CN102925601A - Method for evaluating high-temperature softening-melting dropping properties of iron-bearing burden - Google Patents

Abstract

The invention relates to a method for evaluating high-temperature softening-melting dropping properties of iron-bearing burden and provides a novel evaluation way for high-temperature softening-melting dropping properties of the iron-bearing burden. The evaluation comprises evaluation of lump ore, pellet, sintering ore, comprehensive burden and metalized iron-bearing burden. The method comprises division of iron-bearing burden softening-melting dropping temperature regions, a calculation method of property characteristic value in the regions, and evaluation of iron-bearing burden softening-melting dropping properties, and provides technical guide and support for evaluating the high-temperature softening-melting dropping properties of the iron-bearing burden. By the method, the size of the iron-bearing burden regions, and the pressure difference and shrinkage rate of material columns can be intuitively reflected, evaluation on the softening-melting dropping properties of the novel blast furnace burden and the influence of the softening-melting dropping properties on a softening-melting zone is facilitated, and significance for guiding the regulation of the upper part of the blast furnace is made.

Description

A kind of evaluation method of iron-containing charge high temperature soft melting dropping characteristic

Technical field

The present invention relates to a kind of evaluation of iron-containing charge high temperature soft melting dropping characteristic, comprise the evaluation of lump ore, pellet, agglomerate, comprehensive furnace charge and metallization iron-containing charge.

Background technology

Adopt search condition: summary=(iron-containing charge) AND summary=(soft melting dropping characteristic); Or, summary=(iron-containing charge) AND summary=(evaluation); And abstract=(iron-bearingburden) AND abstract=(Softening-melting dropping properties) database is at home and abroad retrieved.Through carefully retrieval, not and originally declare the same or similar summary of the invention of patent.

The soft melting dropping characteristic of iron-containing charge has determined structure, position, the thickness of blast furnace melting with soft, and directly affects the distribution of shaft lump zone Gas Flow and the indirect reduction of iron ore, is determining coke consumption amount and smooth operation of furnace.Therefore, the soft melting dropping characteristic of comprehensive and accurate evaluation iron-containing charge not only helps the ironmaking worker that the blast furnace melting with soft characteristic is carried out correct prediction, also is simultaneously one of basis that guarantees blast furnace high yield, high-quality and low consumption.

The existing evaluation method of iron-containing charge soft melting dropping characteristic is comparatively mixed and disorderly, the evaluation of adopting diverse ways to carry out to same iron-containing charge soft melting dropping characteristic, its result has larger difference, and can not accurate evaluation to some novel furnace charges, causes evaluation result to be difficult to the production of accurate instruction blast furnace.Particularly there is in recent years research to attempt the new technology that blast furnace uses the novel iron-containing furnace charges such as carbon-bearing lump, prereduced burden, scrap metal, because when iron-containing charge is displaced downwardly to cohesive zone, the difference of its degree of metalization, carbon content and the quantity of slag etc. all can cause shape, position, stock column contraction change and the stock column Pressure difference distribution etc. of cohesive zone to present difference, therefore more be necessary its soft melting dropping characteristic is carried out accurate evaluation for the novel iron-containing furnace charge, instruct in order to it is applied to blast furnace production.Yet existing evaluation method can not well be estimated these because of the variation of reducing degree furnace charge soft melting dropping characteristic that variation causes in new raw material, the blast furnace.Therefore, the soft melting dropping characteristic of the various iron-containing charges of the evaluation that how to hold water under new technology and novel process is to realize the key of above new technology.

Domestic existing evaluation method is that the soft melting dropping temperature range with iron-containing charge is divided into the interval and droplet temperature interval of softening temperature, and doing a few thing aspect the parameters such as softening beginning temperature, softening finishing temperature and fusing beginning temperature, but because the smelting associativity of assessment indicator system and blast furnace is relatively poor, the practical situation of blast-furnace smelting of failing deeply to consider are therefore can not more comprehensively embody the structure and characteristics of cohesive zone in the blast furnace ironmaking process.Therefore, the deficiency of domestic existing evaluation method cause the interpretation of iron-containing charge soft melting dropping difficulty be applied to actual blast furnace production.

Mainly be to consider that fusing beginning temperature is to this interval of fusing finishing temperature to the evaluation of iron-containing charge soft melting dropping characteristic abroad, yet fusing beginning temperature also there is different definition with the fusing finishing temperature, carries out melt-dropping property population characteristic value (S) that integration obtains with the interior pressure reduction of this temperature range the hot properties of iron-containing charge is carried out comprehensive evaluation.Iron-containing charge pressure reduction from softening the beginning just begins to increase, and till being continued until that the stock column maximum differential pressure occurs, therefore only the practical situation that are not enough to react iron-containing charge cohesive zone in the blast furnace are estimated in the droplet temperature interval.

Therefore, working out the evaluation method that reasonably also can really react iron-containing charge soft melting dropping characteristic is a problem demanding prompt solution.

Summary of the invention

Purpose of the present invention, it is the new evaluating method that proposes a kind of iron-containing charge soft melting dropping characteristic, comprise the division of iron-containing charge soft melting dropping temperature range, the method of calculation of the performance characteristic value that each is interval and to the evaluation of iron-containing charge soft melting dropping performance can provide technical director and support for the evaluation of iron-containing charge high temperature soft melting dropping characteristic.

Technical scheme of the present invention is as follows:

This evaluation method is with the soft melting dropping temperature range T of iron-containing charge _d-T _sBe divided into soft heat layer, melting layer and drippage layer, the soft heat layer is defined as soft heat and begins temperature to the interval corresponding iron-containing charge layer of soft heat finishing temperature, melting layer is defined as melting and begins temperature to the interval corresponding iron-containing charge layer of melting finishing temperature, and the drippage layer is defined as the melting finishing temperature to the right iron-containing charge layer of molten iron drippage temperature range;

Wherein, soft heat begins temperature T _s: the temperature that pressure reduction obviously raises or the stock column shrinking percentage obviously increases; Soft heat finishing temperature T _m: the temperature that pressure reduction begins to skyrocket; Melting begins temperature T _m: the temperature that pressure reduction begins to skyrocket; Melting finishing temperature Tp _Max: the temperature that maximum differential pressure is corresponding, when the poor peak of maximal pressure that has two pressure reduction to be more or less the same, select from nearest one of molten iron drippage temperature as the poor peak of maximal pressure; Molten iron drippage temperature T _d: the temperature that molten iron begins to drip in the stock column;

According to temperature and the pressure reduction parameter of the correspondence of soft heat layer, melting layer and drippage layer, iron-containing charge soft heat performance characteristic value SMD is proposed ₁, iron-containing charge melting behaviour eigenwert SMD ₂, iron-containing charge melt-dropping property eigenwert SMD ₃And begin to the corresponding soft melting dropping performance eigenwert of molten iron drippage temperature range SMD, according to SMD from the iron-containing charge soft heat ₁, SMD ₂, SMD ₃Judge each interval soft melting dropping performance of iron-containing charge and total soft melting dropping performance with the SMD value; SMD ₁, SMD ₂, SMD ₃Less with SMD, the soft melting dropping performance of iron-containing charge is better; Such as SMD ₁Less, show that the soft heat performance of iron-containing charge is better, otherwise its soft heat performance is poorer; SMD ₂Less, show that the melting behaviour of iron-containing charge is better, otherwise its soft heat performance is poorer; SMD ₃Similar with it;

Its corresponding calculation formula is as follows:

${\mathrm{SMD}}_1={\∫}_{T_s}^{T_m}\mathrm{\ΔP}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_s}{\overset{T_m}{\mathrm{\Σ}}}(\mathrm{\Δ}{P}_{i+1}+\mathrm{\Δ}{P}_i)\×(T_{i+1}+T_i)---\left(1\right)$

Formula (1) expression soft heat performance characteristic value (SDM ₁) end to soft heat for soft heat begins temperature

Pressure reduction is along the integration of temperature, T in the temperature range _iThe expression soft heat begins the arbitrary temp value between temperature and the soft heat finishing temperature, △ P _iPressure difference corresponding to expression temperature T i;

${\mathrm{<figure-callout\; id="2"\; label="SMD"\; filenames="HDA00002299029800011.png"\; state="\{\{state\}\}">SMD</figure-callout>}}_2={\&Integral;}_{T_m}^{T_{P\max }}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_m}{\overset{T_{P\max }}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}+T_i)---\left(2\right)$

Formula (2) expression melting behaviour eigenwert (SDM ₂) end to melting for melting begins temperature

Pressure reduction is along the integration of temperature, T in the temperature range _iThe expression melting begins the arbitrary temp value between temperature and the melting finishing temperature, △ P _iThe expression temperature T _iCorresponding pressure difference;

${\mathrm{SMD}}_3={\&Integral;}_{T_{P\max }}^{T_d}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_{P\max }}{\overset{T_d}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}+T_i)---\left(3\right)$

Formula (3) expression dropping performance eigenwert (SDM ₃) drip for the melting finishing temperature arrives molten iron

Pressure reduction is along the integration of temperature, T in the temperature range _iArbitrary temp value between expression melting finishing temperature and the molten iron drippage temperature, △ P _iThe expression temperature T _iCorresponding pressure difference;

$\mathrm{SMD}={\&Integral;}_{T_s}^{T_d}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}{=\mathrm{SMD}}_1+{\mathrm{SMD}}_2+{\mathrm{SMD}}_3=\frac{1}{2}\underset{i=T_s}{\overset{T_d}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}-T_i)---\left(4\right)$

Formula (4) expression soft melting dropping performance eigenwert (SDM) for begin from soft heat temperature in the drippage temperature range pressure reduction along the integration of temperature, T _iThe expression soft heat begins the arbitrary temp value between temperature and the drippage temperature, △ P _iThe expression temperature T _iCorresponding pressure difference.

Beneficial effect of the present invention is:

The proposition of this evaluation method can be according to cohesive zone performance in the soft melting dropping characteristic parameter reaction blast furnace of iron-containing charge, in order to can better optimize the burden structure of blast furnace, the pressure reduction that improves blast furnace melting with soft, the high yield to guarantee blast-furnace smelting, low consumption and direct motion.

Blast furnace melting with soft is that iron-containing charge forms through softening-melting process, melting process and drippage process.The soft melting dropping process of iron-containing charge is for to begin to soft heat to finish from soft heat, begin to finish to melting through melting again, then the viscosity by slag iron layer determines to continue the not time of drippage after melting finishes, and viscosity is higher, the time that maximum differential pressure continues is longer, and the droplet temperature interval is wider.Therefore, the soft melting dropping process of iron-containing charge being divided into Three regions more matches with actual blast-furnace smelting.

The new evaluating method has solved the interval and molten temperature region of softening temperature in traditional evaluation method and empty temperature range or the problem of overlapping temperature range have always occurred, the soft melting dropping performance eigenwert of calculating iron-containing charge that can be more accurate and its soft melting dropping characteristic of evaluation.

This evaluation method can intuitively embody interval size, stock column pressure reduction and the stock column shrinking percentage in each interval of iron-containing charge, not only help to estimate the melt-dropping property of the novel furnace charge of blast furnace and on the impact of blast furnace melting with soft, and upper blast furnace adjusted have directive significance.

Description of drawings

Accompanying drawing 1: stock column pressure reduction, stock column height vary with temperature figure in the comprehensive furnace charge soft melting dropping process.

Accompanying drawing 2: unit stock column pressure reduction, stock column shrinking percentage vary with temperature figure in the comprehensive furnace charge soft melting dropping process.

Embodiment

Iron-containing charge, coke are respectively the 20g coke by stock column bottom and top layer, and the middle layer is the distributing mode of the iron-containing charge graphite reaction tubes of packing into, and the loading of stock column is 1kg/cm ², begin the molten drop test by the condition of table 1, when molten iron drops to the crucible of alundum tube bottom, close power supply and be cooled to room temperature, off-test.The temperature of process of the test, stock column height and stock column pressure reduction are by computer Real-Time Monitoring record.

The molten drop test conditions of table 1 iron-containing charge

The evaluation contrast of the comprehensive furnace charge soft melting dropping characteristic of table 2 typical case

The used comprehensive furnace charge of certain steel mill's situ production is carried out the soft melting dropping experiment, and stock column pressure reduction, stock column height variation with temperature are as shown in Figure 1 in the soft melting dropping process.The new evaluating method that proposes by existing optimum evaluation method and the application is respectively estimated, and its evaluation result is listed in table 2.By accompanying drawing 2 as can be known, existing optimum evaluation method only can be estimated the softening temperature interval of comprehensive furnace charge and the shrinking percentage of interval corresponding stock column, yet from accompanying drawing 2, can find out, pressure reduction flex point or stock column displacement inflexion do not appear when stock column shrinks 40%, this moment, comprehensive furnace charge was in softening and the melting process, softening end, obviously, existing evaluation method is further improved.Adopt new evaluation method can estimate simultaneously the reflowing temperature interval of comprehensive furnace charge, shrinking percentage, pressure differential range and the unit stock column pressure differential range of interval corresponding stock column.In addition, from the soft heat finishing temperature, no matter be to observe on stock column total pressure head curve or the unit stock column differential pressure curve, this point all is in the starting point that stock column pressure reduction sharply skyrockets, and the obviously flex point of increase appears in the stock column shrinking percentage that this temperature spot is corresponding, further proved pressure reduction and skyrocketed that the temperature place is softening to be finished, fusing is aggravation further, and obviously new evaluation method can better be estimated the soft heat characteristic of comprehensive furnace charge.

When having the molten state of the comprehensive furnace charge of optimum evaluation method evaluation now, the droplet temperature interval width is 92 ℃, and the softening temperature interval is 172 ℃ with the interval sum of droplet temperature, is worth little 55 ℃ than soft melting dropping temperature range.Have a NE dead zone between softening temperature interval and the droplet temperature interval, this dead zone accounts for 1/3 of soft melting dropping temperature range as seen from Figure 1, obviously, and the soft melting dropping characteristic of the comprehensive furnace charge of sign that so large difference can not be correct.When adopting new evaluation method to estimate, new evaluation method can not only be estimated melt temperature temperature at the interval whole story, interval width and stock column shrinking percentage, and can also estimate the maximum differential pressure of maximum differential pressure and unit stock column height in the pressure differential range, stock column melting process of the interval corresponding pressure differential range of melt temperature, unit stock column.Simultaneously, the new evaluating method can also be estimated the drippage temperature range of molten hot metal preferably, and the reflowing temperature of comprehensive furnace charge is interval, melt temperature is interval and drippage temperature range sum equals the soft melting dropping temperature range, and its value is 227 ℃.Obviously, the new evaluating method can accurately judge the melting finishing temperature according to unit stock column height pressure difference, can the more accurate hot properties of more fully estimating comprehensive furnace charge, more be of value to the adjustment of burden structure when instructing blast-furnace smelting.

Claims (1)

1. the evaluation method of an iron-containing charge high temperature soft melting dropping characteristic is characterized in that:

This evaluation method is with the soft melting dropping temperature range T of iron-containing charge _d-T _sBe divided into soft heat layer, melting layer and drippage layer, the soft heat layer is defined as soft heat and begins temperature to the interval corresponding iron-containing charge layer of soft heat finishing temperature, melting layer is defined as melting and begins temperature to the interval corresponding iron-containing charge layer of melting finishing temperature, and the drippage layer is defined as the melting finishing temperature to the right iron-containing charge layer of molten iron drippage temperature range;

Wherein, soft heat begins temperature T _s: the temperature that pressure reduction obviously raises or the stock column shrinking percentage obviously increases; Soft heat finishing temperature T _m: the temperature that pressure reduction begins to skyrocket; Melting begins temperature T _m: the temperature that pressure reduction begins to skyrocket; Melting finishing temperature Tp _Max: the temperature that maximum differential pressure is corresponding, when the poor peak of maximal pressure that has two pressure reduction to be more or less the same, select from nearest one of molten iron drippage temperature as the poor peak of maximal pressure; Molten iron drippage temperature T _d: the temperature that molten iron begins to drip in the stock column;

According to temperature and the pressure reduction parameter of the correspondence of soft heat layer, melting layer and drippage layer, iron-containing charge soft heat performance characteristic value SMD is proposed ₁, iron-containing charge melting behaviour eigenwert SMD ₂, iron-containing charge melt-dropping property eigenwert SMD ₃And begin to the corresponding soft melting dropping performance eigenwert of molten iron drippage temperature range SMD, according to SMD from the iron-containing charge soft heat ₁, SMD ₂, SMD ₃Judge each interval soft melting dropping performance of iron-containing charge and total soft melting dropping performance with the SMD value; SMD ₁, SMD ₂, SMD ₃Less with SMD, the soft melting dropping performance of iron-containing charge is better;

Its corresponding calculation formula is as follows:

${\mathrm{SMD}}_1={\&Integral;}_{T_s}^{T_m}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_s}{\overset{T_m}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}+T_i)---\left(1\right)$

Formula (1) expression soft heat performance characteristic value (SDM ₁) end to soft heat for soft heat begins temperature

Pressure reduction is along the integration of temperature, T in the temperature range _iThe expression soft heat begins the arbitrary temp value between temperature and the soft heat finishing temperature, △ P _iPressure difference corresponding to expression temperature T i;

${\mathrm{SMD}}_2={\&Integral;}_{T_m}^{T_{P\max }}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_m}{\overset{T_{P\max }}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}+T_i)---\left(2\right)$

Formula (2) expression melting behaviour eigenwert (SDM ₂) end to melting for melting begins temperature

Pressure reduction is along the integration of temperature, T in the temperature range _iThe expression melting begins the arbitrary temp value between temperature and the melting finishing temperature, △ P _iThe expression temperature T _iCorresponding pressure difference;

${\mathrm{SMD}}_3={\&Integral;}_{T_{P\max }}^{T_d}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}=\frac{1}{2}\underset{i=T_{P\max }}{\overset{T_d}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}+T_i)---\left(3\right)$

Formula (3) expression dropping performance eigenwert (SDM ₃) drip for the melting finishing temperature arrives molten iron

Pressure reduction is along the integration of temperature, T in the temperature range _iArbitrary temp value between expression melting finishing temperature and the molten iron drippage temperature, △ P _iThe expression temperature T _iCorresponding pressure difference;

$\mathrm{SMD}={\&Integral;}_{T_s}^{T_d}\mathrm{\&Delta;P}\left(T\right)\mathrm{dT}{=\mathrm{SMD}}_1+{\mathrm{SMD}}_2+{\mathrm{SMD}}_3=\frac{1}{2}\underset{i=T_s}{\overset{T_d}{\mathrm{\&Sigma;}}}(\mathrm{\&Delta;}{P}_{i+1}+\mathrm{\&Delta;}{P}_i)\&times;(T_{i+1}-T_i)---\left(4\right)$

Formula (4) expression soft melting dropping performance eigenwert (SDM) for begin from soft heat temperature in the drippage temperature range pressure reduction along the integration of temperature, T _iThe expression soft heat begins the arbitrary temp value between temperature and the drippage temperature, △ P _iThe expression temperature T _iCorresponding pressure difference.

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