loadable into rotary hearth furnace and carries out high-temperature roasting reduction, reducting pellet is made；Its
In, the recovery time is 25~85min, and reduction temperature is 1100~1350 DEG C；
(5) smelt
Reducting pellet made from step (4) is cooled to 50~300 DEG C, with semi-coke block, molten of the granularity for 10~30mm
Agent dispensing, is added into closed electric furnace, carries out smelting obtained high carbon ferro-chrome product at 1650~1700 DEG C.
Foregoing high carbon ferro-chrome and the combined producing process of semi-coke, the technique also utilize step including (6) off-gas recovery：
Coal gas after retort reclaiming clean, voltage stabilizing is delivered to other users；
After the purification of tail gas removing dust, voltage stabilizing obtained by electric furnace smelting, a part delivers to rotary hearth furnace burning, and a part delivers to it
He is user.
Foregoing high carbon ferro-chrome and the combined producing process of semi-coke, coal described in step (1) are lower-grade metamorphic bituminous, such as long flame
Coal, non caking coal and weakly caking coal.
Foregoing high carbon ferro-chrome and the combined producing process of semi-coke, the origin of heat of retort described in step (2) in turn
Bottom stove uses purity>The high-temperature flue gas that the oxygen combustion of 90% (preferably purity is 99%) is produced.
In foregoing high carbon ferro-chrome and the combined producing process of semi-coke, step (3), according to fixed carbon in carbon reducing agent
Amount of allocating is the 8~14% of ferrochrome fine ore quality, and ferrochrome fine ore is mixed with carbon reducing agent, is preferably ground to granularity small
In 0.074mm particle more than 65%.
In foregoing high carbon ferro-chrome and the combined producing process of semi-coke, step (3), the binding agent is selected from bentonite, water
One or more in glass, molasses, spent pulping liquor, the addition of binding agent is the 1~6% of ferrochrome fine ore quality.
In foregoing high carbon ferro-chrome and the combined producing process of semi-coke, step (4), the carbon left for controlling reducting pellet is 2
~5%, the percentage is weight percentage.
In foregoing high carbon ferro-chrome and the combined producing process of semi-coke, step (5), the flux is in silica, lime
It is one or two kinds of.
Foregoing high carbon ferro-chrome and the combined producing process of semi-coke, the granularity of the silica is 10~80mm, wherein granularity<
20mm silica is not more than 5%；By weight percentage, SiO in silica2Content >=97%, Al2O3Content<1%.
Foregoing high carbon ferro-chrome and the combined producing process of semi-coke, the granularity of the lime is 20~80mm；With weight hundred
Divide than counting, CaO content >=85%, P content≤0.02%, SiO in lime2Content≤3%.
Using technical scheme, at least have the advantages that：
(1) utilization of resources of semi-coke is improved, fine coal and semi-coke end has been obtained effective utilization；
(2) energy consumption of semi-coke production is reduced, the quality of semi-coke product is improved, while adding the tail of semi coke of recovery
Amount；
(3) utilization of resources of ferrochrome fine ore is improved；
(4) melting electric consumption of high carbon ferro-chrome is reduced, production capacity is improved, the energy has been saved；
(5) use and the greenhouse gases CO of block Jiao of high carbon ferro-chrome is reduced2Discharge, beneficial to environmental protection；
(6) production technology formation closed circulation industrial chain, comprehensive benefit is good.
Brief description of the drawings
Fig. 1 is the schematic flow sheet of high carbon ferro-chrome of the present invention and semi-coke combined producing process.
Fig. 2 is flue gas flow schematic diagram of the present invention.
Embodiment
To be fully understood by the purpose, feature and effect of the present invention, by following specific embodiments, the present invention is done in detail
Describe in detail bright.
The high carbon ferro-chrome and semi-coke combined producing process of the present invention, in the production process of semi-coke, the temperature of pyrogenation and carbonization
For 950~1100 DEG C, the yield and quality of semi-coke are improved；The Commercial cultivation of the high carbon ferro-chrome small ferrochrome fine ore of granularity, powder
Coal and semi-coke end, improve the utilization of resources.
Specifically, a kind of high carbon ferro-chrome of the invention and the combined producing process of semi-coke, comprise the following steps：
(1) raw material prepares：Prepare coal and ferrochrome fine ore as the granularity of raw material, wherein ferrochrome fine ore<10mm；
The coal is lower-grade metamorphic bituminous, such as jet coal, non caking coal and weakly caking coal；Lower-grade metamorphic bituminous distinguishing feature is ash content
Low, volatile matter content is high, does not glue or weak bonding, suitable for producing semi-coke；Coal is divided into lump coal and granularity that granularity is 30-80mm<
30mm fine coal, lump coal is used for the production of semi-coke, and fine coal is then used for the production of high carbon ferro-chrome, the byproduct semi-coke produced with semi-coke
Carbon reducing agent of the end collectively as rotary hearth furnace reduction；
As shown in table 1, percentage therein is weight percentage the composition of the ferrochrome fine ore.
Table 1
(2) preparation of semi-coke
Semi-coke is made for pyrogenation and carbonization in 30~80mm lump coal feeding retort in granularity, wherein, the temperature of pyrogenation and carbonization
Spend for 950~1100 DEG C.
Retort uses the origin of heat required for internally heated retort oven, retort in the high temperature cigarette of rotary hearth furnace in the present invention
Gas.And the high-temperature flue gas that the origin of heat of conventional internally heated retort oven is produced in the burning of a large amount of firing tunnel in coking furnace.Conventional internal heat type is done
Furnace typically uses air-breathing, N in flue gas after burning2Volume fraction is about 70%, so in the tail of semi coke finally produced
Higher (the N of nitrogen content240%) volume fraction is about.Because nitrogen is inert gas, so tail of semi coke is processed further closing
Effect into material gas is bad.
In the present invention, rotary hearth furnace gaseous fuel is to be used in the totally-enclosed electric furnace coal gas by reclaiming clean, rotary hearth furnace
Pure oxygen burning, oxygen purity is more than 90%, and preferred volume fraction is 99%.CO in the coal gas that general totally-enclosed electric furnace is reclaimed
Volume fraction is more than 70%, N2Volume fraction is less than 10%.(volume fraction is more than the coal gas that totally-enclosed electric furnace is reclaimed with oxygen
90%, preferably 99%) burn completely together, CO in the flue gas of generation2Volume fraction>85%, N2Volume fraction<15%, Er Qiepai
The flue-gas temperature for going out rotary hearth furnace is higher (950~1300 DEG C).
Contain substantial amounts of CO in the flue gas that gas burnup in rotary hearth furnace is produced2.It is in temperature>1000 DEG C of isolating oxygen rings
Under border, CO2It is in an unsure state, if carbon is superfluous in environment, gasification reaction, i.e. CO will occurs rapidly2+ C=2CO.Such as
Contain the green pellets containing water in moisture, such as rotary hearth furnace reduction in fruit environment and be directly entered rotary hearth furnace reduction, rotary hearth furnace flue gas
In also contain certain moisture, will also occur gasification reaction, i.e. H in retort2O+C=CO+H2。
The flue gas of rotary hearth furnace is transported to dry distillation carbonizing furnace, it is anti-carbon gasification will sufficiently to occur rapidly in stove at high temperature
Should, carbonization time shortens, the burnt ability increase of charing production.And because the burning in rotary hearth furnace is pure oxygen burning, the flue gas of generation
Middle nitrogen content is low, so that the tail of semi coke that retort is produced also only contains a small amount of nitrogen (N2Volume fraction<10%), favorably
It is processed further synthesizing material gas in tail of semi coke.
The pyrolytic reaction of coal is the endothermic reaction, and the heat conductivility of coal is poor, therefore is done using 950~1100 DEG C of pyrolysis
Reaction rate can be accelerated by evaporating temperature, increase the yield and intensity of semi-coke.In addition, under high temperature closure anoxia condition, CO2With coal
Occur gasification reaction so as to be converted into CO with the semi-coke of generation, reduce greenhouse gases CO2Discharge so that also make semi-coke have compared with
Big specific surface area and percent opening.Furthermore, energy conservation and consumption reduction effects are notable in semi-coke production.Conventional distillation process needs a large amount of consumption
The semi-coke gas that itself is produced, internally heated retort oven itself destructive distillation heating needs to spend about the 40% of raw coke oven gas total amount.And it is of the invention
Origin of heat needed for the production of semi-coke is outside semi-coke production system (rotary hearth furnace high-temperature flue gas), so semi-coke production need not
Byproduct semi-coke gas is consumed, system aerogenesis quantitative change is big.
In gained semi-coke product, content >=80% of fixed carbon, content≤15% of ash content, described is very weight hundred
Granularity in ratio, semi-coke product is divided to be smelted for 10~30mm block for TAP HOLE OF HIGH CARBON FERROCHROMIUM, granularity<3mm semi-coke end is used for
Green pellets matches somebody with somebody carbon in high carbon ferro-chrome production.
(3) pressure ball
Ferrochrome fine ore and carbon reducing agent are separately dried to water content≤4% and water content≤3%, reduced according to carbon
The amount of allocating of fixed carbon is the 8~14% of ferrochrome fine ore quality to be mixed ferrochrome fine ore with carbon reducing agent in agent, with carbon
Amount is calculated by C/O=0.7~1.2, and mixture is ground into particle of the granularity less than 0.074mm more than 65%, is then bonded
Agent and water, by high-pressure ball press cold moudling, it is 5~7%, a diameter of 20~40mm green pellets, institute that moisture, which is made,
Percentage is stated to be weight percentage；
Wherein, the carbon reducing agent is granularity<30mm fine coal and granularity<The mixture at 3mm semi-coke end, semi-coke end
Mass ratio with fine coal is 1:1~40；The one kind or many of the binding agent in bentonite, waterglass, molasses, spent pulping liquor
Kind, the addition of binding agent is the 1~6% of ferrochrome fine ore quality.
Raw material water content is 8~12% in normal sintering, pelletizing method sintering, and green pellets water in cold compaction ball in the present invention
It is divided into 5~7%.The present invention is using the small cold pressing ball making process of water consumption, so scheme entirety water consumption is minimum, pelletizing is subsequently roasted
The burnup of burning also accordingly reduces.
Grinding that the present invention is used, pressure ball are using the conventional grinding in this area, pressure ball method and apparatus.
(4) reduce
Green pellets made from step (3) is directly loadable into rotary hearth furnace and carries out high-temperature roasting reduction, reducting pellet is made；Its
In, the recovery time is 25~85min, and reduction temperature is 1100~1350 DEG C.
In the step, reduction apparatus can also be using the other conventional equipments in this area, and the present invention is conventional using this area
Commercially available rotary hearth furnace is used as reduction apparatus.In the present invention, rotary furnace bottom is uniformly equipped with green pellets, the thickness of feed layer of green pellets
For 20~40mm.The heat transfer of green pellets and high-temperature flue gas is main based on radiant heat transfer, supplemented by convection heat transfer' heat-transfer by convection in rotary hearth furnace, and 20
~40mm thickness of feed layer is conducive to the quick heating of green pellets and the generation of reduction reaction.
It is many with (Fe, Cr) by the chromium and iron that in the pelletizing of high temperature reduction, are reduced7C3Form is present, when reduction temperature is high
Just there are a small amount of metallic iron, chromium to occur.Reducting pellet has a higher degree of metalization, wherein the degree of metalization of iron up to 40~
85%, the degree of metalization of chromium is up to 15~60%, and total degree of metalization is up to 30~75%.
Oxidizing process can occur for the reducting pellet later stage, for control reducting pellet prereduction degree, reducting pellet match somebody with somebody carbon
Amount is often rich, so final reducting pellet contains certain carbon left.If the carbon left of reducting pellet is too low, it is impossible to protect
Demonstrate,prove the reducing degree of reducting pellet.If the carbon left of reducting pellet is too high, mixed carbon comtent will greatly reduce in electric furnace smelting, can be with
Add and be seldom even not added with block Jiao.
Influence of the carbon left of reducting pellet to Thermal can be understood as in furnace charge containing granularity very tiny Jiao
Charcoal particle.The carbon left of reducting pellet is too high, and its Thermal is more much bigger than the Thermal under general working condition,
Required smelting voltage is caused to substantially exceed rated voltage.And too high carbon left also can not be by largely adding big granularity
Block Jiao realizes suitable Thermal to adjust, the difficulty of this increase arc-covering slag operation.Therefore the carbon left control of reducting pellet
For 2~5%, electric furnace smelting is conducive to operate, the percentage is weight percentage.
Reduction process of the present invention replaces rotary kiln as reduction apparatus from rotary hearth furnace, the body of heater rotated compared to rotary kiln,
Rotary furnace bottom remains static, therefore low to the intensity requirement of green pellets；Rotary hearth furnace is not in the knot that rotary kiln is produced
Phenomenon is enclosed, it is low to the component requirements of raw material, and do not need frequent blowing out to clear up, operating rate is higher；And rotary hearth furnace reduction temperature
Degree is high, and reduction rate is fast, and burnup is low compared with rotary kiln by more than 15%.
(5) smelt
Reducting pellet made from step (4) is cooled to 50~300 DEG C, with semi-coke block, molten of the granularity for 10~30mm
Agent dispensing, is added into closed electric furnace, carries out smelting obtained high carbon ferro-chrome product at 1650~1700 DEG C.
Wherein, the flux is one or both of silica, lime.Requirement to silica and lime is respectively such as the He of table 2
Shown in table 3, percentage therein is weight percentage.
The silica raw material of table 3
The lime raw material of table 4
, it is necessary to which by the water content control of semi-coke block in the range of≤1%, the percentage is before electric furnace smelting is entered
Percentage by weight.Moisture in semi-coke block has no benefit to electric furnace smelting.The semi-coke block of overly moist falls into the metal of liquid and melted
In slag, situations such as easily causing splash is unfavorable for normal smelt and produced.So ferrochrome smelting need to strictly control feed stock for blast furnace
Moisture.
In electric furnace smelting, Thermal is relevant with semi-coke volume in unit volume furnace charge, i.e. the particle size influences of semi-coke are arrived
Thermal.In the case where semi-coke total amount is constant, with the increase of semi-coke granularity, Thermal diminishes, and electrode is difficult
Underthrust；And granularity diminishes, Thermal becomes big, and furnace charge air permeability is deteriorated, though electrode can underthrust, occur in stove scaling loss,
Situations such as thorn fire, grume material, also it is unfavorable for the arc-covering slag operation of electric furnace.So to regulate charging resistance, electrode is inserted deeply,
Also ensure that semi-coke amount and furnace charge needed for reducing have good gas permeability, the semi-coke of selection suitable particle size is necessary.
The semi-coke block of present invention selection 10~30mm granularities, not only contributes to electrode underthrust, and also help increase electricity
The gas permeability of stove furnace charge, these are all conducive to the operational control of electric furnace.
The reducting pellet temperature come out from rotary hearth furnace is high (900~1150 DEG C), is easily aoxidized after ingress of air, reduces
Degree is reduced.Reducting pellet directly hot sending can be realized to electric furnace, but on the one hand be limited by traffic conditions such as drops, the opposing party
Also influence pelletizing is directly heat-fed for the maintenance and maintenance of face electric furnace.In addition, the transporting equipment investment of high-temperature material and operating cost
Greatly.Therefore, high temperature reduction pelletizing requires cool to 50~300 DEG C.
The flux dispensings such as the reducting pellet of cooling and qualified coke, silica, after through adding closing burried arc furnace, pass through
Electrochemical reaction in stove produces ferrochrome.
The general principle of electric furnace process smelting high carbon ferrochrome is the oxide of chromium and iron in reduction with carbon chromite under high temperature, its
Key reaction has：
2/3Cr2O3+ 2C=4/3Cr+2CO Δ G=123970-81.22T T=1523K
2/3Cr2O3+26/9C=4/9Cr3C2+ 2CO Δ G=1144010-83.05T T=1373K
2/3Cr2O3+ 18/7C=4/21Cr7C3+ 2CO Δ G=115380-82.09T T=1403K
2/3Cr2O3+ 54/23C=4/69Cr23C6+ 2CO Δ G=118270-81.75T T=1448K
From the above reaction, it is seen that carbon reduction-oxidation chromium generates Cr3C2Start temperature be 1373K, generate Cr7C3's
Reaction start temperature be 1403K, and generate chromium reaction start temperature be 1523K, thus obtained in carbon reducing chrome ore be
The carbide of chromium, rather than crome metal.Therefore, carbon containing higher high carbon ferro-chrome, and height carbon containing in ferrochrome be can only obtain
Depending on reaction temperature.The high carbide of the generation phosphorus content carbide lower than generation phosphorus content is easier.
In actual production, furnace charge first has part chrome ore to generate Cr with coke gasification reaction in heating process3C2, with furnace charge temperature
Degree rise, most of chrome ore generates Cr with coke gasification reaction7C3, temperature further raises, Cr2O3Refining decarburization is played to alloy to make
With.
Iron oxide reduction reaction start temperature is lower than chrome green reduction start temperature, therefore the iron oxide in chrome ore exists
Just sufficiently it is reduced out under lower temperature, and is dissolved each other with chromium carbide, constitutes double carbide, reduce the fusing point of alloy.
Simultaneously as chromium and the mutual phased soln of iron so that reduction reaction is more easy to carry out.
As the Cr in chromite2O3After being reduced with FeO, remaining main oxides are MgO and Al2O3, both oxidations
The fusing point of thing is very high, it is necessary to plus flux is to reduce its fusing point, could smoothly be flowed out out of stove.
The fusing point of high carbon ferro-chrome is up to more than 1773K, in order to ensure to have high reaction speed and make the alloy of generation smooth
Iron separation is discharged and looked on ground out of stove, it is necessary to make electric furnace Control for Kiln Temperature in more than 1923K.
Can only be burnt using block in the smelting process of general high carbon ferro-chrome, and reduction can not be used as by the use of semi-coke end or fine coal
Agent.Fine coal is the raw material waste products that semi-coke is produced, and semi-coke end is the byproduct of semi-coke production, and both applications are narrow, industrial valency
Value is small.Can be by the use of semi-coke end or fine coal as reducing agent, so as to reduce electric furnace smelting in rotary hearth furnace pre-reduction of the present invention
Block needed for refining is burnt, realizes the comprehensive utilization to coal resources.
Because reducting pellet has certain prereduction and containing a small amount of carbon, it is possible to improve electric furnace yield,
Save block Jiao consumption, substantially reduce melting electric consumption, energy-saving effect is notable.Pelletizing direct hot charging enters electric furnace, and electric furnace smelting power consumption~
2000kw ﹒ h/t.At present, country will increase the dynamics for carrying out highly energy-consuming trade step price or punitive electricity price, therefore this hair
The bright economic benefit to smelting high carbon ferrochrome enterprise is self-evident.
To solve environmental pollution, high-carbon chrome iron for smelting factory both domestic and external tends to open electric furnace being changed to totally-enclosed electric furnace.
Totally-enclosed electric furnace can farthest recycle CO ratios in coal gas, coal gas and be more than 70%.General totally-enclosed electric furnace coal gas into
Divide as shown in table 5, percentage therein is percent by volume.
Table 5
| Composition | CO | CO2 | H2 | H2O | N2 |
| % | 87 | 5 | 4 | 0.4 | 3.6 |
The high carbon ferro-chrome of the present invention and the combined producing process of semi-coke, in addition to off-gas recovery utilize step：By retort
The coal gas of recovery delivers to vertical gas chamber after purification, and coal gas is transported to other users after gas chamber voltage stabilizing；Electric furnace smelting
The tail gas of gained is by delivering to vertical gas chamber after dust separation, coal gas is after gas chamber voltage stabilizing, and a part is by pipeline by coal
Pneumatic transmission enters rotary hearth furnace burning, and a part is transported to other users.
Embodiment
The implementation and the use of equipment of the method for the present invention, people in the art are illustrated below by specific embodiment
Member is it should be appreciated that this is understood not to the limitation to scope of the invention as claimed.Embodiment
Low-disintegration coal used in the present embodiment is jet coal, and jet coal and ferrochrome fine ore are conventional commercial raw material, its chemistry
Respectively as shown in table 6 and table 7, percentage therein is weight percentage composition.
The chemical composition of the jet coal of table 6
| Composition | Moisture | Ash content | Fugitive constituent | Fixed carbon | Full sulphur |
| % | 3.7 | 5.8 | 35.7 | 54.4 | 0.4 |
The chemical composition of the ferrochrome fine ore of table 7
| Title | Cr2O3 | FeO | SiO2 | Al2O3 | MgO | CaO | H2O | P |
| % | 41.3 | 13.02 | 11.45 | 12.18 | 19.32 | 1.5 | ~3 | 0.007 |
Flux used is silica in the present embodiment, from conventional purchased in market.SiO in the silica2Content is 97.8%, Al2O3
Content is 0.8%, and the percentage is weight percentage.The granularity of silica is 10~80mm, wherein<20mm's is not more than 5%.
(1) raw material prepares
By jet coal crushing and screening, it is 30~80mm lump coal and granularity ＜ 30mm fine coal to obtain granularity.
Prepare granularity<10mm ferrochrome fine ore.
(2) preparation of semi-coke
Retort in semi-coke production uses internal thermal upright stove.Lump coal is sent into above internal thermal upright stove by belt
Coal store, be gradually reduced and carry out pyrogenation and carbonization into internal thermal upright stove and obtain semi-coke.The thermal source of pyrolysis of coal destructive distillation is to turn bottom
Flue gas in stove and oxygen concentration are to return in 1200 DEG C of high-temperature flue gas, retort for 99% temperature that produces of pure oxygen burning
40% more than the coal gas amount that the coal gas amount of receipts is reclaimed than conventional internal thermal upright stove.
It is 83.7% that carbon content is fixed in gained semi-coke, and ash content is 14.8%, and volatilization is divided into 1.5%, and the percentage is
Percentage by weight.
(3) pressure ball
By granularity<30mm fine coal and granularity<3mm semi-coke end is 1 according to the mass ratio at semi-coke end and fine coal:15 ratio
Example carries out being mixed to prepare carbon reducing agent.Ferrochrome fine ore and carbon reducing agent are separately dried to water content≤4% and water content
It is 8% ratio of ferrochrome fine ore quality by ferrochrome fine ore and carbon according to the amount of allocating of fixed carbon in carbon reducing agent after≤3%
Plain reducing agent is mixed (mixed carbon comtent is calculated by C/O=0.7), and is ground to particle of the granularity less than 0.074mm more than 65%.
Binding agent molasses and water that addition is ferrochrome fine ore quality 1% are added, it is 5%, a diameter of 20mm life that moisture, which is made,
Pelletizing, it is described to be very weight percentage.
(4) reduce
Obtained green pellets is directly loadable into the rotary hearth furnace that furnace bottom thickness of feed layer is 20mm and carries out high-temperature roasting reduction,
Temperature is reductase 12 5min at 1350 DEG C, and reducting pellet is made.Wherein total degree of metalization of reducting pellet is 50%, and carbon left is
4%.
(5) smelt
Obtained reducting pellet is cooled to 50 DEG C, proportioning station is transported to by chain scraper conveyor, with obtained semi-coke block
With silica dispensing, it is continuously added to through expects pipe in closing burried arc furnace, smelting system is carried out in the case where furnace temperature is 1650~1700 DEG C
Obtain high carbon ferro-chrome product 1#.
(6) off-gas recovery is utilized
Vertical gas chamber will be delivered to after reclaiming the purification such as tar, desulfurization from the coal gas for reclaiming retort, coal gas is by vertical
Other users are delivered to after gas chamber voltage stabilizing.
By tail gas obtained by electric furnace smelting by delivering to vertical gas chamber voltage stabilizing after dust separation, a part is delivered to by pipeline to be turned
Bottom stove burning a, part delivers to other users.
The present invention replaces part of coke with fine coal, saves 40% coke.Power consumption during electric furnace smelting is
2400kw ﹒ h/t, and the output increased of the process 30%.
Comparative example
The raw materials used source of this comparative example is identical with the raw material sources of embodiment 1.
(1) raw material prepares
By jet coal crushing and screening, the lump coal that granularity is 30~80mm is obtained.Granularity ＜ 30mm fine coal is low as fuel
Valency is sold.
Ferrochrome fine ore is sieved and obtains lump ore and granularity that granularity is 10~100mm<10mm fine ore.Fine ore can not be direct
As the raw material of closed electric furnace, so the fine ore after screening is discarded and banked up.
(2) preparation of semi-coke
The conventional retort of retort in semi-coke production.Lump coal is sent into retort by belt, in the case where temperature is 700 DEG C
Pyrogenation and carbonization obtains semi-coke.
Semi-coke product obtains what the block that granularity is 10~30mm was smelted as TAP HOLE OF HIGH CARBON FERROCHROMIUM by crushing and screening again
Raw material.Semi-coke block enters to need heat drying before electric furnace smelting to moisture≤1%.Granularity is used as fuel less than 30mm semi-coke products
Undersell.
(3) electric furnace smelting
The semi-coke block and granularity that the ferrochrome lump ore 100kg for being 10~100mm by granularity, granularity are 10~30mm be 10~
80mm silica is mixed, by Belt Conveying into closed electric furnace, is smelted at 1650~1700 DEG C and high carbon ferro-chrome product is made
2#。
In this comparative example, ferrochrome lump ore obtains high carbon ferro-chrome by electric furnace by melting and reducing completely.Therefore, high carbon ferro-chrome
Smelting energy consumption is higher, and the power consumption of electric furnace smelting is about 3400kw ﹒ h/t.
The foregoing description of the disclosed embodiments, enables those skilled in the art to realize or using the present invention.To this
A variety of modifications of a little embodiments will be apparent for a person skilled in the art, and generic principles defined herein can
Without departing from the spirit or scope of the present invention, to realize in other embodiments.Therefore, the present invention will not be limited
It is formed on the embodiments shown herein, and is to fit to consistent with features of novelty with principles disclosed herein most wide
Scope.
Claims (10)
1. a kind of combined producing process of high carbon ferro-chrome and semi-coke, the technique comprises the following steps：
(1) raw material prepares：Prepare coal and ferrochrome fine ore as the granularity of raw material, wherein ferrochrome fine ore<10mm；
(2) preparation of semi-coke
Semi-coke is made for pyrogenation and carbonization in 30~80mm lump coal feeding retort in granularity in coal, wherein, the temperature of pyrogenation and carbonization
Spend for 950~1100 DEG C；In gained semi-coke product, granularity is smelted for 10~30mm block for TAP HOLE OF HIGH CARBON FERROCHROMIUM, granularity<
Green pellets matches somebody with somebody carbon during 3mm semi-coke end is produced for high carbon ferro-chrome；
(3) pressure ball
Ferrochrome fine ore and carbon reducing agent are separately dried the mixed grinding to water content≤4% and water content≤3%, addition is viscous
Agent and water are tied, it is 5~7%, a diameter of 20~40mm green pellets that moisture, which is made, the percentage is weight percentage；
Wherein, the carbon reducing agent is granularity<30mm fine coal and granularity<The mixture at 3mm semi-coke end, semi-coke end and powder
The mass ratio of coal is 1:1~40；
(4) reduce
Green pellets made from step (3) is directly loadable into rotary hearth furnace and carries out high-temperature roasting reduction, reducting pellet is made；Wherein, also
The former time is 25~85min, and reduction temperature is 1100~1350 DEG C；
(5) smelt
Reducting pellet made from step (4) is cooled to 50~300 DEG C, with granularity is 10~30mm semi-coke block, flux matches somebody with somebody
Material, is added into closed electric furnace, carries out smelting obtained high carbon ferro-chrome product at 1650~1700 DEG C；
Wherein, the origin of heat of retort uses purity in rotary hearth furnace described in step (2)>The height that 90% oxygen combustion is produced
Warm flue gas.
2. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that institute in step (2)
State the high-temperature flue gas that the origin of heat of retort uses purity to be produced for 99% oxygen combustion in rotary hearth furnace.
3. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that the technique also includes
(6) off-gas recovery utilizes step：
Coal gas after retort reclaiming clean, voltage stabilizing is delivered to other users；
After the purification of tail gas removing dust, voltage stabilizing obtained by electric furnace smelting, a part delivers to rotary hearth furnace burning, and a part delivers to other use
Family.
4. the combined producing process of the high carbon ferro-chrome and semi-coke according to claim any one of 1-3, it is characterised in that step
(1) coal described in is lower-grade metamorphic bituminous.
5. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that in step (3), press
Amount of allocating according to fixed carbon in carbon reducing agent is the 8~14% of ferrochrome fine ore quality, and ferrochrome fine ore is entered with carbon reducing agent
Row mixing, is ground to particle of the granularity less than 0.074mm more than 65%.
6. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that in step (3), institute
One or more of the binding agent in bentonite, waterglass, molasses, spent pulping liquor are stated, the addition of binding agent is ferrochrome powder
The 1~6% of mineral amount.
7. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that in step (4), control
The carbon left of reducting pellet processed is 2~5%, and the percentage is weight percentage.
8. the combined producing process of high carbon ferro-chrome according to claim 1 and semi-coke, it is characterised in that in step (5), institute
It is one or both of silica, lime to state flux.
9. the combined producing process of high carbon ferro-chrome according to claim 8 and semi-coke, it is characterised in that the grain of the silica
Spend for 10-80mm, wherein granularity<20mm silica is not more than 5%；By weight percentage, SiO in silica2Content >=97%,
Al2O3Content<1%.
10. the combined producing process of high carbon ferro-chrome according to claim 8 and semi-coke, it is characterised in that the lime
Granularity is 20-80mm；By weight percentage, CaO content >=85% in lime, P content≤0.02%, SiO2Content≤3%.
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| CN105908061B (en) * | 2016-06-12 | 2018-01-02 | 江苏省冶金设计院有限公司 | A kind of method for producing high carbon ferro-chrome |
| CN106756380B (en) * | 2016-11-28 | 2018-12-14 | 江苏大学 | A method of so that high carbon ferro-chrome solid state decarbonization is produced low-carbon ferrochromium with rotary hearth furnace |
| CN107385206B (en) * | 2017-07-25 | 2019-07-05 | 中冶东方工程技术有限公司 | Ferrochrome raw material pretreatment process |
| CN108977607A (en) * | 2018-08-06 | 2018-12-11 | 王德清 | A kind of joint smelting process of high carbon ferro-chrome and forsterite |
| CN109097651B (en) * | 2018-08-09 | 2019-06-28 | 徐州宏阳新材料科技有限公司 | A kind of low-phosphorous high carbon ferro-chrome and its smelting process |
| CN111893296B (en) * | 2020-09-10 | 2024-03-29 | 山西通才工贸有限公司 | Hot-pressed scrap steel carburetion method and device thereof |
| CN114182089B (en) * | 2021-11-26 | 2024-04-16 | 南京南钢产业发展有限公司 | Sintering method of semi-coke raw material |
| CN115806841B (en) * | 2022-11-28 | 2024-07-09 | 中南大学 | Method for efficiently preparing hydrogen-rich gas by using biomass or low-rank coal |
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