The chemistry of Portland cement clinker

Abstract

Technological developments in over a century of production of Portland cement clinker have greatly improved the homogeneity of the feed and clinker leading to much more favourable conditions for alite formation which remains the key chemical reaction in the process. This development is described along with the thermodynamic processes which either enhance the formation of alite by lowering its free energy, or inhibit the formation of alite by lowering the free energy of belite. These processes are always present to some extent depending on the concentrations of minor components in the raw materials and fuels, but can be specifically targeted by the controlled addition of effective mineralisers such as fluoride. This allows further increases in clinker output and reduction in fuel consumption, but perhaps more importantly allows higher contents of supplementary cementitious materials in composite cements for the same cement performance. The same approach can be used to produce new low temperature clinker types such as those based on the so-called Klein's phase.

Separation of Metal Nugget from Self-reduced Product of Coal Composite Stainless Steel Dust Briquette

“…Many researches were carried out on the decomposition of C 3 S, which were verified that the maximum decomposition temperature range for C 3 S was between about 1 025-1 175°C. [12][13][14][15][16][17][18][19][20][21] In the present study, coal composite stainless steel dust briquettes (CCSB) were manufactured through hot briquetting in order to efficiently recycle valuable metals such as chromium and nickel in stainless steel dust. Separation of metal nuggets from self-reduced product of CCSB without using any auxiliary material was focused on.…”

Waste incinerator residue treatment: variability implications

“…According to the concentrations of Cl presented in Table 1 and the mix designs applied, sample 2:3 A5 would contain a Cl concentration equivalent to 37.5% CaCl 2 by weight of C 3 S (assuming C 3 S content of the cement to be 65%w/w (Herfort et al 2010)). However, chlorides are present as a range of salts in APC residues, and additional non-chloride salts are also present.…”

EFFECT OF FERRITE PHASE ON THE FORMATION AND COEXISTENCE OF 3CaO.3Al₂O₃.CaSO₄ AND 3CaO.SiO₂ MINERALS

“…In current researches, adding the CaF 2 mineralizer is the main way to achieve the coexistence of C 4 A 3 $ and C 3 S in the production of clinker [11][12][13]. No doubt that CaF 2 could contribute more to the formation of C 3 S at lower temperatures by lowering its free energy relative to C 2 S [14]. However, CaF 2 has its own drawbacks, for instance, environment pollution owing to fluoride ion, corrosion of the refractory materials in cement kiln, and low the hydraulic activity of cement [15,16], which is restricted in the industrial applications.…”