Research on innovation and development strategy of green metallurgy

The comprehensive energy consumption of key metals in the non-ferrous metal smelting industry has gradually decreased. In 2020, the comprehensive energy consumption per unit of electrolytic aluminum will decrease by 1% year-on-year; The comprehensive energy consumption of tons of copper smelting decreased to 0.212 tce, and the comprehensive energy consumption of some smelting enterprises was below 0.15 tce, reaching the international top level of the industry; Overall energy consumption per ton of lead decreased from 0.467 tce in 2012 to 0.345 tce; The coal consumption of 1 kg molybdenum oxide roasting decreased from 0.4 tce to zero. In terms of CO2 emissions, the non-ferrous metal industry will be 6.6×108 t in 2020, accounting for 4.7% of the country's total emissions. Among them, the CO2 emissions of the aluminum industry are about 5.5×108 t, the smelting industry of copper, lead, zinc and other non-ferrous metals accounts for about 9%, and the copper and aluminum rolling industry accounts for about 10%.

The non-ferrous metal metallurgy industry has made significant progress in environmental protection. Electrolytic aluminum enterprises in key air pollution prevention and control areas have reached ultra-low emission levels as a whole, such as flue gas emission particles below 10 mg/m3, SO2 reduced to 35 mg/m3, and fluoride less than 1 mg/m3. Various technical and economic indicators of copper smelting have been continuously optimized, and the sulfur capture rate and recovery rate of copper smelting enterprises have reached 99%. The alumina industry has initially realized the comprehensive utilization of red mud, and the comprehensive utilization of recoverable iron, alkali and other valuable elements and products exceeds 25% of the output.

The overall level of China's non-ferrous metal industry technology and equipment has entered the ranks of the world's advanced. With 500 kA, 600 kA large aluminum electrolytic cell, new cathode structure and other aluminum electrolytic energy saving technology as the representative, electrolytic aluminum industry technology has reached the international leading level; Represented by oxygen bottom blowing/side blowing copper, oxygen top blowing copper, double flash smelting copper, copper smelting industrial technology has reached the world's first-class level; Lead, zinc, nickel, tin smelting technology to reach or close to the international advanced level; Major progress has been made in magnesium, titanium, tungsten, molybdenum smelting, and rare earth smelting and separation.

2. Problems facing the development of non-ferrous metallurgy

The non-ferrous metal industry is facing a new situation of high-quality development, such as electrolytic aluminum and other products demand is about to enter a plateau period, and the expansion of large-scale demand is weakening.

China's non-ferrous metal resources recycling rate is low (only 30%), while developed countries generally more than 70%. The industrial positioning of recycled non-ferrous metals has been adjusted to energy conservation and environmental protection industry and strategic emerging industry, and its importance in resource environmental security and economic and social green development has been highlighted. However, compared with the primary mineral resources, the secondary non-ferrous metal resources have the characteristics of raw material source uncertainty, resource richness and diversity, high component complexity, high component content volatility, high material density and compound, etc., and the recovery and treatment process is relatively complex.

The problem of "three wastes" produced by non-ferrous metal metallurgy industry is still prominent. As of 2020, the cumulative stockpile of tailings in China is about 2.07×1010 t, of which copper tailings are about 3.5×109 t and tungsten tailings are about 4.5×108 t. The total amount of tailings comprehensively utilized is about 3.35×108 t, and the comprehensive utilization rate is only 28%. The production of smelting waste slag is about 3.7×105 t, including red mud, copper slag, nickel slag and so on. Therefore, the situation of energy conservation, emission reduction and comprehensive utilization of resources in the non-ferrous metal industry is complicated and the task is arduous.