CN103045859B - A kind of chromite fine ore sintering processing method produced for stainless steel - Google Patents

Abstract

The invention provides a kind of chromite fine ore sintering processing method produced for stainless steel, chromite powder is mainly carried out granulation sintering by the method after laterite, because the wettability of laterite and water is good, in pelletization, laterite just can adhere to as forming core particle and chromite fine ore mutually grows up, granulate agglomerating, thus solve chromite powder mine disaster in the problem of granulating, chromite sintering temperature can be reduced adding of laterite simultaneously, increase amount of liquid phase, reduce energy consumption, improve agglomerate yield rate and intensity, to solve in prior art chromite powder mine disaster in sintering, mixed carbon comtent is high, the problem that energy consumption is high, and the metallurgical slag set member of laterite and chromite is close, the subsequent smelting deslagging operation that stainless steel is produced can not be increased, and relative low price, effectively can reduce the overall cost of stainless steel production cost, not only improve the economic benefit of enterprise but also alleviated the energy-saving and emission-reduction pressure that enterprise faces.

Description

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

Technical field

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

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 used in the world about has 65% ~ 70% to be austenitic stainless steel.Chromium nickel system stainless steel accounts for 2/3rds of world's stainless steel output.For ensureing stainless steel institute intrinsic corrosiom resistance, steel must contain the nickel content of chromium more than 16%, more than 8%.Chromium and nickel produce stainless basic Addition ofelements.China needs to produce a large amount of ferrochrome and ferronickel every year.Due to China's chrome ore reserves only 0.15%, be the poor country of a chromium, need a large amount of import chrome ore therefore every year, external dependence degree reaches more than 95%.

Chromium always forms chromohercynite (FeO.Cr with iron symbiosis at occurring in nature ₂o ₃), its mineralogical name 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 wishes that can effectively utilize chromite powder mining and metallurgy to refine produces stainless steel, to reduce production cost.Although the fine ore price of chromite is lower than lump ore, in smelting ferrochrome process, fine ore too much can make furnace charge air permeability be deteriorated, and the working of a furnace worsens, and have a strong impact on every technico-economical comparison, cause yield rate to reduce, its loss caused is larger.Therefore, utilizing the chromite fine ore of relative low price to carry out sintering for agglumeration, is one of effective way reducing chromium system J. sigillate cost, improve the stainless steel production market competitiveness.But because the wettability of chromite is poor, independent chromite powder mine disaster, in granulation balling-up, has a negative impact to sintering effect, and picotite fusing point is higher, chromite just can produce liquid phase when higher temperature, and these factors both increase the technical difficulty of chromite powder mine sintering.At present, chromite powder mine sintering by adding the flux such as chlorite, quartzite, serpentine, magnesia and corresponding raising mixed carbon comtent increases amount of liquid phase, promotes sintering effect usually; But this mode carbon consumption is comparatively large, and energy consumption is higher, and the flux added causes the slag kind of follow-up stainless steel smelting operation and quantity discharged to increase, and this just makes enterprises of producing stainless steel face huge energy-saving and emission-reduction pressure; Simultaneously, although the fine ore price of chromite is relatively low, but the flux that chromite powder mine sintering additionally increases and mixed carbon comtent cost, make the advantage of chromite fine ore raw materials cost be difficult to produce in holistic cost at stainless steel significantly embodied, be difficult to reach the object effectively promoting the market competitiveness.

Summary of the invention

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

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

For the chromite fine ore sintering processing method that stainless steel is produced, comprise the steps:

1) compound formed of 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 adds drum mixer, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Describedly to return mine, being that chromite sinters after the agglomerate obtained sieves before this, particle diameter being less than the agglomerate of 5mm as returning mine;

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

3) adopt distributor to be evenly laid in the grate-layer material on sintering pallet by described mixing pellet, ignition temperature be 1000 DEG C ~ 1100 DEG C, 1.5 ~ 2 minutes ignition time, exhausting pressure sinters under being the condition of negative pressure 8 ~ 10kpa, obtains agglomerate;

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

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

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

Compared to 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; chromite fine ore sintering processes is used for by adding laterite; because the wettability of laterite and water is good; in pelletization; laterite just can adhere to as forming core particle and chromite fine ore mutually grows up, and granulates agglomerating, thus solves chromite powder mine disaster in the problem of granulating; the ventilation property that acquisition mixing pellet of granulating can make to sinter is better, thus can help reduce sintering energy consumption and obtain better sintering effect.

2, the present invention is used in the chromite fine ore sintering processing method of stainless steel production, adding of laterite can reduce chromite sintering temperature, increase amount of liquid phase, reduce energy consumption, improve agglomerate yield rate and intensity, solve chromite powder mine disaster in 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, employing laterite carries out the nichrome product of sintered products just needed for stainless steel production that chromite powder mine sintering obtains, therefore can not increase the subsequent smelting deslagging operation that stainless steel is produced, and chromite smelts SiO in slag system ₂, the low Al of content of MgO ₂o ₃content is high, and laterite smelts SiO in slag system ₂, content of MgO height Al ₂o ₃content is low, the adjustment smelting cycle of slag system can be shortened in follow-up smelting process, help to reduce and smelt production cost, and compared to the flux of the costliness in prior art needed for chromite powder mine sintering, 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 improve the economic benefit of enterprise but also have alleviated the energy-saving and emission-reduction pressure that enterprise faces.

4, the present invention is based on the maturation of the sintering process needed for chromite fine ore sintering processing method that nickel-iron smelting slag reclaims, and its treating processes is without the need to increasing new installation.

Accompanying drawing explanation

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

Embodiment

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

1) compound formed of 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 adds drum mixer, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Describedly to return mine, being that chromite sinters after the agglomerate obtained sieves before this, particle diameter being less than the agglomerate of 5mm as returning mine;

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

3) adopt distributor to be evenly laid in the grate-layer material on sintering pallet by described mixing pellet, ignition temperature be 1000 DEG C ~ 1100 DEG C, 1.5 ~ 2 minutes ignition time, exhausting pressure sinters under being the condition of negative pressure 8 ~ 10kpa, obtains agglomerate;

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

For chromite powder mine disaster in granulation, affect sintering effect, and its main component is chromohercynite (FeCr ₂o ₄), chromium sesquioxide (Cr ₂o ₃) problem such as fusing point is high, and sintering difficulty is large, present invention employs special sintering process, add granulation and sintering that laterite participates in chromite fine ore, laterite is a kind of Raw Ore of enterprises of producing stainless steel long purchase, Rhometal needed for producing in order to smelting stainless steel, be easy to obtain for enterprises of producing stainless steel, and due to the wettability of laterite and water good, in pelletization, laterite just can adhere to as forming core particle and chromite fine ore mutually grows up, granulate agglomerating, thus solve chromite powder mine disaster in the problem of granulating, the ventilation property that acquisition mixing pellet of granulating can make to sinter is better, thus can help reduce sintering energy consumption and obtain better sintering effect, here, in order to ensure better granulating efficiency, preferably guarantee that in laterite, the laterite particle of granularity between 0.7 ~ 10mm accounts for more than 60%, 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 DEG C ~ 1500 DEG C), the silicon-dioxide (SiO that fusing point is lower ₂), the content of magnesium oxide (MgO) is less, and the liquid phase that in sintering process, chromite fine ore self produces is mainly silicate, and the amount of liquid phase therefore himself produced is less, and silicon-dioxide (SiO in laterite ₂), magnesium oxide (MgO) content is higher, can produce more liquid phases under lower mixed carbon comtent condition, thus helps to improve sintering quality, reduce sintering energy consumption, solves chromite powder mine disaster in prior art in sintering, mixed carbon comtent is high, energy consumption is high problem, in addition, the metallurgical slag set member of laterite and chromite is close, employing laterite carries out the nichrome product of sintered products just needed for stainless steel production that chromite powder mine sintering obtains, therefore can not increase the subsequent smelting deslagging operation that stainless steel is produced, and chromite smelts SiO in slag system ₂, the low Al of content of MgO ₂o ₃content is high, and laterite smelts SiO in slag system ₂, content of MgO height Al ₂o ₃content is low, the adjustment smelting cycle of slag system can be shortened in follow-up smelting process, help to reduce and smelt production cost, and compared to the flux of the costliness in prior art needed for chromite powder mine sintering, the relative low price of laterite, the more important thing is that red soil nickel ore is the main raw material producing ferronickel, nickel and chromium are the basic Addition ofelements of austenitic stainless steel simultaneously, add the problem that laterite sintering not only solves chromite sintering aspect, the alloy of nickeliferous and chromium simultaneously can be produced in subsequent smelting process simultaneously, and add other flux and can not produce stainless required Addition ofelements nickel, therefore chromite and red soil nickel ore mixed sintering effectively reduce stainless steel production cost, in addition the fine ore of chromite is more cheap than lump ore, thus reduce the overall cost of stainless steel production.In addition in sintering method of the present invention, the agglomerate also sintering processes obtained carries out dividing less after hot break process is cooled to room temperature being returned mine and grate-layer material, its cooling process adopts the cooling of sintering pallet exhausting, so not only, cooling process efficiency can be promoted but also without the need to increasing other cooling apparatus, save cost, and after fragmentation, require that agglomerate particle diameter is less than or equal to 40mm, make it meet follow-up stainless steel process for processing (such as electric furnace processing) process to the requirement of raw material granularity; Wherein, the agglomerate that particle diameter is less than 5mm is returned mine as after this chromite sintering, particle diameter is that the agglomerate of 5mm ~ 40mm can as agglomerate product, because it is too small and be unfavorable for that follow-up stainless steel is produced that particle diameter is less than the particle diameter of returning mine of 5mm, but its chromium grade is higher, and surface irregularity of returning mine, can be used as row nuclear particle and chromite fine ore and mutually adhere to and grow up, not only be conducive to granulating, be therefore used as this chromite sintering and can reclaim chromium element, but also mixing granulation can be helped as row nuclear particle; And in agglomerate product, the grate-layer material of agglomerate as after this chromite sintering that a part of particle diameter is 10 ~ 25mm can be got again, the laying depth of grate-layer material is 20 ~ 25mm, in order to reduce the ratio that grid section burns out, ensure exhausting amount and ventilation effect, avoid sintered material to be bonded on grate bar and reduce exhausting area, stop that fine particle enters bellows with waste gas and shortens the vacuum fan life-span.

As can be seen here, chromite fine ore sintering processing method of the present invention improves chromite fine ore sintering effect, decrease consumption charcoal amount, reduce energy consumption, the sintered products obtained is nichrome product, stainless steel can be directly used in produce, the subsequent smelting deslagging operation that stainless steel is produced can not be increased, thus contribute to enterprises of producing stainless steel energy-saving and emission-reduction; And in chromite fine ore sintering processing method of the present invention while decreasing mixed carbon comtent without the need to the flux by costliness, thus contribute to reducing the overall cost that stainless steel produces, not only improve 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:

The present embodiment adopts the inventive method to carry out three groups of chromite fine ore sintering experiments, also adopt the method for adding flux in prior art to carry out two groups of chromite fine ore sintering experiments in addition, then contrast the physical index of each group of chromite fine ore sintering experiment gained agglomerate product.The coke powder Chemical Composition adopted in the present embodiment is in table 1, and other material chemical components are in 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 1# group, 2# group, 3# group, 4# group, 5# group, 6# group, 7# group, 8# group respectively; 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 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 have employed chromite sinter mixture proportioning conventional in prior art, utilize chlorite as flux, and with the addition of wilkinite be beneficial to pelletizing granulate, correspondingly with the addition of the proportioning weight part of coke powder to increase mixed carbon comtent simultaneously, ensure sintering effect, then testing under identical sintering condition with 1 ~ 6# group, adopting identical treatment scheme to carry out sintering processes; 8# group chromite fine ore sintering experiment have employed chromite sinter mixture proportioning conventional in prior art equally, utilize Turkey's concentrate as flux, also with the addition of wilkinite to granulate for pelletizing, correspondingly with the addition of the proportioning weight part of coke powder to increase mixed carbon comtent simultaneously, then testing under 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 sintering effect for the ease of contrasting 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 completing the sintering processes of above-mentioned 8 groups of chromite fine ore sintering experiments, respectively the yield rate of the agglomerate product of 8 groups of chromite fine ore sintering experiment gained, dropping strength, barrate strength and anti-wear index four physicalies are detected, and calculating the agglomerate consumption charcoal amount per ton of each group of chromite powder mine sintering reality, the detected result obtained is as shown in table 4.

Table 4

As can be seen from above-mentioned data, adopt 1# ~ 6# group chromite fine ore sintering experiment of the inventive method, the property indices of agglomerate product is deteriorated from the variation tendency that 4% is increased to 8% for first improving afterwards along with coke distribution amount, when to join Jiao be 6%, agglomerate Testing index is best, therefore think in this kind of batching situation, best with addition of 6% coke powder sintering effect.This is mainly due in sintering process, and laterite crystal water and removing of hydroxyl make sinter bed occur hole, and bed permeability becomes fabulous, coke powder sufficient combustion, and therefore when coke powder is reduced to 6%, the energy provided is enough.And adopt in the chromite fine ore sintering experiment of 6% coke distribution amount 2# and 4# these two groups, four physicalies of 2# group chromite fine ore sintering experiment are more excellent, therefore using 2# group chromite fine ore sintering experiment as reference foundation, in the methods of the invention, the ratio forming 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 adopts chromite sintering process conventional in prior art, to granulate and sintering effect adds chlorite shaping nuclear particle and interpolation improves mineral and wettability, is conducive to the wilkinite of balling-up for improving.For the 2# group chromite fine ore sintering experiment of the embodiment of the present invention, its burnt amount increase by 4%, adds flux chlorite 15%, wilkinite 6%, and sintering cost improves and the every physical index of agglomerate declines 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, relative to current chromite sintering process, mixed sintering novel process coke distribution amount of the present invention is few, and add without the need to solvent and wilkinite, energy consumption reduces, and sinter quality improves, and resource utilization improves, and can effectively reduce enterprise cost and improve economic benefit.

What finally illustrate is, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, 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 aim and the scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.

Claims (2)

1., for the chromite fine ore sintering processing method that stainless steel is produced, it is characterized in that, comprise the steps:

1) compound formed of 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 adds drum mixer, add water by 10% of described compound gross weight again and carry out mixing granulation, obtain mixing pellet; Describedly to return mine, being that chromite sinters after the agglomerate obtained sieves before this, particle diameter being less than the agglomerate of 5mm as returning mine; In described laterite, the laterite particle of granularity between 0.7 ~ 10mm accounts for more than 60%;

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

3) adopt distributor to be evenly laid in the grate-layer material on sintering pallet by described mixing pellet, ignition temperature be 1000 DEG C ~ 1100 DEG C, 1.5 ~ 2 minutes ignition time, exhausting pressure sinters under being the condition of negative pressure 8 ~ 10kPa, obtains agglomerate; Adding of laterite can reduce chromite sintering temperature, increases amount of liquid phase;

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

2. the chromite fine ore sintering processing method produced for stainless steel according to claim 1, it is characterized in that, in described step 1, the ratio of composition 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.