CN103045859A - Chromium-iron mineral powder sintering method for stainless steel production - Google Patents

Abstract

The invention provides a chromium-iron mineral powder sintering method for stainless steel production. According to the chromium-iron mineral powder sintering method, pelletization and sintering are carried out after laterite is added to chromium-iron mineral powder; as the laterite and water have good wetting property, the laterite serving as nucleation particles and the chromium-iron mineral powder adhere to each other and grow, and then are pelletized and clustered in a pelletization process, thus solving the problem that the chromium-iron mineral powder is difficult in pelletizaiton; simultaneously, the sintering temperature of chromite can be reduced due to the addition of the laterite, the amount of a liquid phase is increased, the energy consumption is reduced, the rate of finished product and the strength of a sinter are increased, and the problems of difficulty in sintering of the chromium-iron mineral powder, high content of mixed carbon and high energy consumption in the prior art are solved; as compositions of the laterite are similar to that of a smelting slag system, follow-up smelting and slagging working procedures for stainless steel production are not added, the price is relatively low, and the total cost of the stainless steel production can be effectively reduced; and the chromium-iron mineral powder sintering method has the advantages of increasing the economic benefits of enterprises and relieving the energy saving and emission reduction pressure of the enterprises.

Description

A kind of chromite fine ore sintering processing method for stainless steel production

Technical field

The present invention relates to metallurgical engineering technology and environmental protection and energy saving technical field, relate in particular to a kind of chromite fine ore sintering processing method for stainless steel production.

Background technology

China's iron and steel output occupies first place in the world, and stainless demand and production capacity also significantly improve.At present, the stainless steel that uses in the world has 65% ~ 70%, austenitic stainless steel approximately.Chromium nickel be stainless steel account for world's stainless steel output 2/3rds.For guaranteeing stainless steel institute intrinsic corrosiom resistance, steel must contain the nickel content of chromium more than 16%, more than 8%.Chromium and nickel are to produce stainless basic interpolation element.Annual production a large amount of ferrochrome and the ferronickel of needing of China.Because China's chrome ore reserves only 0.15% are the countries of a chromium poorness, therefore annually need a large amount of import chrome ores, externally interdependency reaches more than 95%.

Chromium always forms chromohercynite (FeO.Cr with the iron symbiosis at occurring in nature ₂O ₃), its mineralogy title is chromite.At present, world's chromite produced quantity is about 2,000 ten thousand t/a, and wherein fine ore (particle diameter is less than 8 mm) accounts for 80%, and the fine ore price of chromite is lower than lump ore, therefore a lot of enterprises of producing stainless steel all wish effectively to utilize the refining of chromite powder mining and metallurgy to produce stainless steel, to reduce production costs.Although the fine ore price of chromite is lower than lump ore, in smelting the ferrochrome process, fine ore too much can make the furnace charge air permeability variation, and the working of a furnace worsens, and has a strong impact on every technico-economical comparison, causes yield rate to reduce, and its loss that causes is larger.Therefore, utilizing the chromite fine ore of relative low price to carry out sintering for agglumeration, is that reduction chromium is one of effective way of iron alloy production cost, the raising stainless steel production market competitiveness.But because the wettability of chromite is poor, independent chromite powder mine disaster has a negative impact to sintering effect in the granulation balling-up, and the picotite fusing point is higher, chromite just can produce liquid phase when higher temperature, these factors have all increased the technical difficulty of chromite fine ore sintering.At present, chromite fine ore sintering increases amount of liquid phase by adding the flux such as chlorite, quartzite, serpentine, magnesia and corresponding raising mixed carbon comtent usually, promotes sintering effect; But this mode carbon consumption is larger, and energy consumption is higher, and the flux that adds causes the slag kind of follow-up stainless steel smelting operation and quantity discharged to increase, and this is just so that enterprises of producing stainless steel faces huge energy-saving and emission-reduction pressure; Simultaneously, although the fine ore price of chromite is relatively low, but chromite fine ore sintering extra flux and the mixed carbon comtent cost that increases, so that the advantage of chromite fine ore raw materials cost is difficult to significantly be embodied, be difficult to reach the purpose of effective lifting market competitiveness in stainless steel production holistic cost.

Summary of the invention

For above shortcomings in the prior art, the object of the present invention is to provide a kind of chromite fine ore sintering processing method for stainless steel production, promote chromite fine ore sintering effect, reduce consumption charcoal amount, reduce energy consumption, high with chromite fine ore sintering energy consumption in the solution prior art, as to be unfavorable for energy-saving and emission-reduction problem.

For achieving the above object, the present invention has adopted following technique means:

A kind of chromite fine ore sintering processing method for stainless steel production comprises the steps:

The compound adding drum mixer of 1) 18 ~ 40.5 weight part laterites, 38.5 ~ 54 weight part chromite fine ores, 4 ~ 8 weight part coke powders and 10 ~ 20 weight parts being returned mine form, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Described returning mine is after the resulting agglomerate of chromite sintering sieves before this, with particle diameter less than the agglomerate of 5mm as returning mine;

2) laying depth is the grate-layer material of 20 ~ 25mm on sintering pallet; Described grate-layer material is after the resulting agglomerate of chromite sintering sieves before this, is that agglomerate between 10 ~ 25mm is as grate-layer material with particle diameter;

3) adopting distributor that described mixing pellet evenly is laid in the grate-layer material on the sintering pallet, is that 1000 ℃ ~ 1100 ℃, 1.5 ~ 2 minutes ignition time, exhausting pressure are to carry out sintering under the condition of negative pressure 8 ~ 10kpa in ignition temperature, obtains agglomerate;

4) agglomerate that back is obtained carries out hot break process, so that the agglomerate particle diameter is less than or equal to 40mm after broken; Then be cooled to room temperature, the recycling vibratory screening apparatus sieves, with particle diameter less than the agglomerate of 5mm as returning mine of chromite sintering after this, getting a part of particle diameter is the after this grate-layer material of chromite sintering of agglomerate conduct of 10 ~ 25mm, and remaining agglomerate is used for follow-up stainless steel production and processing process as the agglomerate product.

As a kind of prioritization scheme, in the described step 1, the ratio that forms compound is preferably 39.5 weight part laterites, 39.5 weight part chromite fine ores, 6 weight part coke powders and 15 weight parts and returns mine.

As a kind of prioritization scheme, in the described step 1, granularity accounts for more than 60% at the laterite particle between 0.7 ~ 10mm in the laterite.

As a kind of prioritization scheme, in the described step 4, after agglomerate carries out hot break process, adopt the sintering pallet exhausting to be cooled to room temperature.

Than prior art, the present invention has following beneficial effect:

1, the present invention is used for the chromite fine ore sintering processing method that stainless steel is produced; be used for chromite fine ore sintering processes by adding laterite; because the wettability of laterite and water is good; in pelletization; laterite just can be used as forming core particle and chromite fine ore and mutually adheres to and grow up, and it is agglomerating to granulate, thereby solves the chromite powder mine disaster in the problem of granulating; granulate mixing pellet can be so that the ventilation property of sintering be better, thereby can help to reduce sintering energy consumption and obtain better sintering effect.

2, the present invention is used for the chromite fine ore sintering processing method that stainless steel is produced, the adding of laterite can reduce the chromite sintering temperature, increase amount of liquid phase, reduce energy consumption, improve agglomerate yield rate and intensity, solved chromite powder mine disaster in the prior art in sintering, mixed carbon comtent is high, energy consumption is high problem.

3, in the inventive method, the metallurgical slag set member of laterite and chromite is close, adopt laterite to carry out the just required nichrome product of stainless steel production of the resulting sintered products of chromite fine ore sintering, therefore can not increase the subsequent smelting deslagging operation that stainless steel is produced, and chromite is smelted SiO in the slag system ₂, the low Al of MgO content ₂O ₃Content is high, and laterite is smelted SiO in the slag system ₂, the high Al of MgO content ₂O ₃Content is low, in follow-up smelting process, can shorten the adjustment smelting cycle of slag system, help to reduce the smelting production cost, and the flux of the required costliness of chromite fine ore sintering in the prior art, the relative low price of laterite, therefore chromite and red soil nickel ore mixed sintering effectively reduce the overall cost of stainless steel production cost, have not only improved the economic benefit of enterprise but also alleviated the energy-saving and emission-reduction pressure that enterprise faces.

4, the present invention is based on the required sintering process maturation of chromite fine ore sintering processing method that the nickel-iron smelting slag reclaims, and its treating processes need not to increase new installation.

Description of drawings

Fig. 1 is the schema that the present invention is used for the chromite fine ore sintering processing method of stainless steel production.

Embodiment

High for chromite fine ore sintering energy consumption in the prior art, as to be unfavorable for energy-saving and emission-reduction problem the invention provides a kind of chromite fine ore sintering processing method for stainless steel production, and as shown in Figure 1, the method comprises the steps:

The compound adding drum mixer of 1) 18 ~ 40.5 weight part laterites, 38.5 ~ 54 weight part chromite fine ores, 4 ~ 8 weight part coke powders and 10 ~ 20 weight parts being returned mine form, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Described returning mine is after the resulting agglomerate of chromite sintering sieves before this, with particle diameter less than the agglomerate of 5mm as returning mine;

2) laying depth is the grate-layer material of 20 ~ 25mm on sintering pallet; Described grate-layer material is after the resulting agglomerate of chromite sintering sieves before this, is that agglomerate between 10 ~ 25mm is as grate-layer material with particle diameter;

3) adopting distributor that described mixing pellet evenly is laid in the grate-layer material on the sintering pallet, is that 1000 ℃ ~ 1100 ℃, 1.5 ~ 2 minutes ignition time, exhausting pressure are to carry out sintering under the condition of negative pressure 8 ~ 10kpa in ignition temperature, obtains agglomerate;

4) agglomerate that back is obtained carries out hot break process, so that the agglomerate particle diameter is less than or equal to 40mm after broken; Then be cooled to room temperature, the recycling vibratory screening apparatus sieves, with particle diameter less than the agglomerate of 5mm as returning mine of chromite sintering after this, getting a part of particle diameter is the after this grate-layer material of chromite sintering of agglomerate conduct of 10 ~ 25mm, and remaining agglomerate is used for follow-up stainless steel production and processing process as the agglomerate product.

In granulation, affect sintering effect for the chromite powder mine disaster, and its main component is chromohercynite (FeCr ₂O ₄), chromium sesquioxide (Cr ₂O ₃) problem such as fusing point is high, and the sintering difficulty is large, the present invention has adopted special sintering process, adds granulation and sintering that laterite participates in the chromite fine ore; Laterite is a kind of Raw Ore of enterprises of producing stainless steel long purchase, produce required Rhometal in order to smelting stainless steel processed, for enterprises of producing stainless steel, be easy to obtain, and because the wettability of laterite and water is good, in pelletization, laterite just can be used as forming core particle and chromite fine ore and mutually adheres to and grow up, it is agglomerating to granulate, thereby solve the chromite powder mine disaster in the problem of granulating, the acquisition of granulating mixes pellet can be so that the ventilation property of sintering be better, thereby can help to reduce sintering energy consumption and obtain better sintering effect, here, in order to guarantee better granulating efficiency, guarantee that preferably granularity accounts for more than 60% at the laterite particle between 0.7 ~ 10mm in the laterite; On the other hand, in sintering process, the main component chromohercynite (FeCr of chromite fine ore ₂O ₄), chromium sesquioxide (Cr ₂O ₃), aluminum oxide (Al ₂O ₃) fusing point higher (1450 ℃～1500 ℃), the silicon-dioxide (SiO that fusing point is lower ₂), the content of magnesium oxide (MgO) is less, and the liquid phase that the chromite fine ore self produces in the sintering process is mainly silicate, so the amount of liquid phase that himself produces is less, and silicon-dioxide (SiO in the laterite ₂), magnesium oxide (MgO) content is higher, can produce more liquid phases under low mixed carbon comtent condition, thereby help to improve sintering quality, reduction sintering energy consumption, solved chromite powder mine disaster in the prior art in sintering, mixed carbon comtent height, problem that energy consumption is high; In addition, the metallurgical slag set member of laterite and chromite is close, adopt laterite to carry out the just required nichrome product of stainless steel production of the resulting sintered products of chromite fine ore sintering, therefore can not increase the subsequent smelting deslagging operation that stainless steel is produced, and chromite is smelted SiO in the slag system ₂, the low Al of MgO content ₂O ₃Content is high, and laterite is smelted SiO in the slag system ₂, the high Al of MgO content ₂O ₃Content is low, in follow-up smelting process, can shorten the adjustment smelting cycle of slag system, help to reduce the smelting production cost, and the flux of the required costliness of chromite fine ore sintering in the prior art, the relative low price of laterite, the more important thing is that red soil nickel ore is the main raw material of producing ferronickel, nickel and chromium are the basic interpolation elements of austenitic stainless steel simultaneously, interpolation laterite sintering has not only solved the problem of chromite sintering aspect, in the subsequent smelting process, can produce simultaneously alloy simultaneously nickeliferous and chromium, can not produce the stainless essential elemental nickel of adding and add other flux, therefore chromite and red soil nickel ore mixed sintering effectively reduce the stainless steel production cost, the fine ore of chromite is more cheap than lump ore in addition, thereby has reduced the overall cost that stainless steel is produced.In addition in the sintering method of the present invention, the agglomerate that also sintering processes is obtained carries out hot break process and is cooled to after the room temperature few minute and is returned mine and grate-layer material, its cooling process adopts the cooling of sintering pallet exhausting, so namely can promote cooling process efficient and need not again to increase other cooling apparatus, save cost, and require the agglomerate particle diameter to be less than or equal to 40mm after the fragmentation, make it meet follow-up stainless steel process for processing (for example electric furnace processing) process to the requirement of raw material granularity; Wherein, particle diameter less than the agglomerate of 5mm as returning mine of chromite sintering after this, particle diameter is that the agglomerate of 5mm ~ 40mm can be used as the agglomerate product, because particle diameter is too small and be unfavorable for follow-up stainless steel production less than the particle diameter of returning mine of 5mm, but its chromium grade is higher, and the surface irregularity of returning mine, and can be used as capable nuclear particle and chromite fine ore and mutually adheres to and grow up, be conducive to granulate, therefore namely can reclaim the chromium element, can be used as capable nuclear particle again and help mixing granulation as this chromite sintering; And in the agglomerate product, can get again a part of particle diameter is the after this grate-layer material of chromite sintering of agglomerate conduct of 10 ~ 25mm, the laying depth of grate-layer material is 20 ~ 25mm, the ratio that burns out in order to reduce grid section, guarantee exhausting amount and ventilation effect, avoid sintered material to be bonded at and reduce the exhausting area on the grate bar, stop that fine particle enters bellows with waste gas and shortens the vacuum fan life-span.

This shows, chromite fine ore sintering processing method of the present invention has promoted chromite fine ore sintering effect, reduced consumption charcoal amount, reduced energy consumption, the sintered products that obtains is the nichrome product, can be directly used in stainless steel production, can not increase the subsequent smelting deslagging operation that stainless steel is produced, thereby help the enterprises of producing stainless steel energy-saving and emission-reduction; And when having reduced mixed carbon comtent, need not the flux by costliness in the chromite fine ore sintering processing method of the present invention, thereby help to reduce the overall cost that stainless steel is produced, not only improved the economic benefit of enterprise but also alleviated the energy-saving and emission-reduction pressure that enterprise faces.

Below in conjunction with embodiment technical scheme of the present invention is further described.

Embodiment:

Present embodiment adopts the inventive method to carry out three groups of chromite fine ore sintering experiments, also adopt in addition the method for adding flux in the prior art to carry out two groups of chromite fine ore sintering experiments, then the physical index of chromite fine ore sintering experiment gained agglomerate product is respectively organized in contrast.The coke powder Chemical Composition that adopts in the present embodiment sees Table 1, and other material chemical components see Table 2:

Table 1 coke powder Chemical Composition

Table 2 raw material chemistry part

Carry out 5 groups of chromite fine ore sintering experiments in the present embodiment, be numbered respectively 1# group, 2# group, 3# group, 4# group, 5# group, 6# group, 7# group, 8# group; Wherein 1# ~ 6# group chromite fine ore sintering experiment adopts chromite fine ore sintering processing method of the present invention to carry out sintering processes, and the sintering temperature during sintering processes, pressure, sintering time are all in the claimed range of chromite fine ore sintering processing method of the present invention; 7# group chromite fine ore sintering experiment has adopted the chromite sinter mixture proportioning of commonly using in the prior art, utilize chlorite as flux, and added wilkinite and be beneficial to pelletizing and granulate, correspondingly added simultaneously the proportioning weight part of coke powder to increase mixed carbon comtent, guarantee sintering effect, then testing under the identical sintering condition with 1 ~ 6# group, adopting identical treatment scheme to carry out sintering processes; 8# group chromite fine ore sintering experiment has adopted the chromite sinter mixture proportioning of commonly using in the prior art equally, utilize Turkey's concentrate as flux, also add wilkinite and be used for the pelletizing granulation, correspondingly added simultaneously the proportioning weight part of coke powder to increase mixed carbon comtent, then tested under the identical sintering condition with 1 ~ 6# group, adopting identical treatment scheme to carry out sintering processes.Adopting the same terms to carry out sintering processes is for the ease of contrasting the sintering effect of 5 groups of chromite fine ore sintering experiments, and the mix material proportioning of 8 groups of chromite fine ore sintering experiments is as shown in table 3.

Table 3

After finishing the sintering processes of above-mentioned 8 groups of chromite fine ore sintering experiments, respectively yield rate, dropping strength, barrate strength and four physicalies of wear-resistant index of the agglomerate product of 8 groups of chromite fine ore sintering experiment gained are detected, and calculate the agglomerate consumption charcoal amount per ton of respectively organizing chromite fine ore sintering reality, resulting detected result is as shown in table 4.

Table 4

Can find out from above-mentioned data, the 1# of employing the inventive method ~ 6# group chromite fine ore sintering experiment, the property indices of agglomerate product is the rear variation that improves first along with coke distribution amount is increased to 8% variation tendency from 4%, when joining Jiao and being 6%, it is best that agglomerate detects index, therefore think in this kind batching situation, best with addition of 6% coke powder sintering effect.This mainly is because in the sintering process, the removing so that hole appears in sinter bed of laterite crystal water and hydroxyl, and it is fabulous that bed permeability becomes, the coke powder sufficient combustion, therefore when coke powder was reduced to 6%, the energy that provides was enough.And adopt in the chromite fine ore sintering experiment of 6% coke distribution amount these two groups of 2# and 4#, four physicalies of 2# group chromite fine ore sintering experiment are more excellent, therefore organize chromite fine ore sintering experiment as the reference foundation with 2#, in the methods of the invention, the ratio that forms compound is preferably 39.5 weight part laterites, 39.5 weight part chromite fine ores, 6 weight part coke powders and 15 weight parts and returns mine.

7# group chromite fine ore sintering experiment is to adopt chromite sintering process commonly used in the prior art, adds chlorite shaping nuclear particle and adds the wilkinite that improves mineral and wettability, is conducive to balling-up for improving granulation and sintering effect.For the 2# group chromite fine ore sintering experiment of the embodiment of the invention, its burnt amount increases by 4%, adds flux chlorite 15%, wilkinite 6%, and the sintering cost improves and the every physical index of agglomerate descends to some extent.8# group chromite fine ore sintering experiment reduces the interpolation of flux but coke powder is very high with addition of amount, and the relative novel process embodiment 2# of the every physical index of agglomerate declines to a great extent.

Therefore, with respect to present chromite sintering process, mixed sintering novel process coke distribution amount of the present invention is few, need not solvent and wilkinite and adds, and energy consumption reduces, and sinter quality improves, and resource utilization improves, and can effectively reduce enterprise cost and improve economic benefit.

Explanation is at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although with reference to preferred embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from aim and the scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (4)

1. one kind is used for the chromite fine ore sintering processing method that stainless steel is produced, and it is characterized in that, comprises the steps:

The compound adding drum mixer of 1) 18 ~ 40.5 weight part laterites, 38.5 ~ 54 weight part chromite fine ores, 4 ~ 8 weight part coke powders and 10 ~ 20 weight parts being returned mine form, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Described returning mine is after the resulting agglomerate of chromite sintering sieves before this, with particle diameter less than the agglomerate of 5mm as returning mine;

2) laying depth is the grate-layer material of 20 ~ 25mm on sintering pallet; Described grate-layer material is after the resulting agglomerate of chromite sintering sieves before this, is that agglomerate between 10 ~ 25mm is as grate-layer material with particle diameter;

3) adopting distributor that described mixing pellet evenly is laid in the grate-layer material on the sintering pallet, is that 1000 ℃ ~ 1100 ℃, 1.5 ~ 2 minutes ignition time, exhausting pressure are to carry out sintering under the condition of negative pressure 8 ~ 10kpa in ignition temperature, obtains agglomerate;

4) agglomerate that back is obtained carries out hot break process, so that the agglomerate particle diameter is less than or equal to 40mm after broken; Then be cooled to room temperature, the recycling vibratory screening apparatus sieves, with particle diameter less than the agglomerate of 5mm as returning mine of chromite sintering after this, getting a part of particle diameter is the after this grate-layer material of chromite sintering of agglomerate conduct of 10 ~ 25mm, and remaining agglomerate is used for follow-up stainless steel production and processing process as the agglomerate product.

2. the chromite fine ore sintering processing method of producing for stainless steel according to claim 1, it is characterized in that, in the described step 1, the ratio that forms compound is preferably 35.5 weight part laterites, 39.5 weight part chromite fine ores, 6 weight part coke powders and 20 weight parts and returns mine.

3. the chromite fine ore sintering processing method for stainless steel production according to claim 1 is characterized in that in the described step 1, granularity accounts for more than 60% at the laterite particle between 0.7 ~ 10mm in the laterite.

4. the chromite fine ore sintering processing method for stainless steel production according to claim 1 is characterized in that, in the described step 4, after agglomerate carries out hot break process, adopts the sintering pallet exhausting to be cooled to room temperature.