Phase evolution and pulverization mechanism of self‐pulverizing carbonatable clinkers

Abstract

This paper investigates the phase evolution and pulverization mechanism of a self‐pulverizing carbonatable clinker (SPCC) with a variety of raw material compositions. The particle size, mineral phases, and microstructure of SPCC, produced by sintering at 1400°C for 3 h, were systematically studied by laser particle size testing, XRD/QXRD and SEM/EDS. Results show that clinkers sintered by raw materials with low‐Ca/low‐Al (Ca/Si < 1.6; Al2O3 < 10 wt.%) or high‐Ca/medium‐Al (Ca/Si > 2.6; Al2O3 ≈ 10 wt.%) are non‐pulverized after cooling. The mineral phases of C2AS, CA, and C12A7 are considered to facilitate clinker pulverization at low γ‐C2S contents. With the increase of Al2O3 content in raw materials, SPCC is refined in particle size, accompanied by the significant decrease in the content of calcium silicates. Based on the results, guidelines for producing SPCC are proposed.

Thermodynamic modelling of cements clinkering process as a tool for optimising the proportioning of raw meals containing alternative materials

“…This is desired for some types of cement to reduce costs and CO 2 emissions associated with clinker grinding. This property is usually obtained by changing the volume of the phases during cooling, either by forming new compounds or stabilising higher-volume polymorphs 71 . The thermodynamic modelling did not reveal the formation of recognizably expansive phases (Table 5 ), such as γ-dicalcium silicate (γ-Ca 2 SiO 4 ) or rankinite (Ca 3 Si 2 O 7 ) 102 .…”

“…The boundary conditions determined in the previous dosage steps delimited the risk areas of self-pulverisation during cooling and melting during clinkering. The delimitation of these zones was validated through modelling experimental data of self-pulverising 71 and Portland 23,31,70,[72][73][74][75] clinkers from previous studies.…”

“…The results, parameters, and trends observed in the dosing method were validated based on 21 clinker samples synthesised in eight previous studies 23,31,[70][71][72][73][74][75] . The validation consisted of simulating the clinkers produced by these authors and comparing the results with the trends observed in this study.…”