CN102796839A - Technique for producing direct reduced iron and synchronously performing desulfurization through reduction roasting of sulfate slag - Google Patents
Technique for producing direct reduced iron and synchronously performing desulfurization through reduction roasting of sulfate slag Download PDFInfo
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- CN102796839A CN102796839A CN2012103117412A CN201210311741A CN102796839A CN 102796839 A CN102796839 A CN 102796839A CN 2012103117412 A CN2012103117412 A CN 2012103117412A CN 201210311741 A CN201210311741 A CN 201210311741A CN 102796839 A CN102796839 A CN 102796839A
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Abstract
The invention relates to a technique for producing direct reduced iron and synchronously performing desulfurization through reduction roasting of sulfate slag, belonging to the field of resource utilization. According to the invention, one-step direct reduction roasting is performed on a secondary resource sulfate slag to obtain direct reduced iron powder, and meanwhile, a desulfurizer is added to remove sulfur in the sulfate slag. The invention is characterized in that compared with other methods, the technique is simple, and low-cost coal is directly used as the reducer; the added desulfurizer is a mixture of sodium carbonate and calcium carbonate; by adding the reducer and the desulfurizer and controlling the roasting temperature and time, iron recovery and sulfur element removal can be synchronously completed, and the harmful element sulfur is prevented from entering the product while the grade and the recovery rate of the direct reduced iron are ensured. Thus, the direct reduced iron powder of which the iron grade is 90% or above is finally obtained, the iron recovery rate is greater than 90% in general, the sulfur removal rate is greater than 96%, and the sulfur content of the obtained direct reduced iron is below 0.1%.
Description
Technical field
The invention belongs to utilization of resources field, relate to a kind of sulfate slag that uses and be raw material, add sweetening agent and reductive agent, produce the process method of dri powder and synchronized desulfuring with direct reduction calcination method.This technology mainly is to be reductive agent with the coal, and in sulfate slag, adds sweetening agent, adopts the iron in direct reducing roasting-magnetic selection method reclaim(ed) sulfuric acid slag then and realizes the process method of synchronized desulfuring.
Technical background
Along with the continuous development of China's steel industry, also growing and the situation that supply falls short of demand occurred to the demand of fe source, so some unmanageable relatively iron content secondary resources such as sulfate slag have had the value of very big development and use.Sulfate slag is to make the waste residue that produces in sulfuric acid or the sulfurous acid process with pyrite, is generally the powdery opening material, the big and undefined structure of water regain, and the staple of some representational sulfate slags is seen shown in the table 1:
The staple of some representational sulfate slags of table 1
Can see that by table 1 TFe content is about 20% ~ 60% in the sulfate slag, in addition, also contain non-ferrous metals such as Cu, Pb, Zn, Co in some sulfate slag.Impurity is mainly with SiO
2Be main, account for 5% ~ 40%, Al
2O
3Account for 1% ~ 5%, contain CaO, MgO etc. in addition.Although Fe content is higher in the sulfate slag, also very high in the sulfate slag to making steel the content of deleterious element S, reach 1% ~ 2% even higher usually, because be difficult to reduce the content of S, sulfate slag can not get good development and use always for a long time.
The treatment process that from sulfate slag, reclaims iron at present mainly contains: beneficiating method, magnetizing roasting method and chlorinating roasting etc.Beneficiating method is to adopt the oxide compound of iron in the method reclaim(ed) sulfuric acid slag of traditional magnetic separation, gravity treatment, flotation and combined process flow (to be mainly Fe
3O
4And Fe
2O
3), but this method is applicable to black slag more, promptly contains Fe
3O
4The slag that content is more, and S content is higher in the concentrate that obtains, to follow-up ironmaking and all deleterious impact of making steel.The magnetizing roasting process can be with the Fe of weak magnetic in the sulfate slag
2O
3Be reduced to ferromagnetic Fe
3O
4, reclaim through low intensity magnetic separation then, but the iron recovery that this kind method obtains is low, and still can not well solves the high problem of S content.Chlorinating roasting is that this method can make the non-ferrous metal in the sulfate slag evaporate with the muriate form, thereby reclaims metals such as Cu, Pb, Au, Ag with sulfate slag and lime and chlorizating agent mixed pelletizing oven dry roasting in shaft furnace; Pelletizing after the roasting remakes and is iron-smelting raw material; The advantage that adopts this method is to reclaim multiple metal, but foreign matter content is higher in the iron content pelletizing that obtains, and needs further to handle; So complex process, processing cost is than higher.
More than these process methodes when handling sulfate slag, all have certain drawback, especially on the low side and to form the concentrate grade that complicated sulfate slag often obtains low for iron-holder, foreign matter content is high, iron recovery is low.Therefore at present except a small amount of probe into Processing high Iron and Sulfur acid sludge can utilize, most of sulfate slag does not find and effectively utilizes method, can only store up or discarded, causes the significant wastage of resource.
Summary of the invention
The present invention is directed to existing sulfate slag can not efficient recovery iron and the problem of desulfurization difficulty; With the coal is reductive agent; Through adding sweetening agent sulfate slag is carried out direct reducing roasting; The iron that product after the roasting reclaims wherein through the ore grinding magnetic separation obtains the dri powder, can reduce the wherein content of sulphur simultaneously, thereby reaches the purpose of simplifying technical process, reducing investment outlay, realize comprehensive utilization of resources.
The process method of dri synchronized desulfuring is produced in a kind of sulfate slag reducing roasting; Its key step is: add sweetening agent and abundant mixing when in sulfate slag, adding an amount of reductive agent; Mixed material carries out direct reducing roasting, and making wherein, the oxide compound of most of iron is reduced to metallic iron.Carbon reaction in direct reducing roasting process in a part of sulphur and the reductive agent generates the gasiform carbonylsulfide and is able to remove, and the reactive desulfurizing agent of another part and interpolation generates sulfurated lime or the sulphur rankinite that does not have magnetic, in the magnetic separation process, removes.Gangue mineral in sweetening agent and the sulfate slag reacts simultaneously, destroys the package structure between the mineral, makes the dri particle be easier to monomer dissociation.Sulfate slag after the roasting is through ore grinding and low intensity magnetic separation, and the metallic iron that reduction is obtained gets into the low intensity magnetic separation concentrate, obtains high-grade dri powder, and non-magnetic sulfurated lime or sulphur rankinite then get into mine tailing and be able to remove.The grade and the recovery of iron all are higher than 90% in the dri product that obtains through this technology, and the removal of sulphur rate can reach more than 96%, and the sulphur content in the dri that obtains is lower than 0.1%.
Concrete steps and the condition of implementing this method are: the first step adds reductive agent and sweetening agent in sulfate slag.Used reductive agent staple is a coal; The staple of sweetening agent is the mixture of yellow soda ash and lime carbonate; Both mixing quality ratios are 1: (1 ~ 2); The interpolation mass ratio of sulfate slag, reductive agent and sweetening agent is 1: (0.2 ~ 0.4): (0.025 ~ 0.07), the coal consumption is generally 20%～40% of sulfate slag quality, and doctor solution consumption is generally about 2.5%～7% of sulfate slag quality; The reductive agent and the doctor solution consumption ratio of different places of production sulfate slag are different, and concrete consumption can be confirmed through test.
Second step, more than after three kinds of compositions mix, be warming up to 1150 ~ 1200 ℃, at this roasting temperature 40～80min, concrete roasting time is adjusted according to the different in kind of sulfate slag; Under the acting in conjunction of reductive agent and sweetening agent; The oxide compound of the iron in the sulfate slag is reduced to the metallic iron of simple substance state; And the pyrite reaction generates sulfurated lime or sulphur rankinite in sweetening agent and the sulfate slag; Another part sulphur is directly generating volatile carbonylsulfide in the reducing roasting process in the sulfate slag, and the embedding cloth between mineral is destructurized simultaneously.
The 3rd step, carry out mill ore magnetic selection behind the roasting product cool to room temperature, ore grinding mass concentration 60%, the hop count of grinding fineness and mill ore magnetic selection decides according to different sulfate slag character, usually grinding fineness to reach-0.074mm accounts for more than 90%.Adopt low intensity magnetic separation to sort, magneticstrength is 110 ~ 150KA/m.
Utilize process method of the present invention, can effectively from sulfate slag, reclaim iron, the dri product grade and the recovery can reach more than 90%, and the removal of sulphur rate can reach more than 96%, and the sulphur content of dri product is lower than 0.1%.Thereby realized reclaiming in the sulfate slag purpose of iron and synchronized desulfuring.
Compare with existing method, the inventive method has following characteristics: 1. sulfate slag does not also have effective treatment process at present, and sulphur wherein is difficult to remove.Can when reclaiming iron, remove element sulphur after adopting present method, and obtain the iron grade greater than 90% dri powder; What 2. reclaim the dependence of iron synchronized desulfuring is the combination of reductive agent and sweetening agent, and the kind of used reductive agent of this technology and sweetening agent is simple, and consumption is few, and the source is wide, and cost is low; 3. the high efficiente callback of iron in the sulfate slag can be realized, and the secondary resource utilization ratio can be significantly improved; 4. not only can guarantee the recovery of iron, can also remove sulphur simultaneously, realize the removal of sulphur rate more than 96%, make sulphur content in the dri product reach the standard of steel-making requirements; 5. the reduced iron powder of iron content more than 90% that obtain of this technology, the raw produce that can be used as steel-making is sold, and can realize higher economic benefit.
Description of drawings
Accompanying drawing 1 is depicted as the technical process that the dri synchronized desulfuring is produced in sulfate slag reducing roasting-magnetic separation.
Embodiment
For describing the present invention better, with embodiment method provided by the invention is described in further detail below in conjunction with accompanying drawing.
Embodiment 1
Certain sulfate slag iron content 51.51%, sulphur content are 1.22%, and iron-bearing mineral is mainly magnetite, rhombohedral iron ore and pyrite, and gangue mineral is a forsterite, and sulphur mainly exists with pyritous form.The reducing roasting condition of producing dri powder synchronized desulfuring is: the consumption of reductive agent brown coal is 30% of a sulfate slag quality; Doctor solution consumption is 5% of a sulfate slag quality; Desulfurizer therefor is the mixture of yellow soda ash and lime carbonate, and both mixing quality ratios are 1:1.2; In retort furnace, be warming up to 1200 ℃ behind the above material mixing, and under this temperature reducing roasting 60min; Product after the roasting carries out the two stage grinding magnetic separation after being cooled to room temperature, and the primary grinding fineness accounts for 80% for-0.074mm, and the secondary grinding fineness accounts for 95% for-0.074mm; Under magneticstrength 111.5kA/m, carry out two sections low intensity magnetic separations.Can obtain iron grade 90.13%, the dri powder of iron recovery 95.06%, the removal of sulphur rate reaches 96.72%, and sulphur content is 0.04% in the reduced iron powder.
Embodiment 2
Certain sulfate slag iron content 54.03%, sulfur-bearing 1.74%, iron-bearing mineral is mainly rhombohedral iron ore and pyrite, and major impurity is SiO
2The reducing roasting condition of producing the dri powder is: the consumption of reductive agent brown coal is 25% of a sulfate slag quality; Doctor solution consumption is 7% of a sulfate slag quality, and the mixing quality ratio of yellow soda ash and lime carbonate is 1:1.5 in the desulfurizer therefor; Behind the mixing in retort furnace 1150 ℃ of following reducing roasting 50min, be cooled to after the room temperature in that concentration 60% is levigate and account for 90.21% to granularity-0.076mm, under magneticstrength 140kA/m, carry out a stages of magnetic separation; Concentrate carries out secondary grinding and magnetic separation then, and grinding fineness accounts for 95% for-0.043mm, and the magnetic separation field intensity is 140kA/m; Obtain iron grade 90.47%; The iron powder of iron recovery 92.23%, the content of sulphur is 0.05% in the dri that obtains, and the clearance of element sulphur has been reached 97.13%.
Claims (4)
1. the process method of dri synchronized desulfuring is produced in a sulfate slag reducing roasting; It is characterized in that: with iron grade 40%～60%, the sulfate slag of sulphur content 1%～5% is a raw material, adopts direct reducing roasting-magnetic method to reclaim wherein iron and synchronized desulfuring; At first be reductive agent with the coal, the consumption of reductive agent coal dust the sulfate slag quality 20%～40% between; Add sweetening agent and carry out direct reducing roasting-magnetic separation, desulfurizer therefor is the mixture of yellow soda ash and lime carbonate, and consumption is 2.5%～7.0% of a sulfate slag quality; In direct reducing roasting process; Make the oxide compound of the iron in the sulfate slag be reduced to metallic iron; Making a part of sulphur generate the carbonylsulfide volatilization simultaneously removes; Another part sulphur and sweetening agent generate nonmagnetic sulfurated lime or sulphur rankinite under high temperature reduction atmosphere; Through ore grinding, low intensity magnetic separation magnetic metallic iron is separated with the sulphur rankinite with nonmagnetic sulfurated lime then, obtain the iron grade and the recovery all greater than 90% dri powder, and sulphur obtains in the process of directly reducing roasting and ore dressing removing.
2. the process method of dri synchronized desulfuring is produced in a kind of sulfate slag reducing roasting as claimed in claim 1, and the reduction temperature that it is characterized in that direct reducing roasting is 1150～1200 ℃, recovery time 40～80min.
3. the process method of dri synchronized desulfuring is produced in a kind of sulfate slag reducing roasting as claimed in claim 1, it is characterized in that the sweetening agent that adds is the mixture of yellow soda ash and lime carbonate, and both mass ratios are 1: (1 ~ 2); The effect of sweetening agent is in the process of directly reducing roasting, to react with pyrite or pyrrhotite and gangue mineral; Destroy the embedding cloth and the package structure of mineral in the sulfate slag; Make the iron granule of generation be easier to monomer dissociation; Generate sulfurated lime or sulphur rankinite with the reaction of sulfur-bearing mineral yellow iron ore simultaneously, and the metallic iron in the roasted ore is separated with the sulfurated lime or the sulphur rankinite of sulfur-bearing through the method for ore grinding-magnetic separation.
4. the process method of dri synchronized desulfuring is produced in a kind of sulfate slag reducing roasting as claimed in claim 1; It is characterized in that the roasting product after the direct reducing roasting carries out one or more snippets mill ore magnetic selection through behind the naturally cooling in ball mill; The ore grinding mass concentration is 60%, and grinding fineness-0.074mm accounts for more than 90%; Ore milling product magnetic separation under magneticstrength 110 ~ 150KA/m condition obtains the iron grade at the dri powder more than 90%.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103305701A (en) * | 2013-07-02 | 2013-09-18 | 北京神雾环境能源科技集团股份有限公司 | Comprehensive recovery method of sulfuric-acid residue containing gold and silver |
| CN106048209A (en) * | 2016-05-31 | 2016-10-26 | 江苏省冶金设计院有限公司 | Method and system for treating sodium jarosite residue |
| CN112111644A (en) * | 2020-08-31 | 2020-12-22 | 柯柏友 | Method for efficiently recovering gold and silver |
| CN112226564A (en) * | 2020-09-08 | 2021-01-15 | 湖北理工学院 | Method for full resource utilization of sulfuric acid residue and coal ash |
| CN113151628A (en) * | 2021-03-15 | 2021-07-23 | 中国恩菲工程技术有限公司 | Method for producing direct reduced iron from sulfuric acid slag and carbide slag |
| CN113293250A (en) * | 2021-05-21 | 2021-08-24 | 柯柏友 | Efficient recycling method of sulfur concentrate |
Citations (3)
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| CN1924034A (en) * | 2005-09-01 | 2007-03-07 | 中南大学 | Method of producing high grade magnetic concentrate from sulfuric-acid residue composite pellet |
| CN101906499A (en) * | 2009-06-04 | 2010-12-08 | 吴道洪 | Iron-making method for treating sulfate slag by direct reduction, grinding and sorting |
| CN102424875A (en) * | 2011-12-31 | 2012-04-25 | 湖南有色金属研究院 | Method for preparing sponge iron from sulfate cinder |
-
2012
- 2012-08-28 CN CN2012103117412A patent/CN102796839A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1924034A (en) * | 2005-09-01 | 2007-03-07 | 中南大学 | Method of producing high grade magnetic concentrate from sulfuric-acid residue composite pellet |
| CN101906499A (en) * | 2009-06-04 | 2010-12-08 | 吴道洪 | Iron-making method for treating sulfate slag by direct reduction, grinding and sorting |
| CN102424875A (en) * | 2011-12-31 | 2012-04-25 | 湖南有色金属研究院 | Method for preparing sponge iron from sulfate cinder |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103305701A (en) * | 2013-07-02 | 2013-09-18 | 北京神雾环境能源科技集团股份有限公司 | Comprehensive recovery method of sulfuric-acid residue containing gold and silver |
| CN103305701B (en) * | 2013-07-02 | 2015-01-21 | 北京神雾环境能源科技集团股份有限公司 | Comprehensive recovery method of sulfuric-acid residue containing gold and silver |
| CN106048209A (en) * | 2016-05-31 | 2016-10-26 | 江苏省冶金设计院有限公司 | Method and system for treating sodium jarosite residue |
| CN112111644A (en) * | 2020-08-31 | 2020-12-22 | 柯柏友 | Method for efficiently recovering gold and silver |
| CN112226564A (en) * | 2020-09-08 | 2021-01-15 | 湖北理工学院 | Method for full resource utilization of sulfuric acid residue and coal ash |
| CN113151628A (en) * | 2021-03-15 | 2021-07-23 | 中国恩菲工程技术有限公司 | Method for producing direct reduced iron from sulfuric acid slag and carbide slag |
| CN113293250A (en) * | 2021-05-21 | 2021-08-24 | 柯柏友 | Efficient recycling method of sulfur concentrate |
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Application publication date: 20121128 |