Fig. 4 (a) shows that gypsum crystals without any retarder are mainly needle-like, with many overlap points among the crystals, compact structures and better pore structure. Download: Download high-res image (887KB) Download: Download full-size image; Fig. 4. Effects of different retarders on setting times of building gypsum under …
The industrial byproduct gypsum is a general term for byproducts discharged from industrial production with calcium sulfate as the main ingredient. Due to the high number of impurities and production volume, the industrial byproduct gypsum is underutilized, leading to serious environmental problems. At present, only …
This study deals with the retardation of cement setting time and workability in hot weather such as in Sultanate of Oman. Combination of sugar and gypsum...
The desulfurized gypsum treated with hydrogen peroxide can improve the stability of cement. When the proportion of desulfurized gypsum and natural gypsum is …
Flue gas desulfurized gypsum (FGD gypsum), mainly originates from thermal power plants, smelters, and large-scale enterprise boilers.This article reviews the production in China and the latest beneficial utilizations of FGD gypsum. China is a large coal-consuming country and has always had serious SO 2 emissions. Therefore, the …
DOI: 10.1016/j.conbuildmat.2022.127630 Corpus ID: 248445855; Modification of phosphogypsum using circulating fluidized bed fly ash and carbide slag for use as cement retarder @article{Li2022ModificationOP, title={Modification of phosphogypsum using circulating fluidized bed fly ash and carbide slag for use as cement retarder}, …
In this paper, the possibility of flue gas desulphurization (FGD) gypsum as an admixture in cement and concrete was explored. The gypsum was baked at the proper temperature of 200 °C for 60 min ...
The invention discloses a method for preparing gypsum powder for a ceramic mould in the ceramic industry, wherein the desulfurized product of power plants, i.e., desulfurized gypsum, is mainly used as a main raw material for the gypsum powder for the ceramic mould. The method comprises the steps of: calcining the desulfurized gypsum in a …
The influences of desulfurization gypsum on the properties of both Magnesium oxychloride cement (MOC) pastes and MOC abrasive tools were investigated in this study.
Flue gas desulfurization gypsum (FGDG) is a coal combustion by-product that can be used in various beneficial ways. This review summarizes the recent …
The effects of the retarder type and content on the setting inhibition and mechanical properties of desulfurized gypsum were evaluated. The experimental results showed that all three retarders had different degrees of retardation on desulfurized gypsum; among them, citric acid had the best retarding effect.
The desulfurization gypsum are widely utilized in cement retarder, building material, embedment and neutralizer or regulator of soil in agriculture [3, 4]. At same time, decomposing of desulfurization gypsum or Phosphogypsum to producing ( {text{CaO}} ) and ( {text{S}}{{text{O}}_2} ) is another promising utilization method for cement as ...
The synergistic effect of red mud – desulfurized gypsum - fly ash was found. ... DG contains a large amount of sulfate, which is often used as a retarder in cement-based materials, with a dosage generally less than 3%. When the sulfate content in cement is high, it will delay the setting time of the cement, and a large amount of …
In the limestone gypsum flue gas desulfurization process, 2.7 ton of desulfurized gypsum can be generated for each 1 ton of SO 2 removed . ... Caillahua et al. used FGDG instead of natural gypsum as retarder of Portland cement. They found that FGDG retardation took 1 h longer compared to natural gypsum, and the composition of …
Cement clinker minerals, mineral powder, and active calcium aluminate were dissolved in water to produce Al(OH) 4− and OH − after water was added to the Portland cement-fly ash-calcined FGD gypsum-calcium aluminate composite quaternary cementitious system. The desulfurized gypsum also dissolved SO 4 2− and Ca 2+ …
Alternative calcium-sulfate-bearing materials as cement retarders: part II. FGD gypsum. Cem Concr Res. (2004) M.A. Pedreño-Rojas et al. Life cycle assessment of natural and recycled gypsum production in the Spanish context. J. Clean. Prod. ... Moreover, the solid waste desulfurized gypsum is used as a sulfate activator. The …
the limestone gypsum flue gas desulfurization process, 2.7 ton of desulfurized gypsum can be generated for each 1 ton of SO2 removed [3]. A 300 MW coal-fired thermal power unit discharges about 30,000 ton of desulfurized gypsum every year (assuming 1.0% sulfur in coal) [4]. A substantial amount of desulfurized gypsum is generated as a by …
6–79.8% of Hg in FGD gypsum could be reemitted at 100–200 °C.. The Hg release ratio is directly related to the HgClx content in FGD gypsum.. Wallboard production and being used as cement retarder were two main Hg re-emission pathways of FGD gypsum utilization.. The secondary Hg emission from FGD gypsum utilization …
The effects of desulfurized gypsum, heat-treated desulfurized gypsum and hydrogen peroxide modified desulfurized gypsum on the setting time of Portland cement were studied. The results showed that when the content of desulfurized gypsum after 80 °C heat treatment was 4% of Portland cement, the initial setting time was 136min, and …
The desulfurization gypsum are widely utilized in cement retarder, building material, embedment and neutralizer or regulator of soil in agriculture [3, 4]. At same …
The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), …
1. Introduction. Flue gas desulfurization gypsum (FGDG) is an industrial byproduct produced by limestone-gypsum wet desulfurization to treat SO 2 produced by thermal power plants and coal-fired plants, whose main component is CaSO 4 ·2H 2 O. In wet desulfurization, 1 t of SO 2 produces about 2.7 t of FGDG [1], [2].Some 130 million …
the limestone gypsum flue gas desulfurization process, 2.7 ton of desulfurized gypsum can be generated for each 1 ton of SO2 removed [3]. A 300 MW coal-fired thermal power unit discharges about 30,000 ton of desulfurized gypsum every year (assuming 1.0% sulfur in coal) [4]. A substantial amount of desulfurized gypsum …
Concrete/cement and asphalt production . Natural gypsum can be used in concrete production as a replacement for calcium aluminate cement (CAC), opening the possibility of replacing the natural gypsum with FGDG in this application with success, even though some studies have reported a reduction of compressive strength and water …
The invention discloses a desulfurized gypsum retarder, a preparation method and application thereof in sulphoaluminate cement, wherein the method comprises the following steps: the temperature of the rotary kiln is reduced from 300 ℃ to 400 ℃, the temperature reduction process is divided into a plurality of temperature reduction sections, the …
Four single-factor experiments were designed to determine the cement content, water-reducing agent, retarder, and methyl hydroxypropyl cellulose ether, and …
Desulfurization-gypsum-based composite cementitious materials were prepared by adding certain proportions of sulfoaluminate cement, mineral powder quick lime, retarder, and water reducer into the ...
DOI: 10.1016/j.cscm.2022.e01413 Corpus ID: 251650878; Effect of soluble phosphate, fluoride, and pH in Brazilian phosphogypsum used as setting retarder on Portland cement hydration
DOI: 10.1016/j.conbuildmat.2019.117584 Corpus ID: 212905425; Utilization of collagen protein extracted from chrome leather scraps as a set retarders in gypsum @article{Ding2020UtilizationOC, title={Utilization of collagen protein extracted from chrome leather scraps as a set retarders in gypsum}, author={Xiaoliang Ding and Sha Zhihua …
The theoretical analysis and the studies on the feasibility on the basis of a series of experiments utilizing manganese slag as retarder in stead of gypsum in cement manufacture were carried out.The results indicated that the indexes including setting time,soundness and radioactivity of portland cement measure up to the national …
It is feasible to use desulfurized gypsum as retarder of Portland cement. When the content of desulfurized gypsum after 80℃ heat treatment is 4% of Portland cement, the setting time can meet the use requirements of cement. Compared with natural gypsum, the retarding effect of desulfurized gypsum
A ternary geopolymer was designed by adding desulfurized gypsum (DG) to FA-GGBS geopolymer. Gels and ettringite-induced filling were responsible for …
ABSTRACT: This study deals with the retardation of cement setting time and workability in hot weather such as in Sultanate of Oman. Combination of sugar and gypsum was used …
Tens of millions of tons of desulfurized gypsum can be produced in China every year. Desulfurization gypsum is used as an admixture to replace part of cement in concrete. And the smaller the particle size of desulfurized gypsum, the better the mechanical properties of cement mortar. The compressive and flexural tests show that the cement mortar with …
Through experiment,the influence on the desulfurization gypsum cement mechanical performance and hydration processes was researched.The result shows that adding desulfuration gypsum instead of gypsum to cement can improve and strengthen properties of the cement.So,it can be used instead of natural gypsum to produce cement.
The obtained semi-aqueous desulfurized gypsum was the original desulfurized gypsum, which was placed in an oven at 180 °C and dehydrated for 2 h under synchronous heating with the box. The microscopic morphology of desulfurization gypsum from SEM and XRD analysis is shown in Fig. 1. The original desulfurization …
The invention discloses a desulfurized gypsum retarder, a preparation method and application thereof in sulphoaluminate cement, wherein the method comprises the following steps: the temperature of the rotary kiln is reduced from 300-400 ℃, the temperature reduction process is divided into a plurality of temperature reduction sections, …
The effects of desulfurized gypsum, heat-treated desulfurized gypsum and hydrogen peroxide modified desulfurized gypsum on the setting time of Portland cement were studied. The results showed that when the content of desulfurized gypsum after 80 °C heat treatment was 4% of Portland cement, the initial setting time was 136min, and the …
Study on desulfurized gypsum used as cement retarder ... elements of desulfurized gypsum and cement clinker. ESMA 2020 IOP Conf. Series: Earth and Environmental Science714 (2021) 032048 ...
This study deals with the retardation of cement setting time and workability in hot weather such as in Sultanate of Oman. Combination of sugar and gypsum was …