CN103397175B - Method for improving compressive strength of alkali pellets prepared with limestone - Google Patents
Method for improving compressive strength of alkali pellets prepared with limestone Download PDFInfo
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- CN103397175B CN103397175B CN201310311440.4A CN201310311440A CN103397175B CN 103397175 B CN103397175 B CN 103397175B CN 201310311440 A CN201310311440 A CN 201310311440A CN 103397175 B CN103397175 B CN 103397175B
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Abstract
The invention relates to a method for improving the compressive strength of alkali pellets prepared with limestone. The method comprises the following steps of: grinding the limestone into superfine particle size of less than 3 microns, adding the limestone powder of superfine particles into pellet concentrate powder with the particle size of less than 74 microns, adding water, and mixing uniformly in a mixer, wherein an adhesive is not used in proportioning; and pelletizing the uniform mixture, and roasting the screened fresh pellets. The roasting process comprises drying, preheating, roasting, soaking and cooling; and oxygen enrichment is performed in the preheating and roasting processes, the oxygen content in the preheating process is kept between 12 and 15 percent, and the oxygen content in the roasting process is kept between 10 and 12 percent. The problem that the compressive strength of the alkali pellets prepared with the limestone obviously declines is effectively solved through the measures of grinding of the limestone, oxygen enrichment in the roasting process and the like.
Description
Technical field
The present invention relates to blast furnace ironmaking iron ore pellets production technical field, be specifically related to a kind of method that the pellet ultimate compression strength of Wingdale is joined in raising.
Background technology
Pellet is one of blast furnace ironmaking main raw material, and current China pellet production capacity has reached 200,000,000 tons, but main production is general acidic pellet.Acidic pellet ore is the pellet of natural alkalinity, SiO
2and Al
2o
3higher Deng constituent content, and the content of the alkaline substance such as calcium magnesium is few, uses so can only arrange in pairs or groups with high basicity sinter in blast furnace.Dual alkalinity be more than 0.6% pellet be called Basic Pellets.The advantages such as it is high that Basic Pellets has reductibility, and melt-dropping property is good, but the ultimate compression strength of Basic Pellets is difficult to improve, and especially along with the raising of basicity, the ultimate compression strength of Basic Pellets obviously declines.Major cause is that the alkaline additives such as Wingdale divide heat of desorption at roasting process, and alkali grain more slightly makes iron ores particle disperse, and weakens oxidation and the recrystallize of iron ores particle.Although improve maturing temperature can improve the Basic Pellets ultimate compression strength of joining Wingdale within the specific limits, too high temperature not only increases energy consumption, and produces too much liquid phase, affects pellet ultimate compression strength on the contrary.The production technique of most domestic pelletizing plant is grate kiln and shaft furnace, if maturing temperature is too high, not only refractory life shortens, and the problems such as ring formation appear in rotary kiln, and this is also that the domestic pelletizing plant of restriction produces one of factor of Basic Pellets.
Summary of the invention
In order to solve above technical problem, the invention provides a kind of method that the Basic Pellets ultimate compression strength of Wingdale is joined in raising, the problem that after the method effectively overcomes and joins Wingdale, pellet ultimate compression strength obviously declines.
The present invention is achieved through the following technical solutions:
A method for the Basic Pellets ultimate compression strength of Wingdale is joined in raising, comprises the steps:
Wingdale is ground to the ultra-fine grade of less than 3 μm, the limestone powder of ultra-fine grain is allocated in the pellet fine ore of less than 74 μm grades, and mixes with mixer; Binding agent is not used in batching;
The material mixed is carried out pelletizing, screens the green-ball produced and carry out roasting;
Roasting process comprises drying, preheating, roasting, soaking and cooling;
In preheating and roasting process, carry out oxygen enrichment, warm oxygen level remains on 12 ~ 15%, and roasting process oxygen level remains on 10 ~ 12%.
In technique scheme, the mass percent of described pellet fine ore and described limestone powder is 92 ~ 97:3 ~ 8.
In technique scheme, described fine ore iron-holder more than 80%.
In technique scheme, the green-ball screening the 8 ~ 16mm produced carries out roasting.
In technique scheme, the temperature of described preheating controls at 600 ~ 1000 DEG C.
In technique scheme, the temperature of described roasting controls at 1250 ~ 1260 DEG C.
In technique scheme, the time of described preheating and roasting is all 15 minutes.
In technique scheme, the temperature of described soaking controls at 1100 ~ 1150 DEG C.
In technique scheme, described soaking time is 3 minutes.
In technique scheme, the pelletizing after described soaking is cooled to less than 150 DEG C.
The application is ground to the Ultra-fine of less than 3 μm and the oxygen enrichment of preheating and roasting process by making Wingdale, effectively overcomes limestone particle thick, dispersion iron ores particle, affects the problem of iron ores particle oxidation and recrystallize; Oxic process can desalinate rapidly the CO that decomposition of limestone goes out
2gas, and oxygen more than needed enters pelletizing inside by pelletizing hole, increases the oxidation of iron ores particle; Therefore fine grinding and oxygen enrichment step combine the ultimate compression strength that improve pellet, obtain the Basic Pellets of high strength at a lower temperature.
Accompanying drawing explanation
Fig. 1 joins the schema of the method for the Basic Pellets ultimate compression strength of Wingdale for raising that the embodiment of the present invention provides.
Embodiment
Below in conjunction with drawings and Examples, technical scheme of the present invention is described in detail.
Embodiment 1
First Wingdale is ground to 3 μm of grades, then ultra-fine grain limestone powder being allocated into less than 74 μm grade iron-holder is in the fine ore of 86%, and prepare burden by the mass percent of 8:92, mix after batching, mixture moisture controls 8.0%.Then in balling disc, carry out pelletizing, Balling time is 10 minutes.Pelletizing terminates green-ball that rear sieve gets 8 ~ 16mm grade at the temperature of 450 DEG C dry 7 minutes, next preheating 15 minutes at the temperature of 650 DEG C, and warm oxygen enrichment, oxygen level remains on 14%, pelletizing after preheating is at the roasting temperature 15 minutes of 1260 DEG C, roasting process Control for Oxygen Content 12%, then soaking 3 minutes at the temperature of 1150 DEG C.Soaking terminates rear air at room temperature and pellet is cooled to less than 150 DEG C, obtains the ultimate compression strength that measures according to GB GB/T14201-93 " the iron ore pellets compressive strength determination method " Basic Pellets at more than 2800N/P.
Embodiment 2
First Wingdale is ground to 2.5 μm of grades, then fine grain limestone powder is joined less than 74 μm grades, iron-holder is in the fine ore of 85%, and the mass percent of limestone powder and fine ore selects 3:97.Then mix, mixture moisture controls 7.8%.
The material balling disc mixed carries out pelletizing, and Balling time controls 10 minutes.Then sieve with sieve the green-ball getting 8 ~ 16mm granularity and carry out roasting.
Roasting process comprises drying, preheating, roasting, soaking and cooling.The green-ball prepared first at the temperature of 350 DEG C dry 7 minutes, then preheating 15 minutes at the temperature of 750 DEG C, warm oxygen enrichment, oxygen level remains on 12%, pelletizing after preheating is at the roasting temperature 15 minutes of 1250 DEG C, roasting process Control for Oxygen Content 10%, then soaking 3 minutes at the temperature of 1100 DEG C.Soaking terminates rear air at room temperature and pellet is cooled to less than 150 DEG C, obtains the ultimate compression strength that measures according to GB GB/T14201-93 " the iron ore pellets compressive strength determination method " Basic Pellets at more than 2800N/P.
Embodiment 3
First Wingdale is ground to 2 μm of grades, then the limestone powder of ultra-fine grain is allocated into less than 74 μm grades, iron-holder is in the fine ore of 80%, and during batching, the mass percent of limestone powder and fine ore selects 5:95, then carry out mixing and adding water, moisture controlled is 8.0%.
The material balling disc mixed carries out pelletizing, and Balling time is 10 minutes.Sieve with sieve the green-ball getting 8 ~ 16mm grade after pelletizing and carry out roasting.
Roasting process comprises for drying, preheating, roasting and cooling.The green-ball for preparing first at the temperature of 400 DEG C dry 7 minutes, then preheating 15 minutes at the temperature of 800 DEG C, warm oxygen enrichment, oxygen level remains on 14%, the roasting 15 minutes at 1250 DEG C of pelletizing after preheating, Control for Oxygen Content 11%, the soaking 3 minutes at the temperature of 1150 DEG C of the pelletizing after roasting.Finally with air at room temperature, pellet is cooled to less than 150 DEG C, obtains the ultimate compression strength that measures according to GB GB/T14201-93 " the iron ore pellets compressive strength determination method " Basic Pellets at more than 2800N/P.
Embodiment 4
First Wingdale is ground to 1.5 μm of grades, then ultra-fine grain limestone powder is allocated into less than 74 μm grades, iron-holder is in the fine ore of 80%, and prepare burden by the mass percent of 8:92, mix after batching, mixture moisture controls 8.0%.Then in balling disc, carry out pelletizing, Balling time is 10 minutes.Pelletizing terminates green-ball that rear sieve gets 8 ~ 16mm grade at the temperature of 450 DEG C dry 7 minutes, next preheating 15 minutes at the temperature of 850 DEG C, and warm oxygen enrichment, oxygen level remains on 15%, pelletizing after preheating is at the roasting temperature 15 minutes of 1260 DEG C, roasting process Control for Oxygen Content 12%, then soaking 3 minutes at the temperature of 1150 DEG C.Soaking terminates rear air at room temperature and pellet is cooled to less than 150 DEG C, obtains the ultimate compression strength that measures according to GB GB/T14201-93 " the iron ore pellets compressive strength determination method " Basic Pellets at more than 2800N/P.
Because the present invention uses the Wingdale of ultra-fine grain, the binding agent itself just had, therefore not needing to join other binding agents such as wilkinite when preparing burden, having saved production cost.By making Wingdale be ground to the Ultra-fine of less than 3 μm and the oxygen enrichment of preheating and roasting process, effectively overcoming limestone particle thick, dispersion iron ores particle, affecting the problem of iron ores particle oxidation and recrystallize; Oxic process can desalinate rapidly the CO2 gas that decomposition of limestone goes out, and oxygen more than needed enters pelletizing inside by pelletizing hole, increases the oxidation of iron ores particle; Therefore fine grinding and oxygen enrichment step combine the ultimate compression strength that improve pellet, obtain the Basic Pellets of high strength at a lower temperature.
It should be noted last that, above embodiment is only in order to illustrate the technology implementation scheme of this material but not to limit, although with reference to preferred embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not departing from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.
Claims (3)
1. a method for the Basic Pellets ultimate compression strength of Wingdale is joined in raising, it is characterized in that: comprise the steps:
Wingdale is ground to the ultra-fine grade of less than 3 μm, the limestone powder of ultra-fine grain is allocated in the fine ore of less than 74 μm grades, add water, and mix with mixer; Binding agent is not used in batching;
The material mixed is carried out pelletizing, screens the green-ball produced and carry out roasting;
Roasting process comprises drying, preheating, roasting, soaking and cooling;
In preheating and roasting process, carry out oxygen enrichment, warm oxygen level remains on 12 ~ 15%, and roasting process oxygen level remains on 10 ~ 12%; The mass percent of described fine ore and described limestone powder is 92 ~ 97:3 ~ 8;
Described fine ore iron-holder is more than 80%;
The temperature of described preheating controls at 600 ~ 1000 DEG C;
The time of described preheating and roasting is all 15 minutes;
The temperature of described soaking controls at 1100 ~ 1150 DEG C, and soaking time is 3 minutes.
2. the method for the Basic Pellets ultimate compression strength of Wingdale is joined in raising as claimed in claim 1, it is characterized in that: the green-ball screening the 8 ~ 16mm produced carries out roasting.
3. the method for the Basic Pellets ultimate compression strength of Wingdale is joined in raising as claimed in claim 1, it is characterized in that: the pelletizing after described soaking is cooled to less than 150 DEG C.
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|---|---|---|---|
| CN201310311440.4A CN103397175B (en) | 2013-07-23 | 2013-07-23 | Method for improving compressive strength of alkali pellets prepared with limestone |
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| CN201310311440.4A CN103397175B (en) | 2013-07-23 | 2013-07-23 | Method for improving compressive strength of alkali pellets prepared with limestone |
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| CN103397175B true CN103397175B (en) | 2015-03-25 |
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| CN109371232B (en) * | 2018-11-28 | 2020-03-27 | 山西太钢不锈钢股份有限公司 | Method for reducing the expansion rate of pellets |
| CN113151672A (en) * | 2021-04-23 | 2021-07-23 | 铜陵博锋实业有限公司 | Method for improving compression strength of alkaline pellets prepared with limestone |
| CN115368042B (en) * | 2022-08-19 | 2023-09-08 | 深圳市考拉生态科技有限公司 | Method for producing porous wollastonite spheres by using fluorine gypsum and quartz waste stone |
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| US4135913A (en) * | 1972-10-27 | 1979-01-23 | The International Nickel Company, Inc. | Thermal concentration of non-ferrous metal values in sulfide minerals |
| JP2006291320A (en) * | 2005-04-13 | 2006-10-26 | Sumitomo Metal Mining Co Ltd | Method for pelletizing rotary kiln dust |
| CN102242251B (en) * | 2011-06-22 | 2013-11-06 | 攀钢集团有限公司 | Alkaline V-Ti pellet and preparation method thereof |
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Address after: 100041 Shijingshan Road, Beijing, No. 68, No. Patentee after: Shougang Group Co. Ltd. Address before: 100041 Shijingshan Road, Beijing, No. 68, No. Patentee before: Capital Iron & Steel General Company |
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