Cement News tagged under: alite

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Process, mineralogy and cement quality

08 December 2020, Published under Cement News

This month Arthur Harrisson looks at the relationship between temperature differences in the clinker manufacturing process, the composition of clinker produced and the quality of the final cement. Figure 1: variation of iron oxide and alumina in alite with clinker exit temperatures In a project to explore the influence of different temperature profiles on clinker characteristics, a range of commonly available measurements relating to the clinker manufacturing process were matche...

Progress in quantification of clinker phases

21 October 2019, Published under Cement News

The quantification of clinker phases is not always straightforward and often raises a number of questions. However, there has recently been significant progress in this area, as outlined below. Figure 1: share of M3 alite determined by XRD related to MGO/SO 3 The National Institute of Science and Technology (NIST) is an agency of the United States Department of Commerce which, amongst other activities, provides reference samples of cement that have been characterised in terms o...

Crystal clusters in clinker

13 December 2017, Published under Cement News

With increasing use of alternative fuels, short homogenisation times in precalciner kiln systems and the requirement for high alite cement, the presence of crystal clusters is not expected to be a thing of the past. While the impact of crystal clusters in clinker on quality is not always clear, some effects can be seen.  Figure 1: brown and lighter blue belite crystals surrounding liquid phase Cement clinker for general-purpose Portland cement is composed essentially of four...

C2S solid solution reactivity in high-belite cement

28 November 2017, Published under Cement News

The key cause of the high energy intensity in the cement production process is the high heat required to form alite, the main constituent of Portland cement. One option is to lower the alite content, which leads to a higher share of belite. However, such high-belite cement often has a lower early strength, impacting on the quality of the final product. To address this issue, achieving a suitable control of belite reactivity is essential. By Dr Eng Daisuke Kurokawa and Shun Niijima, Taiheiyo...

Crystal inclusions in Portland cement clinker

10 August 2016, Published under Cement News

The nature of inclusions in clinker crystals provides clues about the burning environment and are therefore important indicators of clinker quality. Figure 1: blue belite inclusions in alite crystals Of the four main crystalline compounds that are found in Portland cement clinker, two are produced as solids and two are present in the burning zone of the cement kiln as a liquid, which then crystallises on cooling. Microscopic examination of clinker has been employed as a quali...

How much alite?

18 May 2015, Published under Cement News

The content of alite and other cement phases such as belite, aluminate and ferrite can have significant effects on the strength of the final mortar. This article looks at the correlation between alite and other cement phases on the 28-day strength of cement as well as some of the production conditions required to produce high-quality cement in these circumstances. Figure 1: quantity of alite and 28-day strength from seven cement plants It is well known that the four main phases ...

Alite size

16 July 2014, Published under Cement News

The practical implications following microscopic examination discussed in the April 2013 issue of ICR showed that the interpretation of alite size is not a simple matter. We take a closer look at the relationship between burning conditions, alite crystal size and cement quality. Figure 1: alite crystals averaging 35µm Several factors come into play when considering alite size including flame length and temperature, nucleation, production and kiln conditions, chemical factors, si...

A is for alite

18 June 2012, Published under Cement News

The characteristics of clinker minerals when viewed under the microscope reveal key information about the cement production process. Arthur Harrisson explains their importance, mineral non-equilibrium and mineralogy in practice. He also takes a closer look at the key mineral alite. Optical microscope can reveal a wealth of information about clinker manufacturing processes and clinker properties Cement clinker contains four main minerals, all of which are usually identifiab...