WUHAN UNIVERSITY OF TECHNOLOGY

Application of new types of retarders in improving the properties of FGD gypsum

Flue-gas desulfurization (FGD) gypsum is a solid by-product from the exhaust of coal fired plants. Due to the low price and abundant availability of FGD gypsum, the material has a good potential for application in building materials after calcination to ß-calcium sulfate hemihydrate (ß-HH). However, the very short setting time of this binder system becomes a problem. In this paper, experiments with different retarders showing influences on setting and hardening processes are examined. The effects on setting time, crystal size, morphology and its solution-precipitation processes are detectable by X-Ray Diffraction (XRD), scanning electron microscope (SEM) and a digital microscope.

1 Introduction

China is a developing country with coal as its main energy resource. The energy infrastructure is dominated by the coal fired power industry. Taking 2012 as an example, the yield of coal in China was 3.65 billion tons [1]. In contrast, its consumption was about 4 billion tons. The entire emission of SO2 in China was 21 176 million tons, among which more than 20 million tons was due to the combustion of coal and more than 50 % was generated from thermal power plants [2-3]. It is estimated that by 2020, the coal yield in China is going to rise to 4.8-5.3 billion tons [4], so the...

Related articles:

Issue 11/2017 URAL-OMEGA, PJSC

Aspects of gypsum dihydrate crystallization in the artificial aging of gypsum binder

1 Introduction The search for effective technological operations to stabilize technical characteristics used in producing gypsum binders has received a great deal of attention in recent years owing to...

more
Issue 6/2017 SIKA SERVICES AG

The spice of gypsum

1 Background Gypsum boards are produced from gypsum plaster, water and additives for the gypsum core as well as cardboard on continuous conveyor lines. Prior to diving into the chemistry of gypsum...

more
Issue 03/2009 Materials Science

Acceleration of the setting of hemihydrate plaster with calcium sulfate dihydrate

1 Introduction Calcium sulfate binders are required to have widely varying properties to meet technical and economic requirements. In particular, it has to be possible to vary the workability time and...

more
Issue 7-8/2010

Quantification of structure formation in setting stuccoes influenced by additives

1 Introduction The setting of stucco is controlled by means of the addition of additives. These generally cause acceleration or retardation of the rehydration of the hemihydrate to dihydrate. In many...

more
Issue 2/2021 LUOYANG INSTITUTE OF SCIENCE AND TECHNOLOGY  WUHAN UNIVERSITY OF TECHNOLOGY  HUBEI UNIVERSITY OF TECHNOLOGY

Research into the effect of accelerators on the properties of α-hemihydrate gypsum slurry

1 Introduction Because they count as green building materials, gypsum-based materials have been widely used in wall materials, grouting materials and flooring materials due to their superior...

more