Life Cycle Assessment Of Cement In China

Cement production in China is the highest in the world, a situation that is likely to persist for some time. Cement production is a process with significant environmental impacts that generates high emissions and consumes substantial resources. The main contents are as follows:1) We conducted a cradle-to-gate comparative life cycle assessment (LCA) of the six common types of cement (Portland cement (PI), ordinary Portland cement (PO), Portland blast-furnace slag cement (PS), Portland pozzolana cement (PP), Portland fly-ash cement (PF), and composite Portland cement (PC)) in China and evaluated their environmental impact potential. The LCA was performed with a model of cement production developed using GaBi4.3. This study was aimed at comparing the environmental impacts of the six cement production processes and identifying the main processes that have the largest effects on the environment during cement production.2) Environmental impacts evaluated in the study included Abiotic Depletion (ADP), Acidification Potential (AP), Eutrophication Potential (EP), Global Warming Potential (GWP), Human Toxicity Potential (HTP), and Photochemical Ozone Creation Potential (POCP). The results indicate that Global Warming Potential (GWP), Acidification Potential (AP) and Abiotic Depletion (ADP) were the primary impact factors.3) In the study, the cement life cycle is divided into five stages:raw material mining, transportation, raw material preparation, calcination, and grinding. Energy consumption and emissions during the calcination and grinding stages are greater than those during transport, raw material mining, and preparation. The calcination stage was associated with significantly higher environmental impacts than all of the other stages combined. Pollutant emissions mainly occur during the calcination stage. The grinding stage, especially for blended cement, is a heavy consumer of power.4) The results show that the total environmental impact potentials of cement production fell in the order PI> PO> PF> PP> PC> PS. The Portland cement production process has the greatest adverse impacts on the environment compared with those of other common cements, and that the Portland blast-furnace slag cement production process has the fewest environmental impacts, even though this alternative is characterized by lower grindability, additional drying, and larger transport distance. Cement mixed with industrial waste may be more environmentally friendly than Portland cement in terms of reducing greenhouse gas emissions, consumption of resources, and overall environmental impacts during the cement production process.