A new generation of "green" steel production process

Construction of a new generation of "green" steel production process has been the target of contemporary steel industry, now the prototype process has been completed in South Africa Saldanha (Saldanha) steel plant and put into production in January 1999 was completed.

The Saldanha plant is located in the Gulf of Saldanha, South Africa. The plant is mainly made up of iron ore and coal . It has reached an annual output of 1.25 million tons of HRC, and plans to turn the annual output on this basis. Some time. The factory is currently the only one in the world that integrates a number of new steel production processes into one, namely, smelting reduction, direct reduction, electric furnace steelmaking, thin slab continuous casting, and forming a complete production line. Due to technical innovation, Saldanha steel plant significantly reducing investment costs and energy consumption technology, the plant with a total investment of $ 1.1 billion, the estimated annual gold exports amounted to $ 20 million. The plant's production index is 1.25 million tons of hot rolled coil per 2 million tons of iron ore, and the price per ton of finished steel is about 320 US dollars, which is competitive in the market. Using a new technology, it replaced the blast furnace-converter method steelmaking, forming a coke-free furnace, a blast-free friendly factory environment, and built a new generation of "green" steel plants.

The Saldanha steel mill has several technical features:

1. The industrial smelting reduction scheme that realizes the combination of smelting reduction and direct reduction adopts the Corex C2000 measuring device. The Corex method is the only industrialized method of smelting reduction method. As early as 1989, ISCO (ISCOR) company Biller The Pretoria plant has been completed and put into production with a 300,000-tonne Corex C1000 unit. It was improved. In 1995, the Corex C2000 unit was built by South Korea's Pohang Steel Company with an annual production capacity of 700,000 tons. Since then, including Saldanha, South Korea's Hanbao and India's JINDAL have plans to build the Corex C2000 unit. The Corex process produces a large amount of residual gas and consumes a lot of energy. If these gases are used effectively, energy and cost can be reduced. . After Salfsnhs purifies the large amount of residual gas CO ₂ produced by Corex C2000, the reducing gas used in the Midrex direct reduction iron method directly reduces iron ore to sponge iron. The pig iron produced by Corex and the direct reduced iron of Midrex are used as raw materials for electric steelmaking. The time is short, the harmful elements are few, the steelmaking efficiency is improved, and the clean production process of the coke-free furnace and the blast furnace is formed.

2. The factory adopts the new thin slab continuous casting process (the ISP process developed by Mannesmann Demark), which combines the rough rolling and continuous casting of the hot rolling mill, and casts a 90mm thin steel billet at one time, rough rolling to 20 ~30mm, further shortening the process, reducing investment and increasing labor productivity.

3, the entire process of the factory from the iron ore into the Corex or Midrex furnace operation to the final product release only 16h. All production processes are closely integrated, without any storage or buffering equipment in between, forming a continuous production line.

The specific production process of the Saldanha steelworks is as follows:

1. Iron ore and coal are sent directly from the Saldanha Bay to the factory via a 5km long conveyor belt.

2, Coreex C2000 direct melting plant produces liquid pig iron and by-products - reducing gases.

3. The factory purifies the gas to remove most of the CO ₂ in the Corex gas.

4. The Midrex direct reduction plant uses purified Corex gas instead of natural gas as a reducing gas to produce direct reduced iron.

5. Steel is produced by using Corex pig iron and Midrex reduced iron as raw materials.

6. Liquid steel is refined by two-stage ladle furnace (LF) and vacuum oxygen decarburization equipment (VOD).

7. The refined molten steel is cast into a 90 mm thick steel slab of 900 to 1560 mm width by a single-flow thin slab continuous casting machine. A 75 mm thick steel slab was cast under soft pressing.

8. The 90/75mm steel billet is heated by the gas pipeline furnace to the temperature of the coil (1150 °C). It is 20~30mm by two four-pass roughing mills and rolled up by the coiler. Prevent heat loss.

9. Rolled to 1.0 to 8.5 mm thick by 5 four-inch finishing mills. Cool, take up.

10. After smoothing, to further the quality of high steel.

Under the trend of globalization of the world economy, the Saldanha steel plant with new steel production process is very competitive; the cheap supply of cheap ore; the clean production of high quality steel; the reasonable price of electricity and the optimization of energy Use; modern equipment to produce surface quality exchange steel. The completion and operation of the Saldanha steel plant is the first example of the industrialization of a new type of steel production process. It can be used by China's iron and steel enterprises and researchers to combine the construction and transformation of China's characteristics with the 21st century environmental protection requirements and competitive steel enterprises.

Element surfaces can be plain cylindrical, or pleated to increase surface area. Pleated stainless steel cartridge units rated 100microns or finer. You can choose particle retention ratings as fine as 5microns.have an underlying support layer of coarser meshto prevent pleat collapse. Fabrication is by welding and crimping; no silver brazing or epoxy bonding is used.
Sintered mesh filter cartridge is mainly made of high quality stainless steel, including common type and pleated type. They both have high mechanical strengthand pressure tolerance, and the pleated type sintered mesh filter cartridge has larger filtering surface than the common type. They are corrosion resistant and easy to clean. Featured by high durability and long service life, sintered mesh filter cartridges are widely used for liquid and gas filtration, chemical fiber filtration, polyester and water treatment industries.