CN104726699B - High-strength composite metallized pellet produced by using metallurgical iron-containing dust and production process thereof - Google Patents

Abstract

The invention relates to the technical field of metallurgy and mineral engineering, and discloses a high-strength composite metallized pellet produced by utilizing metallurgical iron-containing dust and mud and a production process thereof. The iron-containing metallurgical dust-mud comprises blast furnace gas ash, converter OG mud and converter secondary dust according to the mass ratio of 650: 580 to 610: 55-70, wherein the shell is prepared by mixing iron ore concentrate and bentonite according to a mass ratio of 650: 13-18, wherein the mass ratio of the metallurgical iron-containing dust mud to the iron ore concentrate is 60-65: 35-40, the granularity of the inner core is 20-25 mm, and the thickness of the shell is 5-10 mm. The production process comprises the steps of preparing a core, wrapping a shell to form a composite metallized pellet, distributing and drying the composite metallized pellet, reducing and roasting the composite metallized pellet, cooling and sorting the high-temperature reduced composite metallized pellet and the like. The composite metallized pellet prepared by the method has the metallization rate of more than 90 percent and the compressive strength of more than 1600N/pellet, recycles the waste metallurgical iron-containing dust and mud, and reduces the environmental pollution.

Description

High-strength composite metallized pellets produced by metallurgical iron-containing dust and its production craft

technical field

The invention relates to the technical field of metallurgy and mineral engineering, and discloses a high-strength composite metallized pellet produced by using metallurgical iron-containing dust and sludge and a production process thereof.

Background technique

Metallurgical iron-containing dust is a solid iron-containing material with many types and complex components produced in the production process of the iron and steel industry. The total production accounts for about 5-6% of the iron and steel output. Gas ash, converter OG mud, steelmaking dust, casthouse dust collection, etc. The main component of metallurgical iron-bearing dust is iron, with an iron content of 30-65%, a carbon content of 15-35%, and a certain amount of alkali metal elements such as K, Na, and Zn.

In iron and steel enterprises, Zn in ironmaking and steelmaking dust mainly exists in the form of ZnO. When metallurgical iron-containing dust is used for sintering and adding, the ZnO contained in the material will still remain in the sinter, eventually resulting in zinc The cyclic enrichment in the blast furnace affects the normal production of the blast furnace. Therefore, except for some metallurgical iron-containing dust sludge used in sintering ingredients, the rest of the dust sludge has accumulated in large quantities and has not been developed and utilized.

At present, rotary hearth furnaces are mainly used at home and abroad to directly reduce metallurgical dust and sludge. The metallized pellets produced are used in ironmaking blast furnaces or steelmaking converters. There is a large investment, with a single investment of about 200 million yuan and a single processing capacity. About 200,000 tons/year, the metallization rate is about 65%, and it has not been widely used.

Contents of the invention

The purpose of the present invention is to provide a high-strength composite metallized pellet produced by utilizing metallurgical iron-containing dust and its production process, and use the discarded metallurgical iron-containing dust as a production raw material to produce composite metallized pellets, which are used for blast furnaces. Adjust the charge structure to provide metallized charge to solve the problem that a large amount of metallurgical iron-containing dust cannot be recycled.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A high-strength composite metallized pellet produced by metallurgical iron-containing dust and used for blast furnace or converter smelting charge, it includes an inner core and a shell wrapped outside the inner core, the inner core is composed of metallurgical iron-containing dust, the Metallurgical iron-containing dust is composed of blast furnace gas ash, converter OG mud, and converter secondary dedusting ash in a mass ratio of 650:580-610:55-70. The shell is made of iron concentrate and bentonite in a mass ratio It is mixed in the ratio of 650:13-18, the mass ratio of the metallurgical iron-containing dust and the iron concentrate is 60-65:35-40, the particle size of the inner core is 20-25mm, and the outer shell The thickness is 5 ~ 10mm.

As a further improvement of the present invention, the outside of the shell is also covered with a layer of reducing agent.

As a further improvement of the present invention, the reducing agent is coal powder, the mass of which is 5-8% of the mass of the iron concentrate in the shell, and the mass percentage of coal powder particles with a particle size of -120 mesh is greater than 80%.

As a further improvement of the present invention, the iron grade of the iron concentrate is 54-66%, the SiO ₂ content is 2-15%, and the mass percentage content of the iron concentrate particles with a particle size of -200 mesh is greater than 80%.

As a further improvement of the present invention, the mass percentages of fixed carbon, ash and volatile matter in the coal powder are 72-76:11-15:11-14.

As a further improvement of the present invention, the metallization rate in the high-strength composite metallized pellets is greater than 90%, and the compressive strength is greater than 1600N/ball.

A kind of production technology of the high-strength composite metallized pellet that utilizes metallurgical iron-containing dust to produce as above, it comprises the following steps:

Step 1. Prepare the inner core. Blast furnace gas ash, converter OG mud, and converter secondary dedusting dust are mixed according to the mass ratio of 650:580-610:55-70 and mixed evenly to form metallurgical iron-containing dust sludge for preparing the inner core. Metallurgical iron-containing dust is added to the disc pelletizer, and 7-10% of the total mass of the mixture is added to carry out disc or cylinder pelletization, and the particle size of the inner core is controlled to be 20-25mm;

Step 2. Wrap the outer shell to form a composite metallized pellet. Mix the iron concentrate and bentonite according to the mass ratio of 650:13-18 and mix evenly. Put the inner core produced in step 1 into the mixed material. Ball discs or cylinders evenly wrap the mixed material on the outer wall of the inner core to form the outer shell, the thickness of the outer shell is 5-10 mm, and wet composite metallized pellets with a particle size of 25-35 mm are obtained, wherein step 1 The mass ratio of the metallurgical iron-containing dust to the iron concentrate is 60-65:35-40;

Step 3: The outer wall of the composite metallized pellets is wrapped with a reducing layer, and the wet composite metallized pellets prepared in the step 2 are put into coal powder whose mass is 5-8% of the iron concentrate mass, and a disc pelletizer is used Cover the outside evenly with a layer of coal powder to form a reduction layer;

Step 4. Cloth and drying of the composite metallized pellets. Lay a layer of 10-20mm thick residual carbon or coal with low volatile content on the bottom and periphery of the kiln car of the reduction kiln, and grade and layer the composite metallized pellets. The cloth is laid on the kiln car, and a layer of 10-20mm thick covering coal is laid on the upper surface of the composite metallized pellets, and left to dry;

Step 5: Reduction roasting of composite metallized pellets. The dried composite metallized pellets undergo direct reduction and high-temperature consolidation at a temperature of 1150-1250°C and a reduction time of 90-120 minutes in a reduction kiln to obtain high-temperature reduction composite metallization pellets;

Step 6. Cooling and sorting of the high-temperature reduction composite metallized pellets. The high-temperature reduction composite metallization pellets obtained in step 5 are anaerobically cooled to room temperature and then sorted from magnetic materials and non-magnetic materials to obtain a metallization rate greater than 90. %, high-strength composite metallized pellet products with compressive strength greater than 1600N/ball.

As a further improvement of the present invention, when the composite metallized pellets are reduced and roasted using an external reducing agent, the step three can be omitted, and the step five is based on iron For the grade of the concentrate, 15-20% of the weight of the composite metallized pellets is mixed into the reduction kiln with reduced coal.

As a further improvement of the present invention, the reduction kiln is a tunnel kiln, a car bottom furnace or a chamber furnace.

The principle of determining the particle size of the composite metallized pellets in the present invention: after the large-size pellets are distributed in the reduction furnace, the pores between the pellets are relatively large, which is beneficial to the radiation heat transfer between the upper and lower layers of the pellets, Reduce the heat transfer resistance of the material and the temperature difference between the upper and lower layers of the material, so that the entire material can be uniformly reduced along the thickness direction, and realize the reduction roasting of the thick material layer. However, when the particle size of the pellet exceeds 40 mm, due to the increase of the internal heat transfer resistance of the pellet and the need to absorb a certain amount of heat for the reduction of the pellet, the temperature difference between the inside and outside of the pellet increases accordingly, and the reduction temperature of the inner core is low, which affects The restore speed and restore quality of the kernel. When the particle size of the pellets is less than 20mm, the proportion of ironmaking and steelmaking dust and sludge in the pellets is small, the amount of metallurgical iron-containing dust and sludge treated by the present invention decreases, and the radiation heat transfer between the pellets decreases simultaneously. It is not conducive to the reduction of pellets in thick material layers. In addition, when the composite metallized pellets produced by the present invention are used as blast furnace charge, in order to improve the air permeability of the blast furnace, the particle size of the metallized pellets should be as large as possible. Therefore, the particle size of the composite metallized pellets of the present invention is selected to be 25-35 mm.

In the present invention, the core of the composite metallized pellet is made of blast furnace gas ash, converter OG mud, and secondary dust removal dust of the converter. Potassium and sodium mainly exist in the form of potassium carbonate or sodium carbonate in the composite metallized pellet. The melting point of potassium is 891°C, and the melting point of sodium carbonate is 854°C. When potassium carbonate and sodium carbonate are dissolved in the mixture, the mixture will expand. In the present invention, by adjusting the ratio of three metallurgical iron-containing dust sludges in the core, blast furnace gas ash, converter OG mud, and converter secondary dedusting dust, the carbon content in the blast furnace gas dust is higher, and the iron grade and CaO content in the converter OG mud are higher. , the high content of SiO ₂ in the secondary dedusting dust of the converter makes the core of the composite metallized pellets, which can form a certain slag phase during the high-temperature reduction process and weaken the tendency of the mixed material to expand; at the same time, wrap a layer on the outer surface of the core The shell composed of iron concentrate and bentonite, the iron concentrate is first reduced to metallic iron during high-temperature roasting, and the metallic iron crystallizes to form a metal shell with a certain strength, which can effectively inhibit the expansion of the inner core and keep the entire composite metallized pellet Complete spherical shape, and has high strength.

The composite metallized pellet reduction process of the present invention not only utilizes the original carbon in the ingredients of the inner core, but also uses the technology of wrapping reducing agent to wrap a reduction layer composed of coal on the surface of the wet ball, which can make the composite metal with large particle size The pellets are uniformly reduced inside and outside at the same time during the high-temperature reduction process, which speeds up the reduction speed and shortens the reduction time.

The metallurgical iron-containing dust sludge used in the present invention contains relatively high zinc oxide. Under the high temperature and reducing atmosphere of the reduction furnace, zinc oxide is reduced to metallic zinc. Since the melting point of metallic zinc is 419.53°C and the boiling point is 907°C , the generated metal zinc is gasified at high temperature in the furnace, and is discharged with the flue gas in the form of zinc vapor. Zinc vapor is oxidized again during the cooling process of the flue gas, and forms zinc oxide solid particles. After the zinc oxide is collected, a by-product containing 40-65% zinc oxide can be obtained. Therefore, in the production process of metallized pellets, this process has the functions of dezincification and zinc collection.

In the present invention, in the production of kernels by using blast furnace gas ash, converter OG mud, and converter secondary dedusting ash mixture materials, according to the characteristics of converter OG mud with fine particle size and high CaO content, the kernel is produced without adding a binder production, reducing production costs.

The beneficial effects of the present invention are:

(1) The present invention makes effective use of metallurgical iron-containing dust and sludge produced by iron and steel enterprises, reduces the environmental pollution caused by the accumulation of metallurgical iron-containing dust and sludge, and the investment of a single production line of the process described in the present invention is small, only 20 million Yuan/piece, the annual production capacity can reach 100,000 to 150,000 tons;

(2) The production process of large-size composite pellets according to the present invention solves the problems of internal heat transfer and uneven reduction quality in the reduction process of composite metallized pellets, and can make the metallization rate of composite metallized pellets Reaching more than 90%, the thick furnace charge has good air permeability during the blast furnace mixing process, and the alkali metal removal rate of the composite metallized pellets is high, which increases the usage of the blast furnace mixing metallurgical iron-containing dust;

(3) The present invention solves the expansion problem of metallurgical iron-containing dust and sludge in the reduction roasting process by wrapping iron concentrate outside the inner core of composite metallized pellets to form composite pellets;

(4) The present invention produces composite metallized pellets through direct reduction treatment of metallurgical iron-containing dust and sludge, which provides metallized charge for adjusting the charge structure of the blast furnace, further reduces the ratio of coke into the furnace, and the ratio of the charge into the blast furnace reaches 10% The focal ratio can be reduced by 8%.

Description of drawings

Fig. 1 is the structural representation of utilizing metallurgical iron-containing dust and sludge to produce high-strength composite metallized pellets in Example 1;

Fig. 2 is the process flow diagram of utilizing metallurgical iron-containing dust and sludge to produce high-strength composite metallized pellets in Example 1;

Fig. 3 is the structural representation of utilizing metallurgical iron-containing dust and sludge to produce high-strength composite metallized pellets in Example 2;

Fig. 4 is a process flow chart of producing high-strength composite metallized pellets by using metallurgical iron-containing dust and sludge in Example 2.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Example 1

As shown in Figure 1, a high-strength composite metallized pellet produced by utilizing metallurgical iron-containing dust is used for blast furnace or converter smelting charge, and it includes a core 1 and a shell 2 wrapped outside the core 1. Composed of iron-containing dust and sludge, metallurgical iron-containing dust and sludge are composed of blast furnace gas ash, converter OG sludge, and converter secondary dedusting ash in a mass ratio of 650:580-610:55-70, and the shell 2 is made of iron concentrate It is mixed with bentonite at a mass ratio of 650:13-18, the mass ratio of metallurgical iron-containing dust and iron concentrate is 60-65:35-40, the particle size of the inner core 1 is 20-25mm, and the outer shell 2 The thickness is 5-10mm. The outside of the casing 2 is also covered with a layer of coal powder as the reducing agent 3 . The mass of the coal powder is 5-8% of the mass of the iron concentrate in the shell 2, and the mass percentage of the coal powder particles with a particle size of -120 mesh is greater than 80%.

The iron grade of the iron concentrate is 54-66%, the SiO ₂ content is 2-15%, and the mass percentage content of the iron concentrate particles with a particle size of -200 mesh is greater than 80%.

The mass percentages of fixed carbon, ash and volatile matter in coal powder are 72-76:11-15:11-14.

The metallization rate of high-strength composite metallized pellets is greater than 90%, and the compressive strength is greater than 1600N/ball.

A kind of production technology of the high-strength composite metallized pellet that utilizes metallurgical iron-containing dust to produce as shown in Figure 2, it comprises the following steps:

Step 1. Prepare the inner core. Blast furnace gas ash, converter OG mud, and converter secondary dedusting dust are mixed according to the mass ratio of 650:580-610:55-70 and mixed evenly to form metallurgical iron-containing dust sludge for preparing the inner core. Metallurgical iron-containing dust is added to the disc pelletizer, and 7-10% of the total mass of the mixture is added to carry out disc or cylinder pelletization, and the particle size of the inner core is controlled to be 20-25mm;

Step 2. Wrap the outer shell to form a composite metallized pellet. Mix the iron concentrate and bentonite according to the mass ratio of 650:13-18 and mix evenly. Put the inner core produced in step 1 into the mixed material. The ball disc or cylinder evenly wraps the mixed material on the outer wall of the inner core to form a shell with a thickness of 5-10 mm to obtain wet composite metallized pellets with a particle size of 25-35 mm. In step 1, metallurgical iron-containing dust The mass ratio of mud to iron concentrate is 60-65:35-40;

Step 3: Wrap the reduction layer on the outer wall of the composite metallized pellets, put the wet composite metallized pellets prepared in step 2 into the coal powder with a mass of 5% to 8% of the iron concentrate mass, and use a disc pelletizer to make it The outside is evenly covered with a layer of coal powder to form a reduction layer;

Step 4. Cloth and drying of the composite metallized pellets. Lay a layer of 10-20mm thick residual carbon or coal with low volatile content on the bottom and periphery of the kiln car of the reduction kiln, and grade and layer the composite metallized pellets. The cloth is laid on the kiln car, and a layer of 10-20mm thick covering coal is laid on the upper surface of the composite metallized pellets, and left to dry;

Step 5: Reduction roasting of composite metallized pellets. The dried composite metallized pellets undergo direct reduction and high-temperature consolidation at a temperature of 1150-1250°C and a reduction time of 90-120 minutes in a reduction kiln to obtain high-temperature reduction composite metallization pellets;

Step 6. Cooling and sorting of the high-temperature reduction composite metallized pellets. The high-temperature reduction composite metallization pellets obtained in step 5 are anaerobically cooled to room temperature and then sorted from magnetic materials and non-magnetic materials to obtain a metallization rate greater than 90. %, high-strength composite metallized pellet products with compressive strength greater than 1600N/ball.

Example 2

As shown in Figure 3, a high-strength composite metallized pellet produced by metallurgical iron-containing dust is used for blast furnace or converter smelting charge. It includes a core 1 and a shell 2 wrapped outside the core 1. It is characterized in that: The inner core 1 is composed of metallurgical iron-containing dust, and the metallurgical iron-containing dust is composed of blast furnace gas ash, converter OG mud, and converter secondary dedusting ash in a mass ratio of 650:580-610:55-70. The shell 2 It is made by mixing iron concentrate and bentonite according to the mass ratio of 650:13-18, the mass ratio of metallurgical iron-containing dust and iron concentrate is 60-65:35-40, and the particle size of core 1 is 20-25mm , the thickness of the shell 2 is 5-10mm.

The iron grade of the iron concentrate is 54-66%, the SiO ₂ content is 2-15%, and the mass percentage content of the iron concentrate particles with a particle size of -200 mesh is greater than 80%.

The metallization rate of high-strength composite metallized pellets is greater than 90%, and the compressive strength is greater than 1600N/ball.

A kind of production technology of the high-strength composite metallized pellet that utilizes metallurgical iron-containing dust to produce as shown in Figure 4, it comprises the following steps:

Step 1. Prepare the inner core. Blast furnace gas ash, converter OG mud, and converter secondary dedusting dust are mixed according to the mass ratio of 650:580-610:55-70 and mixed evenly to form metallurgical iron-containing dust sludge for preparing the inner core. Metallurgical iron-containing dust is added to the disc pelletizer, and 7-10% of the total mass of the mixture is added to carry out disc or cylinder pelletization, and the particle size of the inner core is controlled to be 20-25mm;

Step 2. Wrap the outer shell to form a composite metallized pellet. Mix the iron concentrate and bentonite according to the mass ratio of 650:13-18 and mix evenly. Put the inner core produced in step 1 into the mixed material. The ball disc or cylinder evenly wraps the mixed material on the outer wall of the inner core to form a shell with a thickness of 5-10 mm to obtain wet composite metallized pellets with a particle size of 25-35 mm. In step 1, metallurgical iron-containing dust The mass ratio of mud to iron concentrate is 60-65:35-40;

Step 3. Cloth and drying of the composite metallized pellets. Lay a layer of 10-20mm thick residual carbon or coal with low volatile content on the bottom and periphery of the kiln car of the reduction kiln. The composite metallized pellets are graded and layered. The cloth is laid on the kiln car, and a layer of 10-20mm thick covering coal is laid on the upper surface of the composite metallized pellets, and left to dry;

Step 4: Reduction roasting of the composite metallized pellets. The dried composite metallized pellets undergo direct reduction and high-temperature consolidation at a temperature of 1150-1250°C and a reduction time of 90-120 minutes in the reduction kiln. Grade, during reduction roasting in the reduction kiln, 15-20% of the weight of composite metallized pellets is mixed with reduced coal to obtain high-temperature reduced composite metallized pellets;

Step 5. Cooling and sorting of the high-temperature reduction composite metallized pellets. The high-temperature reduction composite metallization pellets obtained in step 4 are anaerobically cooled to room temperature and then sorted between magnetic materials and non-magnetic materials to obtain a metallization rate greater than 90. %, high-strength composite metallized pellet products with compressive strength greater than 1600N/ball.

In the above two embodiments, the reduction kiln is a tunnel kiln or a car bottom furnace or a chamber furnace.

The present invention produces high-strength composite metallized pellets by using metallurgical iron-containing dust and sludge, the metallization rate of which reaches more than 90%, and the compressive strength is greater than 1600N/ball, which can meet the use requirements of the blast furnace for adding furnace charges, and the discarded metallurgical Recycling and utilization of iron-containing dust realizes energy saving and emission reduction, and reduces environmental pollution.

Claims (7)

1. the high-intensity composite metal pellet that a kind of utilization iron containing metallurgical dust produces, for blast furnace or converter smelting furnace charge, It includes kernel（1）, be wrapped in kernel（1）Outside shell（2）It is characterised in that：Described kernel（1）By iron containing metallurgical dust Composition, described iron containing metallurgical dust is 650 by blast furnace dust, converter OG sludge, secondary BOF dedusting system ash in mass ratio：580～ 610：55～70 ratio mixes, described shell（2）It is 650 in mass ratio by iron ore concentrate and bentonite：13～18 ratio Example mixes, and described iron containing metallurgical dust is 60～65 with the mass ratio of described iron ore concentrate：35～40, described kernel（1）'s Granularity is 20～25mm, described shell（2）Thickness be 5～10mm；Described shell（2）Outside be also covered with one layer of reducing agent （3）；Described reducing agent（3）For coal powder, its quality is described shell（2）The 5～8% of middle Iron Concentrate Quality, wherein granularity be- The mass percentage content of the coal powder particles of 120 mesh is more than 80%.

2. the high-intensity composite metal pellet that utilization iron containing metallurgical dust according to claim 1 produces, its feature exists In：The Iron grade of described iron ore concentrate is 54～66%, SiO₂Content 2～15%, wherein granularity are the iron ore concentrate granule of -200 mesh Mass percentage content is more than 80%.

3. the high-intensity composite metal pellet that utilization iron containing metallurgical dust according to claim 1 produces, its feature exists In：In described coal powder, fixed carbon, ash, the mass percent of volatile matters are 72～76：11～15：11～14.

4. the high-intensity composite metal pellet that utilization iron containing metallurgical dust according to claim 1 produces, its feature exists In：In described high-intensity composite metal pellet, degree of metalization is more than 90%, and comprcssive strength is more than 1600N/ ball.

5. the production of the high-intensity composite metal pellet that a kind of utilization iron containing metallurgical dust according to claim 1 produces Technique it is characterised in that：It comprises the following steps：

Step one, prepare kernel, blast furnace dust, converter OG sludge, secondary BOF dedusting system ash are in mass ratio 650：580～ 610：55～70 ratio dispensing kernel iron containing metallurgical dust is prepared in mix homogeneously formation, is added to iron containing metallurgical dust In disc balling machine, add the moisture of mixed material gross mass 7～10% to carry out disk or cylinder pelletizing, control the granularity of kernel For 20～25mm；

Step 2, parcel shell form composition metal pellet, and iron ore concentrate and bentonite are 650 in mass ratio：13～18 Ratio dispensing mix homogeneously, the kernel that step one is produced is put in this mixed material, will using pelletizing disk or cylinder Mixed material is uniformly wrapped on the outer wall of described kernel, forms described shell, the thickness of shell is 5～10mm, obtains granularity Wet composition metal pellet for 25～35mm, the mass ratio of iron containing metallurgical dust and described iron ore concentrate wherein described in step one For 60～65：35～40；

Step 3, composition metal pellet outer wall parcel reducing zone, by the wet composition metal pellet of preparation in described step 2 Put in the coal powder that quality is Iron Concentrate Quality 5～8%, its outside one layer of coal powder of uniform fold made using disc balling machine, Form reducing zone；

Step 4, the cloth of composition metal pellet and drying, lay one layer of 10～20mm in the kiln car bottom of reduction kiln, periphery The carbon residue of thickness or the relatively low coal of volatile matters, composition metal pellet is laid on kiln car by the way of hierarchical classification cloth On, the capping coal of one layer of 10～20mm thickness, standing and drying is laid in the upper epidermis of composition metal pellet；

Step 5, the reduction roasting of composition metal pellet, dried composition metal pellet is in reduction kiln through excess temperature 1150～1250 DEG C, the direct-reduction of recovery time 90～120min and high-temperature concretion, obtain high temperature reduction composition metal ball Group；

Step 6, the cooling of high temperature reduction composition metal pellet and sorting, by the high temperature reduction composition metal of step 5 gained Pellet anaerobic is carried out magnetic material and is sorted with non-magnetic material after being cooled to room temperature, obtain degree of metalization and be more than 90%, pressure resistance Degree is more than the high-intensity composite metal pellet product of 1600N/ ball.

6. the production work of the high-intensity composite metal pellet that utilization iron containing metallurgical dust according to claim 5 produces Skill it is characterised in that：When described composition metal pellet is in reduction roasting using joining reducing agent outward, described step can be omitted Rapid three, the grade according to iron ore concentrate during the reduction roasting of described step 5 composition metal pellet, allocate institute into reduction kiln is also interior State the reduction coal of composition metal pellet quality 15～20%.

7. the production work of the high-intensity composite metal pellet that utilization iron containing metallurgical dust according to claim 5 produces Skill it is characterised in that：Described reduction kiln is tunnel cave or car-bottom furnace or batch-type furnace.