CN1236815A - Quick reduction process for cold solidified spheroids of iron concentrate in rotary kiln - Google Patents
Quick reduction process for cold solidified spheroids of iron concentrate in rotary kiln Download PDFInfo
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- CN1236815A CN1236815A CN 99115347 CN99115347A CN1236815A CN 1236815 A CN1236815 A CN 1236815A CN 99115347 CN99115347 CN 99115347 CN 99115347 A CN99115347 A CN 99115347A CN 1236815 A CN1236815 A CN 1236815A
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Abstract
A process for quickly reducin the cold-solidified spheroids of iron ore concentrate in rotary kiln includes preparing cold-solidified spheroids, full-kiln high-temp reduction, and using high-temp tail gas to burn boiler to generate steam for electric generation. Its advantages include solving the problems that the compound adhesive for spheroids can easily bind the raw material together and blockthe flow way during grinding, fully playing the role of adhesive for forming spheroids by rolling and automatic classification, saving investment by 30%, high TFe greater than 90% and iron recovery rate higher than 91%, low energy consumption and saving reduction cost by about 15%.
Description
The invention relates to a direct reduction process of an iron concentrate rotary kiln, in particular to a rapid reduction process of an iron concentrate cold-bonded pellet coal-based rotary kiln, belonging to a non-blast furnace iron-making technology.
Direct reduction of iron ore is one of the leading issues important in the field of ferrous metallurgy. According to the characteristics of resources and energy in China, the direct reduction process of the iron ore pellet rotary kiln using coal as a reducing agent is suitable for being developed in China. The direct reduction process of the iron ore pellets in the rotary kiln can be divided into an oxidized pellet reduction method, a preheated pellet reduction method and a cold-bonded pellet reduction method according to the preparation method of the iron ore pellets entering the reduction kiln. The oxidation pellet reduction method is characterized in that iron ore concentrate green pellets are solidified at a high temperature of 1200-1250 ℃ and then reduced, the preheating pellet reduction method is characterized in that green pellets with iron ore concentrate added with a binder are preheated at a temperature of 850-900 ℃ and then reduced, the cold-solidified pellet method (Chinese patent CN92111782.5) is characterized in that iron ore concentrate added with a composite binder is made into green pellets, and the green pellets are dried, dehydrated and solidified at a temperature of 200-250 ℃ and then reduced. The heat generated by the three methods during high-temperature reduction is not effectively and reasonably utilized; the former two methods have long reduction time, low kiln utilization coefficient and high production cost, so that the direct reduction process of the rotary kiln has low benefit and poor market competitiveness of products. The cold-bonded pelletizing method also has some defects, the iron ore concentrate added with the composite binder is difficult to pelletize, and the material discharge of an edge runner mill is not smooth; unreasonable reduction temperature field of the rotary kiln, low utilization degree of high-temperature waste gas heat at the tail of the rotary kiln and the like.
The invention aims to solve the problems of high energy consumption, low heat energy utilization rate and low production efficiency in the process of converting the direct reduction process of the iron concentrate cold-bonded pellet coal-based rotary kiln into the productivity so as to ensure smooth production flow.
The method comprises the steps of preparing cold-bonded pellets, reducing the pellets in the whole kiln at high temperature, and generating power by using the high-temperature waste gas at the tail of the rotary kiln.
Preparing cold-bonded pellets: the method comprises the steps of fully mixing 1-2% of a composite binder and 85% of iron ore concentrate with the fineness of-0.076 mm in percentage by weight in a strong mixer or a wet mill, pelletizing the uniformly mixed iron ore concentrate in a disc pelletizer, wherein the diameter of the pellets is 10-16 mm, drying and solidifying the green pellets in a belt dryer at the drying temperature of 150-250 ℃, adjusting the temperature to 150-250 ℃ after adding cold air into kiln tail waste gas at the heat source utilization temperature of 900-1000 ℃, and feeding the green pellets into the dryer. The adopted composite binder contains 90-96% of solid sodium humate and 4-10% of slaked lime. Aiming at the problems of high material viscosity, failure of automatic grading of material balls and incapability of normal and stable pelletizing of the material balls containing the composite binder, a scraper is added on a ball disc of a disc pelletizer to realize rolling pelletizing and automatic grading, stable pelletizing and subsequent processes. The spherical disc of the disc pelletizer comprises scrapers 1, 2 and 3, wherein the scraper 1 is located on the radius of the spherical disc, the central connecting line of the contact points of the scraper 2 and the edge of the spherical disc forms an angle of 135 degrees with the scraper 1, the central connecting line of the contact points of the scraper 3 and the edge of the spherical disc forms an angle of 30-45 degrees with the reverse extension line of the scraper 1, and the central connecting line of the contact points of the scraper 3 and the edge of the spherical disc forms an angle of 5-10 degrees.
And (3) full-kiln high-temperature rapid reduction: the reduction temperature is 1000-1050 ℃, and two rods are additionally arranged at the head of the kilnThe coal-spraying gun and the embedded burner at the tail of kiln are matched with primary air and secondary airThe requirement of a high-temperature field of the whole kiln is met; the coal is not added at the tail of the kiln, the coal throwing amount at the head of the kiln is increased, and the coal throwing time is shortened The reduced low-strength interval reduces the powder generation amount and avoids the ring formation of the rotary kiln. The utilization coefficient of the rotary kiln can be improved to 0.4-0.5T/m3·d。
Generating power by waste heat: the invention designs a waste heat power generation workshop for building a plant, most of the high-temperature waste gas is used for a combustion boiler to produce steam for power generation, the annual power generation amount reaches 3000kw, the annual power consumption is more than that of a direct reduction iron plant, and the heat energy of the high-temperature waste gas is fully utilized.
Description of the drawings:
FIG. 1: the invention uses the schematic diagram of the installation position of the spherical pan scraper of the disc pelletizer.
The invention has the advantages that:
① the invention adopts a strong mixer or a wet mill to replace a roller mill, solves the problems ofmaterial sticking and blocking of fine iron ore concentrate containing composite binder in mixing and milling, successfully solves the problems of smooth flow and full play of binder effect, has dry ball strength of 250-400N/piece and abrasion resistance index (less than 3 mm) less than 3%, can completely meet the requirement of rotary kiln reduction, has the problems of large material viscosity, automatic classification failure of material balls and incapability of normal stable pelletizing of the material balls aiming at the composite binder on a disc pelletizer ②, adopts forced classification technology (adding a scraper on a ball disc), realizes rolling pelletizing and automatic classification, stabilizes pelletizing and subsequent processes, has ③ adopts a belt machine made of common steel for drying and consolidation, saves investment, reduces construction investment by 30%, reduces energy consumption by 20%, improves kiln utilization coefficient by 10-20% by ④ adopting full-kiln high-temperature rapid reduction technology, and shortens the use ratio by 10-20% by adopting full kiln high-temperature rapid reduction technology The reduced low-strength interval enlarges the production capacity, reduces the powder output and avoids the ring formation of the rotary kiln.⑤ the method for generating electricity by waste heat of high-temperature waste gas at kiln tail of rotary kiln is used to realize self-supply and surplus of electricity, so that it can fully and effectively utilize energy, reduce production cost and obviously raise comprehensive economic benefit of new process, and the DRI TFe products produced by said invention are greater than 90%, ηFeMore than 93 percent, the iron recovery rate is more than 91.0 percent, the energy consumption is 708kg standard coal/t.DRI, the production cost is 896/t.DRI, and the unit direct reduced iron cost is reduced by about 15 percent.
Example (b): the Shandong Luzhong metallurgy mine company adopts a new technology of direct reduction of iron ore concentrate cold-bonded pellet coal-based rotary kilns to build a pellet mill producing 5 million tDRI annually. The method comprises the steps of fully mixing 2% of composite binder and 85% of iron ore concentrate with the fineness of-0.076 mm in a powerful mixer, pelletizing the uniformly mixed iron ore concentrate in a disk pelletizer with a scraper on a pellet disc (the diameter of the pellet is 10-16 mm), drying and solidifying the green pellets in a belt dryer at the drying temperature of 250 ℃ and the heat source of part of kiln tail high-temperature waste gas (900-1000 ℃), adjusting the temperature to 250 ℃ after adding cold air, and then feeding the green pellets into the dryer. After pelletizing, the reduction temperature is 1050 ℃, coal is not added at the tail of the kiln, the coal throwing amount at the head of the kiln is increased, and the utilization coefficient of the rotary kiln is 0.5T/m3Production of the product DRITFe>90%, ηFeMore than 93 percent, the iron recovery rate is more than 91.0 percent, the energy consumption is 708kg standard coal/t.DRI, the production cost is 896 yuan/t.DRI, and the cost of unit direct reduced iron is reduced by about 15 percent.
Claims (4)
1. The invention relates to a new process for reducing iron ore concentrate cold-bonded pellets in a rotary kiln, which comprises the steps of preparing cold-bonded pellets and reducing the cold-bonded pellets in a whole kiln at high temperature, and is characterized in that: the method comprises the steps of fully mixing 1-2% of composite binder and 85% of iron ore concentrate with the fineness of-0.076 mm in percentage by weight in a powerful mixer or a wet mill, pelletizing the uniformly mixed iron ore concentrate in a disc pelletizer, wherein the diameter of the pellets is 10-16 mm, drying and solidifying the green pellets in a belt dryer at the drying temperature of 150-250 ℃, and rapidly reducing the green pellets in a whole kiln at the high temperature of 1000-1050 ℃.
2. An apparatus for implementing the method of claim 1, wherein: a scraper is installed on a spherical disc of the disc pelletizer, the scraper 1 is located on the radius of the spherical disc, a 135-degree angle is formed between the center connecting line of the contact point of the scraper 2 and the edge of the spherical disc and the scraper 1, a 30-45-degree angle is formed between the center connecting line of the contact point of the scraper 3 and the edge of the spherical disc and the reverse extension line of the scraper 1, and a 5-10-degree angle is formed between the center connecting line of the contact point of the scraper 3 and the edge of the spherical disc.
3. An apparatus for implementing the method of claim 1, wherein: two coal-spraying guns and embedded burners at the tail of the kiln are additionally arranged at the head of the rotary kiln and are matched with primary air and secondary air for adjustment so as to meet the requirement of a high-temperature field of the whole kiln.
4. The method of claim 1, wherein: the high-temperature waste gas at the tail of the kiln is used for burning a boiler to produce steam for power generation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99115347A CN1070535C (en) | 1999-04-30 | 1999-04-30 | Quick reduction process for cold solidified spheroids of iron concentrate in rotary kiln |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99115347A CN1070535C (en) | 1999-04-30 | 1999-04-30 | Quick reduction process for cold solidified spheroids of iron concentrate in rotary kiln |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1236815A true CN1236815A (en) | 1999-12-01 |
| CN1070535C CN1070535C (en) | 2001-09-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN99115347A Expired - Fee Related CN1070535C (en) | 1999-04-30 | 1999-04-30 | Quick reduction process for cold solidified spheroids of iron concentrate in rotary kiln |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1319684C (en) * | 2005-04-25 | 2007-06-06 | 昆明理工大学 | Method for preparing natural micro alloy iron powder from vanadium-titanium-iron headings by microwave radiation |
| CN102642027A (en) * | 2012-04-11 | 2012-08-22 | 莱芜钢铁集团有限公司 | Process for producing reduced iron powder |
| CN102747221A (en) * | 2012-06-14 | 2012-10-24 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Method for making cold-pressed balls through using powdery material containing iron |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5685893A (en) * | 1991-08-02 | 1997-11-11 | Allied Colloids Limited | Ore pelletization |
| CN1035196C (en) * | 1992-12-23 | 1997-06-18 | 中南工业大学 | Direct reduction technology for compound adhesive cool solidifying globus coal base |
-
1999
- 1999-04-30 CN CN99115347A patent/CN1070535C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1319684C (en) * | 2005-04-25 | 2007-06-06 | 昆明理工大学 | Method for preparing natural micro alloy iron powder from vanadium-titanium-iron headings by microwave radiation |
| CN102642027A (en) * | 2012-04-11 | 2012-08-22 | 莱芜钢铁集团有限公司 | Process for producing reduced iron powder |
| CN102642027B (en) * | 2012-04-11 | 2014-01-15 | 莱芜钢铁集团有限公司 | Process for producing reduced iron powder |
| CN102747221A (en) * | 2012-06-14 | 2012-10-24 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Method for making cold-pressed balls through using powdery material containing iron |
| CN102747221B (en) * | 2012-06-14 | 2016-10-05 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Make the method for cold-pressing balls of iron content granular material |
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| Publication number | Publication date |
|---|---|
| CN1070535C (en) | 2001-09-05 |
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