Portland cement clinker clinkering process

Calcium cyanamid process, for ammonia synthesis, 11 114, 115 Calcium cyanide, 8 194-197 Calcium cyanide diammoniate, 8 195 Calcium dichromate, molecular formula, properties, and uses, 6 561t 5-Calcium disilicate monosulfate, phase in Portland cement clinker, 5 472t 5-Calcium disilicate monocarbonate, phase in Portland cement clinker, 5 472t Calcium disilicide, 4 530 8-Calcium disodium trialuminate, phase in Portland cement clinker, 5 472t Calcium doping, 23 842-844 Calcium P-alumina, 2 406t Calcium ethylenediaminetetraacetate, 7 596t... 

See also Iron entries hydration, 5 477-478 in Portland cement, 5 467 in Portland cement clinker, 5 473t classification of, 11 55-58 crystal chemistry of, 11 59-71 defined, 11 55 energy losses in, 11 64-66 physical properties of, 11 59-71 processing of, 11 71-75 properties of spinel and M-type,... 

Portland cement clinker emerges from a dry process kiln as rounded pellets, or from a wet process kiln as irregularly shaped lumps, in either case typically of 3-20 mm dimensions. Typical clinkers are greenish black, the colour being due to ferrite phase that contains Mg (Ml8) in the absence of Mg , they are buff. Reducing conditions in the kiln typically produce clinkers that are yellowish brown, especially in the centres of the lumps, where less reoxidation has occurred. Light colours can also arise from underburning. 

The burning temperature for production of Portland cement clinker can be decreased by about 150°C through the use of fluxes, but opinions have differed as to the energy saving thereby obtainable, Klemm and Skalny (K52), who reviewed the subject, estimated it at 630kJkg" . Christensen and Johansen (C56) considered that this figure, while possibly realistic for an inefficient, wet process kiln, was unlikely to be so for a modern, precalciner-preheater kiln, in which heat recovery is efficient. They considered a value of lOSkJkg" more realistic. 

Parallel with cement production development the significant progress in cement chemistry was achieved. The real revolution we owe to French scientist Le Chat-eher. This great chemist determined the phase composition of Portland cement clinker and the hypothesis of hydration process. Le Chatelier stated that, similarly as in the case of gypsum, the anhydrite cement components dissolve, the solution became oversaturated in relation to hydrates, which causes their crystallization [3],... 

The chemical composition of clinker is complex, however, it is easy to notice that the sum of four components, CaO, Si02, AI2O3 and Fe203 is as a rule higher than 95 %. The processes of Portland cement clinker phases ciystallization in the four components system can thus be presented. It is especially justified that MgO is not forming own compounds in the rich in calcium part of five-components system, but solid solutions with remaining clinker phases, or is present as periclase. However, the four-components system is seldom used, because the use of ternary systems is much more convenient. They are usually presented as the horizontal projection. 

Kolenova, K.G., "Factors Determining Composition of Aluminoferrife and Aluminate Phases of Portland Cement Clinker and Their Effect on Coating Formation and Clinker Granulation Processes," Sixth International Congress on Chemistry of Cement, Supplementary Paper 1-3, Moscow, 1974,11 pp. 

Maki, I., "Processing Conditions of Portland Cement Clinker as Viewed from the Fine Textures of the Constituent Minerals," Ceramic Transactions, Vol. 40, 1994, pp. 3-17. 

The fundamental use of the microscope in portland cement clinker analysis is to bring to the observer a visual appreciation of phase identities, sizes, conditions, and mutual relationships. With only a basic assemblage of equipment, microscopical analysis can be easily performed, in many cases within a few minutes. The rapidity with which potentially energysaving information can be acquired clearly renders the analysis economicallyjustifiable, especially in routine quality-control and trouble-shooting situations. In addition, the microscope has obvious value in scientific research in the manufacturing process. 

Wang, X., Xiang, Y., and Yang, S. (1991) Formulation process of Portland cement clinker with high sulfate combined mineralizer (in Chinese). Wuhan Congye Dome Xuebao 13,43-49 [ref. CA 118/153077]. 

Table 16.1 gives the energy balance of a clinkering process in which a raw meal of typical composition is converted into an ordinary Portland cement clinker. From the table it is apparent that the reaction in which by far the largest fraction of energy is consumed is the conversion of the calcium carbonate constituting the raw meal into calcium oxide and carbon dioxide ... 

Grinding Aid. An additive to the charge in a ball mill or rod mill to accelerate the grinding process the additive has surface-active or lubricating properties. Grinding aids find particular use in the grinding of portland cement clinker, but in the UK their use is precluded by the conditions laid down in B.S. 12. 

The result of the burning process is Portland cement clinker, consisting of the clinker phases. 

The patented process (European Patent N° 8410186) on which the K-TECH process is based consists in producing an active synthetic base through thermal activation under controlled atmosphere of clayed-calcareous material of specific composition and in producing hydrauhc binder by mixing that base with Portland cement clinker or other activators. 

Teoreanu, L, and Muntean, M., The Kinetics of the Hydration Process of the Silicate Constituents of Portland Cement Clinker Under the Influence... 

In the manufacture of Portland cement, many otherwise-waste materials can be used either as a substitute for the traditional raw material, or as a secondary fuel (e.g., used tires) [334,1577]. In particular, drilling wastes can be introduced in the clinker burning process [878]. For both waste disposal and cement manufacturers, a mutual benefit will emerge. The cement manufacturing companies reduce their demand for traditional raw materials and save the limited capacity of landfills and other waste-treatment industries. 

There are three fundamental stages in the process of manufacture of Portland cement, namely. (I) preparation of the raw mixture. (2) production of the clinker. (3) preparation of Ihe cement. Whether the process used is wet or dry. the raw materials are selected, analyzed, and mixed so dial, alter ireatmeni, Ihe product, or clinker, has a desired, narrowly specified composition A factory analysis of slurry, where the wet process is in use. is as follows calcium oxide 44%. aluminum oxide 3.5%. silicon oxide... 

In the portland cement manufacturing process, three steps occur. First, raw materials are crushed and mixed. The raw materials are powdered limestone, alumina, iron, and silica. Second, the raw materials are fed to an inclined rotary kiln in which they are heated to at least 2700 F. A rock-like substance called clinker is formed, which exits the kiln and is cooled. Third, the cooled clinker is finely crushed, and about 5 percent gypsum is added to produce finished cement. Details of the process are explained below. 

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