Photomicrographs of Free Lime

Photograph 7-79 Free-lime nest colored by water etch in polished section. Chemical analysis gave clinker free-lime value of 2.69%. High maximum temperature, moderately long burning time, moderately slow heating rate, moderately slowly cooled, 31 MPa. Gas-fired, dry-process kiln, 3000 tons/day. (S A6697) 

Photograph 7-80 Strongly zoned, tan alite with free-lime inclusions and round, coarsely lamellar belite with tan cores, the latter believed to have a relatively low calcium-to-silicon ratio. Coarse seashells in feed. 

Coal- and coke-fired, semiwet-process kiln, 1850 tons/ day, 44 MPa. (S A6698) 

Photograph 7-81 Free-lime nest from coarse calcite particle in raw feed. Very low liquid phase. Coal- and coke-fired, dry-process kiln. Moderately high maximum temperature, long burning time, moderately fast heating rate, quick cooling rate. (S A6699) 

Photograph 7-82 Free lime in clinker thin section. Crystals exhibit prominent cubic cleavage characteristic of free lime. An abundance of free-lime nests (some showing original limestone particle outline), anhedral alite, and extremely nonuniform distribution of silicates suggests poorly mixed coarse feed. Dry-process kiln, coal fired. (S A6700) 

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