CN112280974B - Method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals - Google Patents

Method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals Download PDF

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CN112280974B
CN112280974B CN202011251271.6A CN202011251271A CN112280974B CN 112280974 B CN112280974 B CN 112280974B CN 202011251271 A CN202011251271 A CN 202011251271A CN 112280974 B CN112280974 B CN 112280974B
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iron
tail gas
balls
cement clinker
containing minerals
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CN112280974A (en
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李玉杰
林元钟
王懿实
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Fujian Xinze Trading Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/242—Binding; Briquetting ; Granulating with binders
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/02—Portland cement
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/14—Cements containing slag
    • C04B7/147—Metallurgical slag
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/36—Manufacture of hydraulic cements in general
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/2406—Binding; Briquetting ; Granulating pelletizing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

Abstract

The invention discloses a method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals, which comprises the steps of adding brown coal powder, NHC, calcium carbonate and a binder into the refractory iron-containing minerals, preparing balls, drying, dehydrating, carrying out deep reduction, cooling cooked balls, carrying out ball milling, feeding the generated ore pulp into a magnetic separation system, sorting by a magnetic separator to obtain reduced iron powder with the total iron content of more than 92% and the metallization rate of more than 93%, briquetting and forming the iron powder for electric furnace steelmaking, allowing harmful substances to form silicates through high-temperature chemical reaction to enter tailings, allowing the tailings to be used as portland cement accessories, allowing the reduced tail gas to be used as heat energy of the drying system, cooling the tail gas by stages, collecting dust, purifying the tail gas, and carrying out compression separation treatment, returning the reduced gas to be reused, introducing the purified gas reaching the standard into water to form calcium salts such as calcium carbonate and calcium sulfide, fishing out and mixing into the iron-removed tailings to be used as portland cement clinker.

Description

Method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals
Technical Field
The invention belongs to the field of comprehensive utilization of low-grade iron-containing mineral, and particularly relates to a method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing mineral.
Background
The iron-containing mineral refers to a material which is produced in the smelting process and contains more than 15% of iron, 1.0-3.0% of sulfur and less than 0.1% of heavy metals (such as arsenic and antimony). Iron slag is widely derived from non-ferrous metal smelting processes. For example, the hydrometallurgical process of gold, the pyrometallurgical process of copper, the process of preparing sulfuric acid by the pyrometallurgical process in sulfuric acid plants, and the process of extracting sulfur by the pyrometallurgical process all produce iron-containing slag in large quantities. The total iron content of the sulfur slag accounts for 18% -27% of the slag content, the total iron content of the sulfuric acid slag is highest, and the total iron content can account for 50% -62% of the slag content, because the raw materials for preparing the sulfuric acid are sulfur iron minerals with higher purity obtained after flotation, and after the sulfur element is extracted by a pyrogenic process, iron is enriched and left in the tailings. The total iron content of iron slag generated in the pyrometallurgical process of copper slag generally accounts for about 40% of slag, lean ore resources in China are rich, but most iron ore cannot be enriched and belongs to refractory ore dressing, such as limonite and hematite, the total iron content generally does not exceed 50%, the iron slag cannot be directly used as an iron-making raw material, a common ore dressing method is difficult to enrich, and the iron slag cannot be utilized in the iron and steel industry for a long time.
30 billion gold smelting plants, sulfuric acid plants, sulfur plants, copper smelting plants and the like in China need to produce 30 billion iron smelting slag every year, the future 2 to 3 years are forecasted in the industry, the industrial solid waste tailings exceed more than 40 billion tons, the iron-containing smelting slag accumulated in the past exceeds 10 billion tons, and if the iron-containing smelting slag is stored outdoors for a long time and is not recycled, the resource waste and the environmental pollution are caused. Therefore, the comprehensive utilization of the iron slag has important economic and environmental benefits.
Disclosure of Invention
The invention aims to provide a method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals, which aims at producing iron-containing slag and refractory ores (limonite and hematite) which cannot be enriched in iron mines in China in the non-ferrous metal smelting process, and provides a method for treating iron-containing substances to realize slag-iron separation, wherein harmful substances enter tailings, the iron-containing minerals are enriched to become a high-quality steel raw material, namely reduced iron (sponge iron), the total iron content of the iron reaches more than 92%, and other harmful substances such as antimony, bismuth and the like are also reduced to less than 0.0003%, so that the requirements of the high-quality steel production raw materials are completely met. The method realizes the production of high-quality steel raw materials from non-ferrous metal smelting slag and low-grade ores, and simultaneously, tailings generated by slag-iron separation are directly used for silicate cement batching, so that the harmless treatment of industrial solid waste tailings is realized, and greater economic benefit is generated.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals comprises the following steps:
1) Grinding refractory iron-containing minerals, adding 14-16 wt% of lignite, 1.4-1.6 wt% of iron ion aggregating agent (NHC), 1.4-1.6 wt% of calcium carbonate (desulfurization) and 1.4-1.6 wt% of adhesive C6H1005 (simultaneously having reduction effect), mixing the materials uniformly by a mixer, and making into a ball forming machine to obtain a mixed ball with a ball diameter of 2-3 cm;
2) Feeding the mixed balls into a dryer by using a stripe belt, and drying and preheating by using the waste heat of tail gas to obtain hot balls;
3) The hot pellets are sent into an improved reduction shaft furnace through a grate chain machine, the temperature is set to be 1000-1100 ℃, the time is 1.5-2 hours, and the metallized pellets are generated by reduction;
4) The metallized pellets enter a cold water circulating pool through vibration discharging equipment to be rapidly cooled to obtain cold pellets;
5) The cold balls are pulled out of the cold water circulating pool by a slag pulling machine, are fed into a ball mill through a feeding machine, are added with water for ball milling, and are subjected to adjustment on the concentration of ore pulp to be 30-33% after ball milling, wherein the concentration of the ore pulp is = the mass of the material/(the mass of the material + the water) × 100%);
6) The ore pulp is subjected to first magnetic separation, magnetic substances enter demagnetizing equipment to eliminate magnetic agglomeration, and iron-containing substances are subjected to second magnetic separation again to select reduced iron powder with the total iron content of more than 92% and the metallization rate of more than 93%;
7) The iron powder enters a disc type filter for dehydration, and is sent into a briquetting machine by a feeder after dehydration for forming and briquetting to form reduced iron blocks;
the reason for briquetting is as follows: because the iron powder contains more than 92 percent of iron, the metallization rate is high, secondary oxidation is very easy if briquetting treatment is not carried out, the iron grade is reduced, the product quality is influenced, and the storage and the transportation are not easy;
8) All tailings enter a thickening tank after passing through an iron recovery device, pass through a thickening device and then enter a vacuum belt filter for dehydration, and the dehydrated materials are sent to a cement plant to be used as cement clinker;
9) Wastewater generated by iron powder dehydration and tailing dehydration flows into a reservoir through a pipeline for clarification and recycling, and can be used as water for ball mill size mixing, namely medium water;
10 In the process of the present invention, a reduction tail gas is generated, specifically as follows:
reduction tail gas 3CO (gas) + Fe 2 O 3 ==2Fe + 3CO 2 (gas) is added into the mixture to be stirred,
4 FeS 2 +11O 2 (gas) = =8SO 2 (Minicous) +2Fe 2 O 3
The temperature of the generated reduction tail gas (carbon dioxide, excessive carbon monoxide, minimal sulfur dioxide and dust) reaches 800 ℃, and the reduction tail gas is sent into a heat-insulating pipeline through an exhaust port and led to a dryer to be used as a heat source;
11 Final tail gas temperature is about 300 ℃, and dust removal and purification are carried out by three-stage dust removal (bag dust collection, cyclone dust collection and spray dust removal) equipment;
12 The tail gas after dust removal and purification is compressed and separated, the carbon monoxide gas with reducibility is returned to reduction equipment for reuse, and the carbon dioxide and the sulfur-containing gas (the purified gas is almost the carbon dioxide) are introduced into a lime water pool and react with lime water (CO) 2 +Ca(OH) 2 =CaCO 3 +H 2 O，SO 2 +Ca(OH) 2 =CaSO 3 ↓+H 2 O) forming calcium carbonate, calcium sulfite and the like, fishing out, drying and mixing into tailings to be used as cement clinker;
13 Water vapor generated by the cold water circulating tank is led into cold water, and clear water is formed by condensation and then is used as ore concentrate washing water.
Further, in the step 1), the granularity of the grinded refractory iron-containing minerals is 0.07-0.08mm, and the refractory iron-containing minerals with the granularity accounts for more than 60% of the grinded refractory iron-containing minerals.
In the step 1), the refractory iron-containing minerals are one or more of limonite, hematite, pyrometallurgical copper slag, sulfur extraction slag, sulfuric acid slag or gold cyanidation slag containing iron more than 15%.
In the step 6), the magnetic field intensity of the first magnetic separation is 0.24-0.25T, and the magnetic field intensity of the second magnetic separation is 0.13-0.14T.
The invention adopts the technical scheme, in order to realize the maximum benefit of the product, the invention mixes the iron-containing mineral after fine grinding into brown coal, NHC (iron ion aggregating agent), calcium carbonate (desulfurizer), mixture C6H1005 (simultaneously playing a reducing role), the mixture is made into balls by using a disk pelletizer, the balls are sent into an improved reduction shaft furnace for deep reduction after being dried, dehydrated and preheated, cooked balls are sent into a circulating water tank for quick cooling through vibration discharging equipment to prevent secondary oxidation, cold balls are pulled into a ball mill by a slag pulling machine to carry out fine grinding (water is used as a medium), ore pulp generated after ball grinding is graded by a spiral classifier, unqualified materials are returned to the ball mill for ball grinding again, qualified granularity materials are sent into a magnetic separation system for selection, reduced iron powder with the total iron content of more than 92 percent and the metallization rate of more than 93 percent can be obtained under the conditions of 0.24-0.25T of magnetic field strength and 0.13-0.14T of magnetic field strength, the iron powder is formed by briquetting and used for steelmaking, the heavy metal content is trace, harmful substances also can be used for forming silicate cement clinker under the conditions of high temperature chemical reaction to form tailings, and the silicate clinker meets the requirements of silicate cement clinker under the high temperature. The temperature of the residual heat of the deep reduction tail gas discharged from the furnace is about 800 ℃, the tail gas is introduced into the preheating drying furnace through a heat insulation pipeline to be used as a heat source, so that the heat energy is fully utilized, the secondary tail gas treatment process is reduced, the heat energy utilization rate is increased by 15-20%, and the cost is reduced.
The invention has the advantages that: (1) The problem that blast furnace iron making cannot be carried out by using iron-containing metallurgical tailings and low-grade refractory ores is solved, so that waste which cannot be recycled in the past is completely utilized, and waste is changed into valuable; the dilemma of resource shortage of high-quality special steel is solved; the problem of environmental pollution caused by stacking of waste is solved; the problem that low-grade mines cannot be developed and utilized is solved; the dependence of the reduced iron on import is relieved. (2) Compared with the method for directly reducing high-grade iron ore, the method saves 90 percent of the cost of raw materials. For example, the raw material cost of sponge iron produced by directly reducing iron concentrate powder containing more than 67% of iron is 1200 yuan/ton, and if sponge iron is produced by using low-grade iron-containing substances, the raw material cost is only 100 yuan/ton (limonite and hematite), and the cost of other metallurgical waste residues is almost negligible. In the aspect of energy consumption, because the fine iron powder basically belongs to magnetite, most of slag and limonite hematite belong to the category of ferric oxide, the reduction difficulty of the magnetite is far greater than that of the ferric oxide, and the specific heat capacity is also smaller than that of the magnetite, so the energy consumption is lower. But because the iron-containing grade is low, the selection ratio is low, the energy consumption of the iron-containing grade and the selection ratio is relatively small, the energy consumption of the iron-containing grade and the selection ratio is relatively different from that of the iron-containing grade and the selection ratio through comprehensive calculation and test, the product cost is reduced by 80%, the profit is far larger than that of the direct reduced iron produced by high-grade iron ore (powder), the raw material sources are very wide, and the direct reduced iron produced by high-grade iron ore is not bound by the extremely high requirements of the raw materials. The reduced iron produced by the method has the total iron content and the metallization rate far exceeding that of imported sponge iron (the total iron grade of reduced iron blocks imported by Ira is 91.72 percent, and the metallization rate is 80.3 percent). (3) The product produced by the invention has the total iron content of more than 92 percent, the metallization rate of more than 93 percent, the steelmaking harmful substances such as sulfur, phosphorus, arsenic, antimony, bismuth and the like of less than 0.0003 percent and the silicon dioxide of less than 2 percent. (4) The invention has the advantages of reasonable design, tight system, almost no exhaust gas, and valuable utilization of tailings. The invention changes all the previously unavailable and unavailable ores, such as low-grade limonite and low-grade hematite (including secondary pollution slag, such as copper-smelting tailings, sulfur slag, cyaniding slag, aluminum slag and the like), into valuable substances, has considerable benefits, is pollution-free, environment-friendly and belongs to clean utilization.
Detailed Description
Example 1
A method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals comprises the following steps:
1) Grinding refractory iron-containing minerals (limonite containing more than 15% of iron) to the granularity of about 0.074mm, adding 15% of lignite, 1.5% of iron ion aggregating agent (NHC), 1.5% of calcium carbonate and 1.5% of adhesive C6H1005 (having a reducing effect at the same time) by weight, uniformly mixing the materials by a mixer, and making into a ball forming machine to prepare a mixed ball with the ball diameter of 2-3 cm;
2) Feeding the mixed balls into a dryer by using a stripe belt, and drying and preheating by using the waste heat of tail gas to obtain hot balls;
3) The hot pellets are sent into an improved reduction shaft furnace through a grate chain machine, the temperature is set to 1050 ℃, the time is 1.5 hours, and the metallized pellets are produced by reduction;
4) The metallized pellets enter a cold water circulating pool through vibration discharging equipment to be rapidly cooled to obtain cold pellets;
5) A slag drawing machine for cold balls is used for drawing the cold balls out of the cold water circulating pool, the cold balls are conveyed into a ball mill through a feeding machine, water is added for ball milling, and the concentration of ore pulp is adjusted to 31.53 percent after ball milling;
6) The ore pulp is subjected to first magnetic separation (the magnetic field intensity is 0.24T), magnetic substances enter demagnetizing equipment to eliminate magnetic agglomeration, and iron-containing substances are subjected to second magnetic separation (the magnetic field intensity is 0.13T) again to select reduced iron powder with the total iron content of more than 92 percent and the metallization rate of more than 93 percent;
7) The iron powder enters a disc filter for dehydration, and is sent into a briquetting machine by a feeder after dehydration to be molded and briquetted (the diameter is 10 cm, the height is 10 cm) to become reduced iron blocks;
8) All tailings enter a thickening tank after passing through an iron recovery device, pass through a thickening device and then enter a vacuum belt filter for dehydration, and the dehydrated materials are sent to a cement plant to be used as cement clinker;
9) Wastewater generated by iron powder dehydration and tailing dehydration flows into a reservoir through a pipeline for clarification and cyclic utilization;
10 In the above steps, reducing tail gas is generated, the temperature of the reducing tail gas (carbon dioxide, excessive carbon monoxide, minimal sulfur dioxide and dust) is up to 800 ℃, and the reducing tail gas is sent into a heat preservation pipeline through an exhaust port and led to a dryer to be used as a heat source;
11 Final tail gas temperature is about 300 ℃, and dust removal and purification are carried out by three-stage dust removal (bag dust collection, cyclone dust collection and spray dust removal) equipment;
12 The tail gas after dust removal and purification is compressed and separated, the carbon monoxide gas with reducibility is returned to reduction equipment for reuse, and the carbon dioxide and the sulfur-containing gas (the purified gas is almost the carbon dioxide) are introduced into a lime water pool and react with lime water (CO) 2 +Ca(OH) 2 =CaCO 3 +H 2 O，SO 2 +Ca(OH) 2 =CaSO 3 ↓+H 2 O) forming calcium carbonate, calcium sulfite and the like, fishing out, drying and mixing into tailings to be used as cement clinker;
13 Water vapor generated by the cold water circulating tank is led into cold water, and clear water is formed by condensation and then is used as ore concentrate washing water.
Example 2
A method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals comprises the following steps:
1) Grinding refractory iron-containing minerals (hematite containing more than 15% of iron) to the granularity of about 0.074mm, adding lignite accounting for 14% of the weight of the refractory iron-containing minerals, NHC accounting for 1.4% of the weight of the refractory iron-containing minerals, calcium carbonate (for desulfurization) accounting for 1.6% of the weight of the refractory iron-containing minerals and C6H1005 accounting for 1.6% of the weight of the refractory iron-containing minerals, uniformly mixing the materials by a mixer, feeding the materials into a pelletizer, and making the materials into a mixed ball with the ball diameter of 2-3 cm;
2) Feeding the mixed balls into a dryer by using a stripe belt, and drying and preheating by using the waste heat of tail gas to obtain hot balls;
3) The hot pellets are sent into an improved reduction shaft furnace through a grate chain machine, the temperature is set to be 1000 ℃, the time is 2 hours, and metallized pellets are generated through reduction;
4) The metallized pellets enter a cold water circulating pool through vibration discharging equipment to be rapidly cooled to obtain cold pellets;
5) The cold balls are pulled out from the cold water circulating pool by a slag pulling machine, are sent into a ball mill through a feeding machine, are added with water for ball milling, and the concentration of ore pulp is adjusted to be 30 percent after ball milling;
6) The ore pulp is subjected to first magnetic separation (the magnetic field intensity is 0.25T), magnetic substances enter demagnetizing equipment to eliminate magnetic agglomeration, and iron-containing substances are subjected to second magnetic separation (the magnetic field intensity is 0.14T) again to select reduced iron powder with the total iron content of more than 92 percent and the metallization rate of more than 93 percent;
7) The iron powder enters a disc filter for dehydration, and is sent into a briquetting machine by a feeder after dehydration to be molded and briquetted (the diameter is 10 cm, the height is 10 cm) to become reduced iron blocks;
the reason for briquetting is as follows: because the iron content of the iron powder is more than 92 percent, the metallization rate is high, secondary oxidation is easy to occur if briquetting treatment is not carried out, the iron grade is reduced, the product quality is influenced, and the iron powder is not easy to store and transport;
8) All tailings enter a thickening tank after passing through iron recovery equipment, pass through thickening equipment and then enter a vacuum belt filter for dehydration, and the dehydrated materials are sent to a cement plant to serve as cement clinker;
9) Wastewater generated by iron powder dehydration and tailing dehydration flows into a reservoir through a pipeline to be clarified and recycled;
10 In the above step, the reduction tail gas 3CO (gas) + Fe is produced 2 O 3 ==2Fe + 3CO 2 (gas) is added into the mixture,
4 FeS 2 +11O 2 (gas) = =8SO 2 (Minicous) +2Fe 2 O 3
Reducing tail gas (carbon dioxide, excessive carbon monoxide, minimal sulfur dioxide and dust) with the temperature of 800 ℃, sending the temperature to a heat-insulating pipeline through an exhaust port, and leading the temperature to a dryer to be used as a heat source;
11 The final tail gas temperature is about 300 ℃, and dust removal and purification are carried out by three-stage dust removal (bag dust collection, cyclone dust collection and spray dust removal) equipment;
12 The tail gas after dust removal and purification is compressed and separated, the carbon monoxide gas with reducibility is returned to reduction equipment for reuse, and the carbon dioxide and the sulfur-containing gas (the purified gas is almost the carbon dioxide) are introduced into a lime water pool and react with lime water (CO) 2 +Ca(OH) 2 =CaCO 3 +H 2 O，SO 2 +Ca(OH) 2 =CaSO 3 ↓+H 2 O) forming calcium carbonate, calcium sulfite and the like, fishing out, drying and mixing into tailings to be used as cement clinker;
13 Water vapor generated by the cold water circulating tank is led into the cold water, and clear water is formed by condensation and then is used as ore concentrate washing water.
Example 3
A method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals comprises the following steps:
1) Grinding refractory iron-containing minerals, adding 16 wt% of lignite, 1.6 wt% of iron ion aggregating agent (NHC), 1.6 wt% of calcium carbonate (desulfurization) and 11.6 wt% of adhesive C6H1005 (simultaneously having a reducing effect), uniformly mixing the materials by a mixer, and making into a ball forming machine to obtain a mixed ball with a ball diameter of 3 cm;
the refractory iron-containing mineral is a mixture of pyrometallurgical copper slag, sulfur extraction slag and sulfuric acid slag;
2) Feeding the mixed balls into a dryer by using a stripe belt, and drying and preheating by using the waste heat of tail gas to obtain hot balls;
3) The hot pellets are sent into an improved reduction shaft furnace through a grate chain machine, the temperature is set to be 1100 ℃, the time is 1.5 hours, and the metallized pellets are generated through reduction;
4) The metallized pellets enter a cold water circulating pool through vibration discharging equipment to be rapidly cooled to obtain cold pellets;
5) A slag drawing machine for cold balls is used for drawing the cold balls out of the cold water circulating pool, the cold balls are conveyed into a ball mill through a feeding machine, water is added for ball milling, and the concentration of ore pulp is adjusted to 33% after ball milling;
6) The ore pulp is subjected to first magnetic separation (the magnetic field intensity is 0.24T), magnetic substances enter demagnetizing equipment to eliminate magnetic agglomeration, and iron-containing substances are subjected to second magnetic separation (the magnetic field intensity is 0.14T) again to select reduced iron powder with the total iron content of more than 92 percent and the metallization rate of more than 93 percent;
7) The iron powder enters a disc filter for dehydration, and is sent into a briquetting machine by a feeder after dehydration to be molded and briquetted (the diameter is 10 cm, the height is 10 cm) to become reduced iron blocks;
8) All tailings enter a thickening tank after passing through an iron recovery device, pass through a thickening device and then enter a vacuum belt filter for dehydration, and the dehydrated materials are sent to a cement plant to be used as cement clinker;
9) Wastewater generated by iron powder dehydration and tailing dehydration flows into a reservoir through a pipeline to be clarified and recycled (the wastewater is used as water for ball mill size mixing and is also called medium water);
10 In the above step, the reduction tail gas 3CO (gas) + Fe is produced 2 O 3 ==2Fe + 3CO 2 (gas) is added into the mixture to be stirred,
4 FeS 2 +11O 2 (gas) = =8SO 2 (Minicous) +2Fe 2 O 3
Reducing tail gas (carbon dioxide, excessive carbon monoxide, minimal sulfur dioxide and dust) with the temperature of 800 ℃, sending the temperature to a heat-insulating pipeline through an exhaust port, and leading the temperature to a dryer to be used as a heat source;
11 Final tail gas temperature is about 300 ℃, and dust removal and purification are carried out by three-stage dust removal (bag dust collection, cyclone dust collection and spray dust removal) equipment;
12 Compressing and separating the tail gas after dust removal and purification, returning the reducing carbon monoxide gas to reduction equipment for reuse, introducing carbon dioxide and sulfur-containing gas (the purified gas is almost carbon dioxide) into a lime water pool, and reacting with lime water (CO) 2 +Ca(OH) 2 =CaCO 3 +H 2 O，SO 2 +Ca(OH) 2 =CaSO 3 ↓+H 2 O) forming calcium carbonate, calcium sulfite and the like, fishing out, drying and mixing into tailings to be used as cement clinker;
13 Water vapor generated by the cold water circulating tank is led into cold water, and clear water is formed by condensation and then is used as ore concentrate washing water.

Claims (1)

1. A method for producing reduced iron and portland cement clinker by using low-grade refractory iron-containing minerals is characterized by comprising the following steps: the method comprises the following steps:
1) Grinding refractory iron-containing minerals to the granularity of 0.074mm, wherein the refractory iron-containing minerals are limonite containing more than 15% of iron, adding lignite accounting for 15% of the weight of the refractory iron-containing minerals, 1.5% of an iron ion aggregating agent, 1.5% of calcium carbonate and 1.5% of an adhesive, uniformly mixing the materials by a mixer, and making the mixture into a mixing ball with the ball diameter of 2-3cm by a pelletizer; the iron ion aggregating agent is NHC, and the adhesive is C6H1005;
2) Feeding the mixed balls into a dryer by using a stripe belt, and drying and preheating by using the waste heat of tail gas to obtain hot balls;
3) The hot pellets are sent into an improved reduction shaft furnace through a grate conveyor, the temperature is set to 1050 ℃, the time is 1.5 hours, and metallized pellets are generated through reduction;
4) The metallized pellets enter a cold water circulating pool through vibration discharging equipment to be rapidly cooled to obtain cold pellets;
5) A slag drawing machine for cold balls is used for drawing the cold balls out of the cold water circulating pool, the cold balls are conveyed into a ball mill through a feeding machine, water is added for ball milling, and the concentration of ore pulp is adjusted to 31.53 percent after ball milling;
6) The ore pulp is subjected to first magnetic separation, magnetic substances enter demagnetizing equipment to eliminate magnetic agglomeration, iron-containing substances are subjected to second magnetic separation again to select reduced iron powder with the total iron content of more than 92 percent and the metallization rate of more than 93 percent, the harmful substances of sulfur, phosphorus, arsenic, antimony and bismuth in steelmaking are less than 0.0003 percent, and the silicon dioxide is less than 2 percent; the magnetic field intensity of the first magnetic separation is 0.24T, and the magnetic field intensity of the second magnetic separation is 0.13T;
7) The iron powder enters a disc type filter for dehydration, and is sent into a briquetting machine by a feeder after dehydration for forming and briquetting to form reduced iron blocks; the diameter of the pressing block is 10 cm, and the height of the pressing block is 10 cm;
8) All tailings enter a thickening tank after passing through iron recovery equipment, pass through thickening equipment and then enter a vacuum belt filter for dehydration, and the dehydrated materials are sent to a cement plant to serve as cement clinker;
9) Wastewater generated by iron powder dehydration and tailing dehydration flows into a reservoir through a pipeline to be clarified and recycled;
10 In the above steps, reducing tail gas is generated, the temperature of the reducing tail gas is up to 800 ℃, and the reducing tail gas is sent into a heat preservation pipeline through an exhaust port and led to a dryer to be used as a heat source;
11 The final tail gas temperature is about 300 ℃, and the dust is removed and purified by a three-stage dust removing device;
12 Compressing and separating the tail gas after dust removal and purification, returning carbon monoxide gas with reducibility to reduction equipment for reuse, introducing carbon dioxide and sulfur-containing gas into a lime water pool, reacting with lime water to form calcium carbonate and calcium sulfite, fishing out, drying and blending into tailings to serve as cement clinker;
13 Water vapor generated by the cold water circulating tank is led into the cold water, and clear water is formed by condensation and then is used as ore concentrate washing water.
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