<p>Production data from two typical alumina plants—one using the high-temperature Bayer process with diaspore and the other using the low-temperature Bayer process with gibbsite—were subjected to life cycle assessment (LCA). The results indicate that the total environmental impact of alumina production by the Bayer process with diaspore is 1.85 times that of gibbsite, that is, the environmental impact is significantly influenced by fuel types and lime dosage. The environmental impact of alumina production with diaspore is ranked as follows: digestion unit (28.66%), evaporation unit (28.41%), and raw material preparation unit (20.46%), while the environmental impact generated by gibbsite is ranked as follows: digestion unit (43.70%) and evaporation unit (30.87%). Steam has the greatest sensitivity to environmental impacts of two types of ore, at 37.86% and 59.42%, respectively. Based on China’s 14th Five-Year Plan energy conservation and emission reduction targets, the emission reduction potential of alumina production with diaspore and gibbsite is 18.13% and 17.56%, respectively, with CO₂ accounting for nearly half of the environmental impact. In summary, improving heat utilization, reducing steam and lime consumption, and adopting clean energy production are important ways to conserve energy and reduce emissions.</p>