China clay waste as aggregate in alkali-activated cement mortars

Abstract

Every 1 t of china clay produced in the UK generates 9 t of waste material. A limited quantity of the coarser waste has beneficial use as a building stone or secondary aggregate in concrete and asphalt, but there are currently limited uses for the finest waste fraction. 'Mica' waste is a mixture of fine minerals and is one of the forms of waste with little beneficial use other than the restoration of old quarries. With an aim to find new commercially viable and low environmental impact uses in construction, this paper focuses on the use of china clay waste as an aggregate in alkaliactivated cement mortar. Based on preliminary analysis of the compressive strength of binders using slag and fly ash, optimum binders were selected to produce mortars using mica and other forms of china clay waste as aggregate. The mortars were then compared in compression with control specimens using standard sand. Although the results show that the test mortars were generally weaker than the control samples, the paper concludes there are opportunities for their use. Construction Materials Volume 167 Issue CM6 China clay waste as aggregate in alkali-activated cement mortars Zografou, Heath and Walker

An experimental investigation into the use of mica as a material for the stabilisation of marginal clays in construction

“…A significant amount of mining by-product is mica generated both from the mining of relatively valuable materials such as gold, copper, uranium and platinum [13] and that of less valuable materials such as china clay [14] and mica itself [15]. About 10 million tons of mica waste is generated in a year and over 600 million tons of total industry stockpile are estimated to be available [16].…”

On the utilization of mica waste: The pore-fluid chemistry of mica soils and its implication for erosion susceptibility

“…Within the mining industry, the management of mica waste has generated significant attention due to the large volume generated. Mica waste originates from mining of relatively valuable materials such as gold, copper, uranium and platinum (Nosrati et al, 2009), from mining of coarse material such as granite (Hojamberdiev et al, 2011) from the mining of other phyllosilicates such as China clay (Zografou et al, 2014) and from the mining of mica itself (Basak, 2019). For instance, China clay extraction and processing involves the production of a very large quantity of mica waste, typically for every tonne of china clay, one tonne of residual mica is produced.…”

“…Mica waste is usually deposited in large lagoons and abandoned in clay pits. It contains between 10% and 75% mica and currently has seen very limited re-use; within flux for ceramic glazes and as a mild abrasive (Basak, 2019;Hojamberdiev et al, 2011;Zografou et al, 2014).…”

Reuse of Waste from the South West of England in Alkali-Activated Cement Concrete

“…Geopolymers, as known in their generic name, is an alternative to Portland cement with lower CO 2 emissions [10]. A previous paper of this project [11], looking at the performance of the waste in AAC mortar, showed that the increase of the water demand was the main reason for the reduction in the compressive strength of the test mortars using mica and china clay sand. Other authors have looked at the kaolin waste from Brazil with a focus on altering the leftover kaolinite to metakaolin to use it as binder [12][13][14].…”