Clinkering process mineralizers

Operation with the experimental furnaces has shown that the material properties of coal or ash are only part of the clinkering processes. The geometric shape of the flame, reaction characteristics and heat transmission processes near the wall of the corresponding heating surfaces and on individual particles are coupled with melting, vaporization and condensation processes of mineral substance to form deposits. 

When coal is burned in a combustion unit, mineral matter undergoes major changes that lead to problems of clinker formation, fly ash, slagging, and boiler tube corrosion. The efficiency of a combustion unit is related to the amount of ash produced, since it is a diluent. On the positive side, ash has been utilized as a construction material and is a possible source of refractory materials, as cement additives, or as adsorbents for gas-cleaning processes. However, the composition of the ash must be known before it can be utilized in this way. 

The relative reactivity of the different mineral phases of cement with water is usually given as C A>C S>C S>C AF. Aluminate phases and their hydration products therefore play an important role in the early hydration process. Because of the high reactivity of calcium aluminate, the aluminate hydration reaction is carried out in the presence of sulfate ions. The latter provide control of the reaction rate through the formation of mixed aluminum sulfate products (ettringite and monosulfoaluminate) Calcium sulfate which is added to the cement clinker hence controls the properties of the aluminate hydration products. Sulfates thus play a crucial role in cement hydration and the influence of chemical admixtures on any process where sulfates are involved may be expected to be significant [127],... 

Thermal processes Sintering 2-50 High to very high Up to 100 tons/h Strongest bonding Ferrous and nonferrous ores, cement clinker, minerals, ceramics... 

Potassirrm and soditrm introduced to the raw meal with clay minerals are not desirable in the process of clinker phases formatioa However, at low temperature they... 

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. 

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]. 

The clinker formation process is initiated by the dehydration of gypsum to anhydrite at around 100-120°C, followed by a decomposition of clay minerals at around 300-600°C. The decaibonization of the calcium carbonate that is present starts at about 700°C, and is completed before the temperature reaches 900°C. 

Bikbaou, M. (1980) Mineral formation processes and phase eomposition of alinite clinker, m. Proceedings 7th ICCC, Paris, Vol. 4, pp. 371-376. 

By mixing Portland cement with water, the hydration process begins. The hydration process is the combination of physical and chemical changes during which, the cement previously mixed with water becomes a porous sohd. During this process a number of exothermic reactions give rise to cement matrix. In the case of Portland cement, the main reactions are based on interaction between two mineral components present in higher proportion clinker and water. These reactions can be written in simplified form thus [30, 65, 66] ... 

Figure 5.9 summarizes the processes that occur during the hydration of anhydrous clinker minerals (left-hand column) to form the products shown in the right-hand column. The rectangular areas occupied by the individual phases correspond approximately to their volumetric proportions in Portland cement. 

Fig. 17.1 Flow diagram for the manufacture of Portland cement by the wet process. The limestone is crushed, mixed with wet clay, and ground to a fine slurry in a mill. This raw material is stored and corrected for composition by blending before being fired in a rotary kiln where the process of water evaporation, mineral dehydration, limestone dissociation, and chemical reaction proceeds. Clinker formation forms finally at 1,450 °C and is cooled and ground with additives before storage... 

Typical applications for this type of conveyor are in the heavy duty areas of mining or minerals processing or power generation. Their simple geometry and robust nature make them ideal for handling materials such as hot cement, clinker and ash or wet mineral ores, coal and grain. Construction materials may be malleable iron or hardened steel for heavier duties. 

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