CN105331808A - Method for iron ore powder agglomeration - Google Patents

Abstract

The invention discloses a method for iron ore powder agglomeration. The method aims at improving the iron grade of iron ore, reducing energy consumption and reducing environmental pollution. The method includes the steps that iron ore powder, limestone powder, magnesium cement and pore-forming agents are proportioned for iron ore powder briquettes; primary mixing is carried out, and the small-granularity iron ore powder, the limestone powder, the magnesium cement and the pore-forming agents are put in a mixer; secondary mixing is carried out, the primary mixture and the remaining large-granularity iron ore powder are put into the mixer to be mixed evenly to obtain a uniform mixture; the uniform mixture is placed in a cuboid-shaped mold to be pressed into an iron briquette raw material; the iron briquette raw material is roasted; and crushing and screening are carried out. According to the method, the magnesium cement serves as a binder and a MgO additive, the pore-forming agents are added to the mixture, the cold press molding technology is adopted for pressing multi-pore iron briquettes, and therefore the iron ore powder agglomeration efficiency is improved, the metallurgical performance of the iron briquettes is improved, the production technology process is simplified, the quantity of the binder used in sintering and palletizing is reduced, iron ore resources are expanded, and the bulk density of the iron briquettes and the production efficiency of a blast furnace are improved.

Description

A kind of method of iron mineral powder agglomeration

Technical field

The present invention relates to blast furnace raw material preparation method, particularly a kind of method of iron mineral powder agglomeration.

Background technology

Agglomeration of fine ore be directly can not enter stove metal mining powder after batching, cause the nugget meeting smelting requirements by artificial way.Agglomeration of fine ore is the important step that before smelting, raw material prepares, and it had both expanded the source of raw materials for metallurgy, which in turn improved the quality of raw material.

The main method of iron mineral powder agglomeration has sintering and pelletizing two kinds.Sintering is coordinated according to a certain percentage with fuel, flux by particulate iron-bearing material, add water-wet, mixing, then be distributed on sinter machine, by igniting, exhausting, and produce high temperature by fuel combustion in sintered material, and then a series of physical-chemical reaction occurs, generating portion low melting point, form the liquid phase of some amount, iron mineral wetting of particulates bonding is got up, after cooling, forms porous block product---the agglomerate with some strength.Fine ore is first added appropriate moisture by pelletizing and binding agent is made viscous consistency, had the green-ball of sufficient intensity, and roasting in oxidizing atmosphere after drying, preheating, makes green-ball conglomeration, make pellet.

Pellet formation technique is to usually processing the higher iron ore concentrate of the thinner grade of granularity, need in balling process to add binding agent wilkinite, pelletizing grade can be reduced like this and increase the blast furnace quantity of slag, and blast furnace uses pellet to need more than 1250 DEG C high temperature oxidation roastings, consume mass energy and discharge great amount of carbon dioxide, pellet structure is relatively fine and close simultaneously, and the relatively porous sintered ore deposit of reductibility is lower; Although sintering process can process the powdered iron ore of various grade, but sintering finished rate lower (only about 70%), capacity usage ratio low (sinter machine all exists about 50% air leak rate of air curtain), and sintering coke powder or coal dust produce a large amount of sulfide and nitride, pollutant atmosphere.Adding containing magnesium oxide material in current agglomerates of sintered pellets has not been cohesive action, has been to regulate the effect of agglomerates of sintered pellets metallurgical performance, and its interpolation adds agglomerates of sintered pellets cakingagent usage quantity, reduces the Iron grade of sintered balls nodulizing, adds energy expenditure.

Public announcement of a patent application CN104232884A, discloses a kind of method of iron mineral powder agglomeration, and the method can utilize resources synthetically, expands the raw material type of ironmaking, removes detrimental impurity, and reclaim beneficial element, protection of the environment, improves the metallurgical performance of ore.But the method still adopts simple conventional sintering chassis art breading, and metallurgical iron-containing waste produces agglomerate, production efficiency is lower, energy utilization is low, produce air-polluting a large amount of sulfide and nitride, metallurgical iron-containing waste is because production technique cause its composition different from production real condition fluctuates comparatively greatly simultaneously, thus easily causes sinter chemical composition to fluctuate.

Summary of the invention

The invention provides a kind of method of iron mineral powder agglomeration, be intended to improve iron ore Iron grade, conserve energy consumption, reduce environmental pollution.

The method of a kind of iron mineral powder agglomeration provided by the invention comprises the following steps:

A. iron ore powder agglomates batching: by weight percentage, powdered iron ore 85-90%, limestone powder 5-10%, magnesium cement 3-5%, pore-forming material 0.5%, be divided into two portions powdered iron ore wherein by granularity, and a part of granularity is 0-1mm, and a part of granularity is 1-5mm;

B. mixed once: put in mixing machine powdered iron ore that granularity is 0-1mm, the limestone powder of 5-10%, the magnesium cement of 3-5% and 0.5% pore-forming material, mixing time 3-5min, and in mixing process, add the water vapor of material total mass 2-4%, obtain mixed once material;

C. two mixing: the residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and mixed, mixing time 2-3min, and the water vapor adding material total mass 3-4% in mixing process, and be uniformly mixed material;

D. suppress: Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material;

E. high pressure roasting: iron block raw material are 2.0-8.0Mpa at pressure, temperature is roasting under the condition of 200-400 DEG C, and roasting time is 15-30min, removes chlorine element in iron block;

F. crushing and screening: by roasting iron block crushing and screening, what granularity was less than 5mm returns batching, and that 5-20mm is the dual alkalinity R=1.10-1.50 of finished product porous iron block, finished product porous iron block, and TFe weight percent content is 54-63%.

Magnesium cement in described step a is magnesia oxychloride cement, granularity≤200 order; Pore-forming material in described step a is ball-type plastic foam, and mean diameter is 0.1-2mm.

The present invention compared with existing similar technique, its significantly beneficial effect be embodied in:

With magnesium cement for binding agent and MgO additive, in compound, add pore-forming material, adopt coldmoulding technology, be pressed into porous iron block, improve iron mineral powder agglomeration efficiency, improve the metallurgical performance of iron block, simplify the technological process of production, reduce the use of cakingagent in agglomerates of sintered pellets (unslaked lime, wilkinite), improve iron ore Iron grade, decrease energy expenditure, extend iron ore deposit, improve volume density and the blast fumance efficiency of iron block, decrease environmental pollution.

Embodiment

The present invention is described in more detail below by embodiment.

Embodiment 1

By the requirement batching that dual alkalinity R=1.10, TFe content is 63%, by weight percentage: powdered iron ore 89.5%, limestone powder 5%, magnesium cement 5%, mean diameter are the ball-type plastic foam pore-forming material 0.5% of 0.1-2mm, powdered iron ore is wherein divided into two portions by granularity, part granularity is 0-1mm, and a part of granularity is 1-5mm; Put in mixing machine powdered iron ore that granularity is xx-yy, the limestone powder of 5%, the magnesium cement of 5% and 0.5% pore-forming material mixing, mixing time 3min, and the water vapor adding total mass 2% in mixing process, obtain mixed once material; The residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and is mixed, mixing time 2min, and the water vapor adding total mass 4% in mixing process, and be uniformly mixed material; Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material; Iron block raw material are 3.0Mpa at pressure, and temperature is under the condition of 200 DEG C, and roasting iron block is carried out crushing and screening by roasting 15min, obtain the finished product porous iron block that granularity is 5 ~ 20mm.

Embodiment 2

By the requirement batching that dual alkalinity R=1.50, TFe content is 55%, by weight percentage: powdered iron ore 84.5%, limestone powder 10%, magnesium cement 5%, mean diameter are the ball-type plastic foam pore-forming material 0.5% of 0.1-2mm, powdered iron ore is wherein divided into two portions by granularity, part granularity is 0-1mm, and a part of granularity is 1-5mm; Put in mixing machine powdered iron ore that granularity is 0-1mm, the limestone powder of 10%, the magnesium cement of 5% and 0.5% pore-forming material mixing, mixing time 5min, and the water vapor adding total mass 3% in mixing process, obtain mixed once material; The residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and is mixed, mixing time 3min, and the water vapor adding total mass 4% in mixing process, and be uniformly mixed material; Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material; Iron block raw material are 4.0Mpa at pressure, and temperature is under the condition of 260 DEG C, and roasting iron block is carried out crushing and screening by roasting 20min, obtain the finished product that granularity is 5 ~ 20mm.

Embodiment 3

By the requirement batching that dual alkalinity R=1.20, TFe content is 59%, by weight percentage: powdered iron ore 89.5%, limestone powder 6%, magnesium cement 4%, mean diameter are the ball-type plastic foam pore-forming material 0.5% of 0.1-2mm, powdered iron ore is wherein divided into two portions by granularity, part granularity is 0-1mm, and a part of granularity is 1-5mm; Put in mixing machine powdered iron ore that granularity is 0-1mm, the limestone powder of 6%, the magnesium cement of 4% and 0.5% pore-forming material mixing, mixing time 4min, and the water vapor adding total mass 3% in mixing process, obtain mixed once material; The residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and is mixed, mixing time 2min, and the water vapor adding total mass 4% in mixing process, and be uniformly mixed material; Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material; Iron block raw material are 8.0Mpa at pressure, and temperature is under the condition of 400 DEG C, and roasting iron block is carried out crushing and screening by roasting 30min, obtain the finished product that granularity is 5-20mm.

Embodiment 4

By the requirement batching that dual alkalinity R=1.30, TFe content is 60%, by weight percentage: powdered iron ore 87.5%, limestone powder 8%, magnesium cement 3%, mean diameter are the ball-type plastic foam pore-forming material 0.5% of 0.1-2mm, powdered iron ore is wherein divided into two portions by granularity, part granularity is 0-1mm, and a part of granularity is 1-5mm; Put in mixing machine powdered iron ore that granularity is 0-1mm, the limestone powder of 8%, the magnesium cement of 3% and 0.5% pore-forming material mixing, mixing time 3min, and the water vapor adding total mass 2% in mixing process, obtain mixed once material; The residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and is mixed, mixing time 2min, and the water vapor adding total mass 4% in mixing process, and be uniformly mixed material; Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material; Iron block raw material are 6.0Mpa at pressure, and temperature is under the condition of 300 DEG C, and roasting iron block is carried out crushing and screening by roasting 25min, obtain the finished product that granularity is 5-20mm.

Table 1 embodiment effect

Embodiment	TFe％	Yield rate %	Rotary drum coefficient	FeO％	Reduction degree
						Embodiment 1	63.01	94.67	93.34	2.12	86.34
Embodiment 2	56.23	93.33	90.34	1.34	89.23
						Embodiment 3	59.23	90.45	89.34	3.12	84.37
Embodiment 4	60.12	88.67	84.34	4.34	83.56

Claims (2)

1. a method for iron mineral powder agglomeration, is characterized in that the method comprises the following steps:

A. iron ore powder agglomates batching: by weight percentage, powdered iron ore 85-90%, limestone powder 5-10%, magnesium cement 3-5%, pore-forming material 0.5%, be divided into two portions powdered iron ore wherein by granularity, and a part of granularity is 0-1mm, and a part of granularity is 1-5mm;

B. mixed once: put in mixing machine powdered iron ore that granularity is 0-1mm, the limestone powder of 5-10%, the magnesium cement of 3-5% and 0.5% pore-forming material, mixing time 3-5min, and in mixing process, add the water vapor of material total mass 2-4%, obtain mixed once material;

C. two mixing: the residue powdered iron ore being 1-5mm by mixed once material and granularity is put into mixing machine and mixed, mixing time 2-3min, and the water vapor adding material total mass 3-4% in mixing process, and be uniformly mixed material;

D. suppress: Homogeneous phase mixing material is put into rectangular shape mould and is pressed into iron block raw material;

E. high pressure roasting: iron block raw material are 2.0-8.0Mpa at pressure, temperature is roasting under the condition of 200-400 DEG C, and roasting time is 15-30min, removes chlorine element in iron block;

F. crushing and screening: by roasting iron block crushing and screening, what granularity was less than 5mm returns batching, and that 5-20mm is the dual alkalinity R=1.10-1.50 of finished product porous iron block, finished product porous iron block, and TFe weight percent content is 54-63%.

2. the method for a kind of iron mineral powder agglomeration according to claim 1, is characterized in that the magnesium cement in step a is magnesia oxychloride cement, granularity≤200 order; Pore-forming material in step a is ball-type plastic foam, and mean diameter is 0.1-2mm.