Research on innovation and development strategy of green metallurgy

In recent years, with the acceleration of the withdrawal of backward production capacity, the rapid development of short process steelmaking, and the continuous improvement of the level of energy-saving technology and equipment, the comprehensive energy consumption of tons of steel in China's enterprises has continued to decline, and will be 0.551 tce in 2020 (down 3.7% from 2015), and the gap with the world's advanced level has gradually narrowed. Despite this, due to the huge industry capacity, the steel industry's energy consumption in 2020 accounted for more than 13% of the total energy consumption of the whole society. Subsequently, China will fully implement the ultra-low emissions of the steel industry, expand new ways of energy conservation and emission reduction, and achieve green and sustainable development of the steel industry; Based on the guidance of the concept of high-quality development, maintaining and even expanding the future development space of the steel industry is also a problem to be faced.

The emission intensity of pollutants in China's steel industry has entered the ranks of the world's advanced levels. In 2020, the new water consumption per ton of steel in steel enterprises will drop by 4.34% year-on-year, chemical oxygen demand by 10.11% year-on-year, and SO2 emissions by 14.38% year-on-year. The utilization rate of steel slag increased by 0.98 percentage points year-on-year, and the utilization rate of coke oven gas increased by 0.08 percentage points year-on-year [9].

China's steel industry technology and equipment as a whole has reached the international advanced level, and even leads the world in the comprehensive capacity of steel industry design and equipment manufacturing, construction and construction. Steel smelting has entered a stage of development dominated by independent innovation and integrated innovation. In the slag splashing furnace [10] and long life reblowing process [11,12], thin slab continuous casting and rolling high efficiency production technology [13,14], "negative energy steelmaking" process and equipment technology [15,16], high efficiency and low cost clean steel production technology [17], carbon reduction melting reduction technology [18], hydrogen steelmaking technology [19,20], steel enterprises intelligent manufacturing technology [21] and other aspects have made a series of achievements.

2. Problems faced by the development of iron and steel metallurgy

Iron ore is an important raw material for iron and steel production enterprises, and the grade of iron ore in China is poor, and the qualified iron concentrate mineral rate is low. In response to the needs of infrastructure construction, the demand for iron ore in China has increased significantly, and the independent supply can not meet the demand for steel production, and can only rely on imports to make up for the gap between supply and demand.

In recent years, the regional distribution of construction projects in China's iron and steel industry is not well balanced, showing a pattern of "more south and less north"; The proportion of special steel production is low, and the proportion of high-end special steel is lower, and some imports are still needed to meet the needs of equipment development.

China's iron and steel industry in the technical system, green development and other aspects have made significant improvements, but the iron and steel metallurgy faced by the resource/energy/environmental load increase, complex process, high carbonization of energy structure and other problems have not been eliminated, to achieve carbon peak, carbon emission reduction, carbon neutrality facing great challenges.

(2) Status and challenges of non-ferrous metallurgy

1. Development status of non-ferrous metallurgy

In recent years, the transformation and upgrading of China's non-ferrous metal industry has achieved remarkable results, mainly reflected in the improvement of scale advantages, the output of crude copper, refined copper and electrolytic aluminum ranks first in the world, and new progress has been made in the adjustment of production capacity structure. Green transformation has taken on a new look, innovation capacity has reached a new level, and intelligent manufacturing has reached a new level.

China is the world's largest production and consumption of non-ferrous metals, 10 kinds of commonly used non-ferrous metals in the world accounted for long-term stability of more than 50%. In 2020, the total output of non-ferrous metals will be 6.188×107 t, among which the output of refined copper and copper materials will be 1.003×107 t and 2.046×107 t, respectively, with year-on-year growth rates of 7.4% and 0.9% [22]. The output of alumina, electrolytic aluminum and aluminum was 7.313×107 t, 3.708×107 t and 5.779×107 t, respectively, with year-on-year growth rates of 0.3%, 4.9% and 8.6%, respectively. The scale of the recycled non-ferrous metal industry continues to grow, and the total output in 2020 will reach 1.45× 107t, accounting for 23.5% of the total output of 10 kinds of non-ferrous metals. Among them, the output of recycled copper is 3.25×106 t (corresponding 32.4%), the output of recycled aluminum is 7.4×106 t (corresponding 20%), and the output of recycled lead is 2.4×107 t (corresponding 37.25%) [7].