The influence of phosphorous pentoxide on the phase composition and formation of Portland clinker

Staněk, Theodor; Sulovský, Petr

doi:10.1016/j.matchar.2008.11.013

Cited by 32 publications

(19 citation statements)

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“…With the increasing content of P 2 O 5 , CaO does not completely react with belite to form alite even after 4 h burning at 1450 °C, which can be considered as equilibrium burning. Alite formation is completely blocked at 4.5 wt% of P 2 O 5 in the clinker [8].…”

Section: Introductionmentioning

confidence: 93%

“…The combustion residues, consisting of calcium phosphate (mainly hydroxylapatite-Ca 5 (PO 4 ) 3 (OH)) then react with clinker in its whole volume. P 2 O 5 influences clinker melt properties [3], enters into the structure of clinker phases [4] and influences the phase composition of clinker [5][6][7][8] and thus the quality of the cement [7,9].…”

Section: Introductionmentioning

confidence: 99%

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Mechanism and kinetics of binding of meat and bone meal ash into the Portland cement clinker

2020

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Meat and bone meal (MBM) is the alternative fuel with good calorific value used in cement production. The main problem with MBM combustion in a cement kiln is the high content of P 2 O 5 , which incorporates in clinker phases, influencing phase composition of clinker and hence the quality of the cement. In cement industry, only limited amount of MBM is burned to prevent adverse effect. P 2 O 5 has a significantly negative effect on the formation of the main clinker phase alite and it stabilizes belite by means of entering its structure. At 4.5 wt% P 2 O 5 in the clinker, the alite formation is completely blocked. Research on kinetics of reactions between clinker and MBM proved reduction of negative reactions and minimization of migration of P 2 O 5 into the clinker minerals using undispersed P 2 O 5 carrier. The carrier in pellet form eliminates the negative effect of P 2 O 5 on the formation of the alite. The research was conducted by means of XRD, optical and electron microscopy. Electron microanalysis showed that P 2 O 5 migrated inside the clinker to a distance of less than 250 μm from the ash and clinker interface. Clinker was not influence outside this area. It is possible to prepare high quality cement from the clinker containing ash residues from MBM in an amount corresponding to up to 10 wt% P 2 O 5. The work was completed with preparation of cement with 7 wt% of P 2 O 5 , which exhibited good technological properties. In addition, these cements significantly reduce the leachability of toxic elements.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Mechanism and kinetics of binding of meat and bone meal ash into the Portland cement clinker

2020

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“…Phosphorus has been shown to negatively influence the formation of alite and increases the amount of belite and CaO(s) formed. With increasing amounts of phosphorus pentoxide in the raw material of clinker, phosphorus was shown to primarily enter the belite phase and to a lesser extent the alite phase (Gutt, 1963;Nastac et al, 2007;Stanek and Sulovsky, 2009). At concentrations above 1% phosphorus pentoxide, a solid solution of phosphorus and belite forms (Nurse, 1952).…”

Section: Theoretical Calculationsmentioning

confidence: 99%

“…The use of waste-derived fuels (agricultural crops, animal meat, bone meal) results in increased phosphorus content in cement. It has been shown that phosphorus decomposes or inhibits the formation of alite while stabilising belite and generating free lime (Halicz et al, 1984;Nastac et al, 2007;Nurse, 1952;Stanek and Sulovsky, 2009 On the phase chemistry of Portland cement clinker Hö kfors, Boströ m, Viggh and Backman (Nastac et al, 2007). At concentrations of 0 .…”

Section: Influence Of Phosphorus On Clinker Mineralsmentioning

confidence: 99%

“…The use of wastederived fuels from agricultural crops, animal meat or bone meal, for example, leads to increased phosphorus content in cement. It has been shown that phosphorus decomposes or inhibits the formation of alite while stabilising belite and generating free lime (Halicz et al, 1984;Nastac et al, 2007;Nurse, 1952;Stanek and Sulovsky, 2009). The amount of alite in cement is of great importance because it is the most important contributor to the development of strength in concrete in the first 28 d. Because phosphorus is expected to increase when traditional fossil fuels are replaced with alternative biomass-based fuels, both theoretical and practical studies on how an increased phosphorous content influences clinker minerals have been performed.…”

Section: Introductionmentioning

confidence: 99%

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On the phase chemistry of Portland cement clinker

Hökfors¹,

Boström²,

Viggh³

et al. 2015

Advances in Cement Research

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This paper describes the formation of a phosphorous belite solid solution and its impact on alite formation. A subsolidus phase relation for the ternary system silicon dioxide-calcium oxide-phosphorus pentoxide (SiO 2 -CaO-P 2 O 5 ) is reported. The ternary system is based on Rietveld refinements of X-ray diffraction patterns from experimental tests. The overall picture is based on known phase diagrams, relevant Rietveld refinements models, stoichiometric relationships as a function of increasing phosphorus pentoxide concentration and vacancy theories for solid solutions of phosphate belites. A tool is developed for predicting the chemistry of the product as well as the chemistry during heating when producing Portland cement clinker. A thermodynamic database for phase chemistry calculations of clinkering reactions has been created and evaluated. Suitable compounds and solution species have been selected from the thermochemical database included in FactSage software. Some solution compositions have been uniquely designed to allow for the proper prediction of the cement clinker chemistry. The calculated results from the developed database for heating raw materials in cement clinker production and cooling of the product are presented in this paper. The calculated results provide a good prediction of the phases and quantities formed during heating and non-equilibrium cooling. The prediction of the amounts of alite, belite and aluminoferrite phases in the product according to the Scheil method is good. The temperature interval for the existence of all of the major phases is relevant. The thermodynamic data for a solution phase of alite with substituting ions of primarily magnesium oxide and phosphorus pentoxide would improve the predictability of the developed database.

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