Cement News tagged under: clinker chemistry
Producing boron cement24 August 2021, Published under Cement NewsThe creation of low-energy belite clinker is a specific area of research that aims to reduce CO 2 emissions from the cement manufacturing process. Boron minerals, of which Turkey has 73 per cent of the world’s reserves, are a possible raw material that can be used in the production of belite cements. TÜRKÇIMENTO, the Turkish cement manufacturers’ association has carried out a study into the use of colomonite boron ores to determine their suitability for the production of boron cement. By Se... |
Belite size distribution13 April 2021, Published under Cement NewsBelite size is affected by several factors ranging from raw materials, the length of the burning zone, the fuels used in the production process as well as the conditions in the cooling zone. Figure 1: example of belite crystal size distribution The sizes of belite crystals in Portland cement clinker depend on a number of factors that relate to the raw materials, burning zone length, fuels used and combustion efficiency. Raw materials The relative proportions of alite and ... |
Process, mineralogy and cement quality08 December 2020, Published under Cement NewsThis 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... |
Belite-based low-carbon clinker cements10 March 2020, Published under Cement NewsWhile Portland cement is expected to remain the most-used cement type in concrete production, alternative cements are gaining importance. This has seen the continued development of alternative clinkers, such as belite-based low-carbon clinkers with a belite content of more than 40 per cent, in China over the last two decades. By Tongbo Sui, Sinoma Research Institute, China, Hao Sui, Monash University, Australia, and Bin Wang, Sinoma Research Institute, China. Clinker used in the produ... |
Magnesia in clinker18 November 2019, Published under Cement NewsMagnesia is often present in clinker as periclase, which is formed of free MgO. However, periclase does not always provide a welcome part of the clinker’s composition and can lead to significant volume expansion of the concrete that is made with cement manufactured from such clinkers. Figure 1: periclase inclusions in belite. The belite crystal with two inclusions is 12µm across In cement clinker magnesia (MgO) can be present as a substituent in each of the primary clinker miner... |
Progress in quantification of clinker phases21 October 2019, Published under Cement NewsThe 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... |
Construction and demolition waste as clinker raw material09 September 2019, Published under Cement NewsThe concept of the circular economy encourages the reuse of waste products as raw materials in the production of cement. Arthur Harrisson looks at the use of construction and demolition waste as a raw material for clinker. Initial crushing of concrete produces aggregate containing a significant proportion of mortar Carbon dioxide is produced during cement clinker manufacture from two sources. Firstly, the primary raw material for clinker is limestone, which is predominantly calc... |
Belite in Portland clinker22 July 2019, Published under Cement NewsWhile belite is often represented as a pure dicalcium silicate, in practice the phase contains a range of impurities. Arthur Harrisson highlights the differences in belite composition and examines the causes of such impurities. Type I belite crystals with dark laminations containing exsolved matter The belite phase in Portland cement clinker is often characterised as dicalcium silicate or C 2 S, implying a lime-to-silica ratio of 2:1. The ratio refers to the number of CaO units ... |
Alternative clinkers11 March 2019, Published under Cement NewsThe drive to lower the carbon footprint of cement has led to the development of alternative cement clinkers to replace Portland cement clinker. Arthur Harrisson examines the potential of carbon reduction in four alternative clinker types, as proposed by Gartner and Sui. Belite in clinker Some years ago in ICR the possibilities for using alternatives to Portland cement clinker were discussed. 1 The particular cements examined were calcium aluminate cement (CAC), calcium sulphoal... |
Aluminium and iron in clinker06 February 2019, Published under Cement NewsAluminium and iron are two of the key components in Portland cement clinker. Varying their presence in clinker can have significant effects on the final clinker. Arthur Harrisson looks at some of the impacts of such variations. Figure 1: light grey aluminate and white ferrite very slowly cooled. The hexagonal blue alite crystal below centre is 30µm across The four essential constituents of Portland cement clinker are usually listed as: • calcium oxide (CaO or, in cement chemi... |