CN1070237C - Process for making acidic spheroidized ore - Google Patents

Abstract

The present invention relates to a process for making an acidic spheroidized ore. In the present invention, a high-grade iron ore concentrate is used as a raw material, bentonite is used as a binding agent, a coal powder instead of gas or liquid fuel is adopted for the combustion of material layers, a consolidatation mechanism for acidic spheroidized ores is adopted, and a sintering machine is adopted to produce the acidic spheroidized ore; the present invention has the advantages that the present invention improves the structures of blast furnace charges, and saves investment by 85% or so; in addition, the present invention has the advantages of high output and low energy consumption, the utilization coefficient of the sintering machine is 1.5 to 1.7 t/m<2>. h, the solid energy consumption is 50 Kg/t. p, and the fuel consumption is 50 Kg/t. P; the spheroidized ore has the advantages of high iron grade (TFe is more than 60%), high intensity (ISO drum strength is more than or equal to 70%), good reducibility (RI is more than 55%) and low reduction degradation index at a low temperature (RDI<+3.15> is more than or equal to 75%).

Description

A kind of acid pellet manufacturing method

The invention relates to a method for manufacturing blast furnace ironmaking raw materials.

At present, the conventional blast furnace ironmaking raw materials at home and abroad can be divided into acid pellets and sintered ore, and the production methods of acid pellets can be divided into shaft furnace pellet method, belt machine roasting method, chain grate machine-rotary kiln method three Generally, gas fuel or liquid fuel is used to provide the heat source required for pellet roasting. Some domestic manufacturers also use solid fuel coal powder combustion for the shaft furnace pellet roasting method, but the combustion of coal powder is carried out outside the furnace. The consolidation mechanism of the above methods is solid phase diffusion bonding, which has the disadvantages of high material requirements, large investment, high production cost, and easy ring formation in the kiln. Chinese patent application (application number 98102028) proposes a method for producing acidic pellet sintered ore with a sintering machine. charge) bonded into sinter, but the generated sinter has poor reducibility, poor strength, and low grade, which is not conducive to strengthening blast furnace smelting.

In order to solve the above deficiencies, the present invention provides a method for producing acid pellets by utilizing the consolidation mechanism of acid pellets and using a sintering machine.

The invention uses high-grade iron ore concentrate (TFe63～66%, SiO ₂ <5.5%) as raw material, adds bentonite as binder, adopts coal powder to directly blend into the material layer for combustion, utilizes the consolidation mechanism of acidic pellets, adopts The sintering machine produces acid pellets, including batching, pelletizing, drying, ignition, roasting, crushing, screening and other processes. The specific process is as follows:

a> Use bentonite as binder, strengthen pelletizing and pellet roasting, the ratio of bentonite is 1.0-2.0% (percentage by weight, the same below), use solid fuel pulverized coal instead of gaseous fuel or liquid fuel, and the ratio of pulverized coal is 3.5 ~4.5% (weight percentage) (particle size<3mm), wherein the proportion of internally blended coal powder is 1.2-1.5% during pelletizing.

b> After pelletizing, the ratio of external coal powder is 2.3-3.0%. Burning speed of pulverized coal in the layer.

c>The particle size of green balls should be 5-15 mm ≥ 80%, the water content of green balls should be 7.5-10%, the compressive strength of green balls should be ≥ 10 N/piece, and the drop strength of green balls should be ≥ 4.5 times/0.5 meters.

d>The height of the material layer is 500-700mm, and the drying section is set before ignition and roasting. The drying time accounts for 5-20% of the roasting time, and the drying temperature is 200-300°C. The pellet cooling waste gas or igniter waste gas is used as the heat source.

e>Ignition time 1-2min, ignition temperature 1150±50°C, ignition negative pressure 4000-6000Pa, roasting negative pressure 8000-10000Pa, vertical roasting speed controlled at 15-20mm/min.

The invention utilizes the consolidation mechanism of the acid pellets to ensure the solid phase diffusion and consolidation of the acid pellets. The pellets are mainly composed of solid phase diffusion and consolidation of Fe ₃ O ₄ or Fe ₂ O ₃ recrystallization, glass only accounts for 4-5%, and a very small amount of fayalite. It has the following advantages: 1. It is suitable for small and medium-sized factories to carry out technological transformation, improve the structure of blast furnace charge, save investment, and have quick results. It is only necessary to transform the old sintering machine, easy to promote, and save about 85% of investment; 2. High output and low energy consumption, the utilization coefficient of sintering machine roasting acid pellets is 1.5～1.7t/m ² h, the solid energy consumption is 50Kg/t·p, while the utilization coefficient of belt roaster is only 0.8～1.0t/ m ² ·h, the fuel consumption is 50Kg/t·P, that is to say, the production of acid pellets roasted by the belt sintering machine is doubled, while the energy consumption is equal; 3. Pellet ore has high iron grade (TFe>60%), high strength (ISO drum strength≥70%), good reducibility (RI>55%), low low-temperature reduction pulverization rate (RDI _+3.15 ≥75%), Good strength after reduction at 900°C (-3.15mm<20%).

Description of drawings:

Fig. 1: Process flow chart of the present invention.

Example:

1. Iron concentrate (TFe 65.38%, SiO ₂ 4.8 3%) is mixed with 1% bentonite and 2% anthracite powder (-1mm accounts for 88.68%) and 20% returned ore, and then mixed on the Φ1m disc pelletizer For pelletizing, the particle size of green pellets is 5-15mm≥80%, the moisture content of green pellets is 8.5%, and the raw pellets are mixed with 2.5% anthracite coal powder in a cylinder mixer for 3 minutes, and then dried in a Φ250mm sintering cup for 2 minutes (drying temperature 250°C , drying negative pressure 5000Pa), ignition for 2min (ignition temperature 1150±50°C, ignition negative pressure 4000Pa), roasting negative pressure 8000Pa, material layer height 700mm, vertical roasting speed controlled at 14-20mm/min, under the above conditions, sintering On-board pellet production (utilization coefficient) reaches 1.67t/m ² h, drum strength of pellets (ISO) ≥ 70%, finished product rate 70-80%, solid energy consumption 55-60Kg/t·p, pellets Agglomerate grade TFe 62.83%, FeO 10-13%, reduction (RI) 55-68%, low-temperature reduction powder rate RDI _+3.15 80%, strength after reduction at 900°C -3.15mm is 20%.

Claims (2)

1. process for making acidic spheroidized ore, comprise batching, make ball, drying, igniting, roasting, fragmentation, screening, it is characterized in that: the present invention is raw material with the high grade iron concentrate, add wilkinite and make binding agent, adopt coal dust directly to allocate bed of material burning into, utilize the acidic pellet ore consolidation mechanism, adopt sinter machine to produce acidic pellet ore, concrete processing parameter is as follows:

A＞use wilkinite is made binding agent, wilkinite proportioning 1.0～2.0% (weight percent), use solid fuel coal dust place of gas fuel or liquid fuel, coal powder size＜3mm, proportioning is 3.5～4.5% (weight percents), and interior coal blending powder proportioning is 1.2～1.5% when wherein making ball;

Outer coal blending powder proportioning is 2.3～3.0% behind d＞the make ball, and employing garden dish pelletizer is made ball, then in the tube mixing machine of garden with coal dust and pelletizing mixing;

C＞green-ball granularity control 5～15mm 〉=80%, green-ball moisture 7.5～10%;

D＞bed depth is 500～700mm, before the igniting roasting dryer section is set, and accounts for 5～20% of roasting time time of drying, and 200～300 ℃ of drying temperatures are thermal source with pellet cooling exhaust or lighter for ignition waste gas;

E＞ignition time 1～2min, 1150 ± 50 ℃ of ignition temperatures, igniting negative pressure 4000～6000Pa, roasting negative pressure 8000～10000Pa, vertical rate of roasting is controlled at 15～20mm/min.

2. method according to claim 1 is characterized in that: described high grade iron concentrate is TFe63～66%, SiO ₂＜5.5% iron ore concentrate.