SMM11, 10th: at present, the iron and steel industry is facing severe challenges and opportunities for industrial upgrading, and profound changes are taking place in the strategic proposition of the industry. At the 2018 (sixth) China Zinc oxide Industry chain Trading Summit hosted by Shanghai Nonferrous Network, Dr. Guo Yuhua, senior engineer of the General Institute of Iron and Steel Research, described the relationship between iron and steel and zinc, the current strategic adjustment in the development of China's iron and steel industry, and the impact of the adjustment of the iron and steel industry on the production of zinc oxide.
During the 20 years from 1996 to 2016, the cumulative zinc output in China is 71.76 million tons, which is used for the static consideration of iron and steel galvanizing according to the output of 50%. At present, the zinc carried in galvanized steel in China is more than 35 million tons.
In addition to the zinc carried by galvanized scrap steel, there is also a neglected source of zinc in the iron and steel industry: raw materials for long blast furnace-converter steel production. About: 0.336kg/t steel, 270000 tons per year.
Schematic diagram of the relationship between iron and steel galvanizing and zinc oxide production
Zinc is a kind of "harmful" element in the process of iron and steel smelting.
Zinc has a very high vapor pressure and is almost completely insoluble in molten iron and molten steel at high temperatures.
Zinc will bring great negative effects in the smelting process of iron and steel, especially in the process of blast furnace ironmaking.
The main results are as follows: 1. The high content of zinc in the furnace will cause nodulation in the furnace, damage of the furnace lining, cracking of the blast furnace crust and the upwarping or damage of the loose tuyere of the tuyere refractory.
2. Cause the coke ratio to rise and reduce the air permeability of the material column, especially the air window in the soft melting zone;
3. When the iron is discharged, the zinc steam will escape with the molten iron, and the zinc steam will be oxidized into white zinc oxide powder, resulting in poor working environment and poor visibility in front of the furnace.
4. The circulation of zinc steam will also cause the physical heat shortage of slag and iron, the easy cooling of hearth and so on.
Strategic Adjustment facing the Development of Iron and Steel Industry in China
At present, the iron and steel industry is facing severe challenges and opportunities for industrial upgrading, and the strategic proposition of the industry is undergoing profound changes. The proposition of development has changed from "bigger and stronger", "fine product" strategy, to "500" strong and other slogans. Simply meet the market demand, to face a series of severe challenges, such as resource-energy constraints, environmental-ecological constraints, market-brand competitiveness, to solve the higher, towards green, intelligent and other high-level propositions.
Adjustment of the iron and steel industry related to the production of zinc oxide:
Compression and transfer of Iron and Steel production capacity
With the planning and construction of Xiongan New area, Baoding, as an important base for the production of secondary zinc oxide, zinc oxide and zinc baking in northern rotary kilns, is facing shrinkage and industrial transformation and upgrading.
Large-scale Iron and Steel production equipment and Green Manufacturing process
By 2020, blast furnaces under 1000 cubic meters, converters under 100tons and sintering machines under 180m2 will be completely phased out, and blast furnaces under 1500 cubic meters and converters under 150tons will be phased out. The large-scale iron and steel production equipment puts forward more stringent requirements for raw material production, forcing the treatment of zinc-containing slime in iron and steel enterprises.
Electric furnace short process ushered in development opportunity
With the continuous increase of scrap stock, the abundance of electric power, the strict requirements of environmental protection and the guidance of national industrial policy, electric furnace steel in China has ushered in a great opportunity for development.
Wiltz (Waelz) process:
Wiltz process is simple in equipment and mature in technology. However, the process has the advantages of high energy consumption, easy to circle in the rotary kiln, stable production operation, long production cycle, limited treatment scale, and the maximum scale is 150000 tons per year. This method is used to treat zinc dust in more than 100 electric arc furnace soot in Europe, the United States and Japan.
Influence of Iron and Steel Industry Adjustment on Zinc oxide production