00/01033 Influence of pulverized coal fineness on the formation of NOx in rotary kilns in the cement industry

2000 ◽  
Vol 41 (2) ◽  
pp. 114
Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 209
Author(s):  
Mónica Antunes ◽  
Rodrigo Lino Santos ◽  
João Pereira ◽  
Paulo Rocha ◽  
Ricardo Bayão Horta ◽  
...  

Currently, the production of one ton of ordinary Portland cement (OPC) releases considerable amounts of CO2 into the atmosphere. As the need and demand for this material grows exponentially, it has become a challenge to increase its production at a time when climate-related problems represent a major global concern. The two main CO2 contributors in this process are fossil fuel combustion to heat the rotary kiln and the chemical reaction associated with the calcination process, in the production of the clinker, the main component of OPC. The current paper presents a critical review of the existent alternative clinker technologies (ACTs) that are under an investigation trial phase or under restricted use for niche applications and that lead to reduced emissions of CO2. Also, the possibility of transition of clinker production from traditional rotary kilns based on fuel combustion processes to electrification is discussed, since this may lead to the partial or even complete elimination of the CO2 combustion-related emissions, arising from the heating of the clinker kiln.


2017 ◽  
Vol 58 (1) ◽  
pp. 5-9 ◽  
Author(s):  
L. M. Aksel’rod ◽  
O. N. Pitsik ◽  
I. G. Maryasev ◽  
O. A. Maryaseva ◽  
V. A. Ustinov

Author(s):  
М.Ш. Саламанова ◽  
С.А. Алиев ◽  
Р.С.-А. Муртазаева

В процессе обжига портландцементного клинкера в электрофильтрах вращающихся печей скапливается большое количество пыли, как клинкерной, так и аспирационной, поэтому рациональное использование этих продуктов, содержащих определенную долю полноценного сырьевого ресурса, является актуальной задачей индустрии цемента. В данной работе представлены результаты исследований цементной пыли, проведен энергодисперсионный и сравнительный анализ исследуемых порошков, а также приводится возможный способ утилизации цементной пыли для получения бесклинкерных цементов щелочной активации и бетонов на их основе. Разработанные рецептуры бесклинкерных вяжущих с применением отходов цементной промышленности и натриевого жидкостекольного затворителя позволят получать менее затратные, прочные и долговечные композиты, которые позволят частично заменять традиционный бетон на дорогом портландцементе. Работа выполнена в рамках исследований по реализации научного проекта 1848200001 Высококачественные бетоны с повышенными эксплуатационными свойствами на основе местного природного и техногенного сырья , получившего поддержку Российского фонда фундаментальных исследований (РФФИ). In the process of firing Portland cement clinker in electrostatic precipitators, in rotary kilns, a large amount of harmful substances, both clinker and aspiration, accumulates, therefore rational use of these products leads to certain shares of a fullfledged river resource, which are derived from industrial cement. It should be noted that the reuse of dust electrostatic precipitators is impossible. The basis for obtaining durable and more resourceefficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder. The developed clinkerfree binder formulations using the cement industry wastes and sodiumbased sludge glass will make it possible to produce less expensive, durable, and durable composites that will partially replace traditional concrete with expensive portland cement.


Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 974
Author(s):  
Shuai Wang ◽  
Yufeng Guo ◽  
Kuo Liu ◽  
Zhuang Yang ◽  
Yajing Liu ◽  
...  

The deposit-forming problem is one of the main bottlenecks restricting the yield and production benefit of iron ore pellets produced by coal-fired rotary kilns. In order to implement measures to ensure the efficient production of pellets by coal-fired rotary kilns, the mechanism and influencing factors on the deposit formation were reviewed. The pellet powder and coal ash come together to form the material base of the deposit. Meanwhile, the local reducing atmosphere caused by the continued combustion of residual carbon increases the FeO content, resulting in the formation of low-melting-point silicates. Moreover, alkali metal elements in coal ash can also promote liquid phase formation to cause serious deposit aggregation problems. During high-temperature roasting, the liquid phase corrodes the surface of the refractory brick to form the initial deposit, whereafter, it binds the pellet powder and coal ash from the material layer, which causes the deposit to accumulate continuously. The deposit formation of coal-fired rotary kilns is the result of interaction between many factors, which includes the quality of the green pellets, the composition of coal ash, the combustion efficiency of pulverized coal, roasting temperature, FeO content and alkali metal input. Finally, it is recommended that some measures to mitigate deposit formation can be adopted, such as increasing the compression strength of preheated pellets, choosing high-quality raw materials with low alkali metals, improving the combustion of pulverized coal.


Author(s):  
S. A. Aliev ◽  
R. S.-A. Murtazayevа ◽  
M. Sh. Salamanova

Objectives In the process of firing Portland cement clinker in electrostatic precipitators, in rotary kilns, a large amount of harmful substances, both clinker and aspiration, accumulates, therefore rational use of these products leads to certain shares of a full-fledged river resource, which are derived from industrial cement. It should be noted that the reuse of dust electrostatic precipitators is impossible.Method The basis for obtaining durable and more resource-efficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder.Result The basis for obtaining durable and more resource-efficient composites is based on modern technological methods that contribute to the improvement of technical and physicomechanical properties, with the integrated application of technogenic raw materials and liquid sodium binder.Conclusion The developed clinker-free binder formulations using the cement industry wastes and sodium-based sludge glass will make it possible to produce less expensive, durable, and durable composites that will partially replace traditional concrete with expensive portland cement. 


1898 ◽  
Vol 46 (1192supp) ◽  
pp. 19108-19109
Author(s):  
Bernard L. Green

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