Sustainable Mining and Metallurgy

This paper introduced the relevant standards, classification and calculation methods of greenhouse gas emissions, focused on the calculation method of carbon emissions in the electrolytic aluminum process, and put forward the carbon reduction direction of electrolytic aluminum production. The carbon emission of the electrolysis process involves direct emission (scope I) and indirect emission (scope II), namely, the PFCs emission generated by the net anode consumption and anode effect, as well as the emission of purchased power. The net anode consumption per ton of aluminum emission calculated according to the recommended value is 1.503tCO₂e, and the PFCs per ton of aluminum emission generated by the anode effect is 0.252tCO₂e. The net consumption of aluminum per ton of anode calculated according to the measured data is basically below 1.5tCO₂e, while the PFCs emission calculated from the measured data fluctuates greatly from 0.32 to 2.38tCO₂e/t, both of which are greater than 0.252tCO₂e. The electricity consumed in electrolytic aluminum production is the largest indirect emission in the aluminum production process. Due to different power supply emission factors, its emission is 0~16.2tCO₂e/t. Standardized and unified calculation and measurement methods are the prerequisite for obtaining accurate emission data. Relevant national departments and large aluminum industry groups should actively organize the measurement of direct emissions of electrolytic aluminum industry, especially PFCs emissions. Reducing anode consumption and anode effect is the key to reduce the direct emission of electrolytic aluminum process, saving electricity is the key to reduce indirect emission, saving the consumption of raw and auxiliary materials such as aluminum oxide is an important means, and adopting green electricity with low emission factor is also an important direction of carbon reduction.