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General comment The Chinese LCI data are calculated with a sample of 18 cement plants with 30 production lines all over China (China Centre of National Material Life Cycle Assessment, 2012).There are three primary production processes .The pulverized coal and raw meal preparation process include the transferring, grinding, homogenizing, and storage of raw materials, and the grinding and storage of coal. In the burning process, the ground and mixed raw materials-raw meal are input to the preheater, and then to the calciner, decomposing with 60 % of coal at 950 °C. The limestone decomposes for about 95 % in the calciner and for 5 % in the kiln. The decomposed materials fall into the kiln and are incinerated to be clinker with 40 % of coal at a temperature of over 1,400 °C. In the finishing process, the cement is produced when clinker, mineral additions, and gypsum are granulated finely by grinding mill. The raw meal is suspended and heated by recycled hot air in preheater. |
