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In this study, the potential of using desulfurized gypsum (DG), phosphogypsum (PG), gypsum dihydrate (G), and calcium carbide slag (CS) in the production of supersulfated cement (SSC) was investigated. The effects of various types of gypsum and their dosages on the performance and hydration process of SSC were thoroughly examined.
WhatsApp: +86 18221755073Tens 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 3% and 4% …
WhatsApp: +86 18221755073The results show that adding desulfurized gypsum, which accounts for 6% to 8% of the total mass of the cementitious material, has no adverse effect on the workability and can significantly...
WhatsApp: +86 18221755073when the amount of cement is 18%, the softening coefficient of desulfurized building gypsum is 0.71, and the water resistance is better[5]. Research by Butakova et al. found that adding a certain amount of cement and silica fume into gypsum can improve its water resistance, and the softening coefficient has been increased from 0.33 to 0.50[6].
WhatsApp: +86 18221755073The semi-hydrate content of desulfurized gypsum is adjusted as a natural plaster substitute for producing gypsum board, wallboard [107].The modified treatment of desulfurized gypsum with cement, inorganic waste, straw fiber and other wastes can be used to manufacture high-insulation and compression-resistant wall materials [108].Desulfurized gypsum is incorporated into the …
WhatsApp: +86 18221755073The main utilization method of FGD gypsum is still used in construction materials (Ye et al., 2019). As an auxiliary material or instead of natural gypsum, it can be widely used in concrete, walls, concrete, etc. It is the best way to use desulfurized gypsum in large quantities, but its economic value is relatively low (Pedreno-Rojas et al., 2020).
WhatsApp: +86 18221755073Also, it will produce a mix with good workability for a longer time. Adding gypsum should be limited to a certain level. The European code stipulates the dosage of SO3 to 3.5-4% of the cement mass. Adding more gypsum …
WhatsApp: +86 18221755073The production of cement is a highly energy-intensive process, which consumes 3.0 % of the world's annual energy output and releases roughly 8.0 % of the global CO 2 emissions [1], [2], [3].To meet the carbon neutral goal and alleviate global energy crisis, developing a green and low-carbon approach for cement production is urgently required.
WhatsApp: +86 18221755073Li et al. [12] showed that by adding desulfurized gypsum to concrete with a large amount of slag, the loss rate of early compressive strength of concrete was improved, the hydration reaction rate ...
WhatsApp: +86 18221755073Magnesium oxychloride cement (MOC) prepared by using magnesium chloride and light calcined magnesia has been widely used as decorative materials, refractory materials and adsorbing materials.
WhatsApp: +86 18221755073In this study, desulfurized building gypsum was modified by adding different amounts of 42.5R ordinary Portland cement to prepare qualified GSL. The mechanism of different cement content was systematically studied through experimental test and theoretical analysis.
WhatsApp: +86 18221755073Concrete/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 solubility when ...
WhatsApp: +86 18221755073Tens 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.
WhatsApp: +86 18221755073The results show that adding desulfurized gypsum, which accounts for 6% to 8% of the total mass of the cementitious material, has no adverse effect on the workability and can significantly improve ...
WhatsApp: +86 18221755073A comparison between Fig. 12 (III) and Fig. 12 (VI) reveals that the presence of cement improves the heat release performance of A1 (PO is obtained by adding a small amount of cement to A1). Compared to A1, cement introduces additional C 3 S, C 2 S, C 3 A, and C 4 AF, accelerating the formation of hydration products and dissolution of reactants.
WhatsApp: +86 18221755073In order to explore the influence of the types of waste gypsum on the properties of alkali slag cement, fluorogypsum (FG) and flue-gas desulfurization (FGD) gypsum were comparatively investigated. Moreover, the action mechanisms of FG and FGD gypsum on the properties of alkali slag cement were analyzed. The results show that both the FG and FGD …
WhatsApp: +86 18221755073The main hydrate phase C 4 A 3 S̄ in BSAC has a very fast hydration rate, and most of them complete the release of hydration heat in 2–12 h [20]. The main hydration products of BSAC are ettringite (AFt), monosulfide calcium sulphoaluminate hydrate (AFm) and amorphous aluminum hydroxide (AH 3).These hydration products make the microstructure of cement …
WhatsApp: +86 18221755073Desulfurization gypsum, also known as FGD gypsum (flue gas desulfurization gypsum), is an industrial by-product gypsum obtained by desulfurization and purification of flue gas generated after combustion of sulfur-containing fuel (coal, oil, etc.), and its composition is calcium sulfate … See more
WhatsApp: +86 18221755073The compressive strength of the modified cement was significantly improved by adding fly ash to MOSC [21]. Wu et al., (2015) [22] found that the compressive strength of cement could be increased to 80 MP after 28 days of curing by adding 0.5 wt% phosphoric acid or potassium dihydrogen phosphate by weight of magnesium oxide to MOSC. In addition ...
WhatsApp: +86 18221755073Cement 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+ rapidly. When these ions ...
WhatsApp: +86 18221755073The 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 ...
WhatsApp: +86 18221755073A method for co-producing sulphoaluminate cement and sulfur by using desulfurized gypsum and aluminum ash, comprising: (1) drying aluminum ash, and heating desulfurized gypsum for dehydration to obtain semi-hydrated gypsum; (2) mixing the aluminum ash with the semi-hydrated gypsum according to a preset ratio, pulverizing, and homogenizing; (3) calcining the pulverized …
WhatsApp: +86 18221755073An innovative approach suggests using titanium slag and flue gas desulfurized gypsum as substitutes for Portland cement for soil solidification. This study systematically evaluates the effects of titanium slag-flue gas desulfurized gypsum-Portland cement composite (TS-FGD-OPC composite) solidifier on the performance of solidified soils.
WhatsApp: +86 18221755073The utilization of desulfurized building gypsum as raw material for gypsum-based self-leveling mortar (GSL) is limited by its low strength and poor water resistance. The objective of this study was to improve. comprehensive properties of GSL and prepare qualied desulfurized building gypsum-based self-leveling
WhatsApp: +86 18221755073In this paper, coal gangue, carbide slag and desulfurized gypsum (DG) were used as raw materials to calcine the all-solid-waste-based belite sulphoaluminate cement (BSAC), …
WhatsApp: +86 18221755073When water is mixed with cement illuminates and sulfates get to react and evolve some heat but gypsum acts as a coolant and brings down the heat of hydration. Gypsum helps to increase the time for concreting activities like mixing, placing, …
WhatsApp: +86 18221755073Flue 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 ...
WhatsApp: +86 18221755073the 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-product
WhatsApp: +86 18221755073The main purpose of adding gypsum in the cement is to slow down the hydration process of cement once it is mixed with water. The process involved in hydration of cement is that, when the water is added into cement, it starts reacting with …
WhatsApp: +86 18221755073The utilization of desulfurized building gypsum as raw material for gypsum-based self-leveling mortar (GSL) is limited by its low strength and poor water resistance. ... crystal morphology, and pore structure were also analyzed. Cement significantly improved the fluidity of slurry. Moreover, the compressive strength and softening coefficient of ...
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