Clinker color

Clinker color earth brown to light brown to dark brown to black with greenish brown hue In order of increasing degree of burning (Gille and others, 1965)... 

Gray-black clinker color Overall oxidizing environment (Long, 1982b)... 

Disappearance of ferrite phase, iron transformed to metallic state, clinker color changes to white, alite decomposition structures vanish Extreme reducing conditions (Woermann, 1960)... 

Tetracalcium aluminoferrite acts as a processing aid by reducing the clinkering temperature. It hydrates rapidly but does Htde for any performance property of the cured concrete. It does, however, cause most of the color effects in the cured concrete. 

Aliphatic solvents, alkyllithium compounds and, 14 250-251 Aliphatic sulfonates, 26 145 Aliquot samples, 13 413-415 analysis of, 13 416 Aliskren, 5 158 Alitame, 12 42 24 232 Alite, phase in Portland cement clinker, 5 471, 472t, 473t Alitretinoin, 25 790 Alizarin, color of, 7 331 Alizarin derivatives, 9 337 Alizarin pure Blue B, 4 361t Alkadienes, metathesis of, 26 923 Alkali/alkaline-earth cation recognition,... 

The furnace lens provides a 90° or 60° field of view in the same direction as the flame being blown from the burner. Operators can thus watch the complete flame (including length, shape, color, and direction) on the end of the pipe 12 feet away, the sidewalls, top, and bottom of the kiln, the clinker being formed, and the movement of material down the kiln. The camera s quartz lens can see 15-25 feet into the kiln, in contrast to the old vidicon cameras, which could only provide a hazy image over a distance of a few feet. Observing their remote screens, operators can adjust for the most efficient combustion— with pulverized coal igniting at the tip of the feed pipe. 

The white cement clinker should be produced from the pure raw materials, first of all with very low content of Fc203 and MUjOj, which are the most commonly occurring coloring oxides. 

The colored cements can be produced from the white clinker. The technology consists in mixing white cement with mineral dyes, most often the metal oxides, added from 1 to 3 % by mass. There are some reports deahng with alternative colored cements technology, consisting on the production of colored chnkers [37]. 

A staining procedure for calcium fluoroaluminate (rare in normal clinker) was developed by microsco-pists in the 1960s at the PC A laboratories. It is based on the slightly different activities of C A and CjjA CaF. A polished surface of clinker, etched for 3 seconds in distilled water with a pH of 6.5 to 7.0, reveals C A as a bluish color. The surface is then given a second polish and a 30-second etch with a 0.1-molar potassium hydroxide solution that reveals CjjA CaF as a deep brownish-purple hue. Comments on each of these etches follow. 

B. Potassium hydroxide is used for detection of fluoroaluminate. The section surface should be repolished after the water etch. The freshly polished clinker surface is then exposed to 0.1-molar potassium hydroxide solution for 30 seconds. The fluoroaluminate compound is identified by the definitive brownish purple interference color that is deeper in hue and sharper in outline than the one that, as mentioned, is sometimes visible after the 30 second distilled water etch. 

Understanding what one observes in powder mount, polished section, or thin section requires an appreciation of not only the cement manufacturing process but also the varied effects of light as it passes through or is reflected from crystals and amorphous materials. Formal training or extensive experience in microscopy is required. For example, when viewing crushed clinker in cross-polarized light in refractive-index oil on a microscope slide or a thin section, one must be aware that the interference colors are dependent mainly on four factors ... 

Beta dicalcium silicate is metastable below 670°C and monoclinic, with an n ofl.717,an n ofl.722,and of 1.736 and parallel to b birefringence is 0.019. The (h-) 2 Vis 64° to 69°, with the axial plane (010). The beta form exhibits very close polysynthetic twinning (Chromy, 1970). It comprises most of belite in clinker. Cleavage is poor on (100) and (010). Colors range from colorless to yellow or brown. Density is 3.28 Mg/m. Boikova (1980) reported a typical yellow color and spotty surface (not striated). 

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