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Calcination of Gypsum was an accidental discovery as were its rehydration characteristics. Ancient man probably used lumps of Gypsum to enclose his fire. Some degree of calcination and softening occurred and when the fire was extinguished with water he noticed the lumps soon hardened. ... The boiling temperature of 250°-260°F …
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F lue gas desulfurization gypsum (FGDG) is a synthetic gypsum that is created during the removal of SO 2 from flue gas by reacting the SO 2 with calcite (CaCO 3) to form calcium sulfite (CaSO 3 ·0.5H 2 O), which is further treated with wet limestone and forced oxidization to form calcium sulfate (CaSO 4 ·2H 2 O) (Laperche and Bigham, …
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desulfurization gypsum not easy to dehydrate, and affect the calcination temperature and quality of desulfurization gypsum. At the same time, high chloride ion content will reduce the bonding
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Figure 1: a: Gypsum crystals produced from sodium sulphate and calcium chloride; b: Natural gypsum cut along black lines; c: Gypsum crystals from a, with directions from Figure 2 marked with arrows, on side from Figure 3 marked with yellow, on cleavage plane with red; d: Crystal from a) along c-axis marked in black.
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The presence of anhydrite in calcined gypsum is caused by the technology of gypsum production, in particular, by the method of heating and by the chosen …
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This article reviews the properties, production, and applications of flue gas desulfurized gypsum (FGD gypsum) in China, a by-product of coal combustion. It also …
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The calcination-treated FGD gypsum would not influence the type and morphology hydration products of the calcium sulfur aluminate cement-fly ash-FGD gypsum system, and the calcination of FGD gypsum is able to promote the hydration degree of fly ash especially in the presence of lime, making the hardened slurry more …
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For example, it is reported that the ideal industrial temperature (solid) for the calcination of kaolinite clay is 700–850 °C, and often temperatures up to 900 °C are used in kiln calcination, with a residence time of ~ 30 min in the burning zone, to achieve near-complete calcination [70,71,72].
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Desulfurization gypsum is the product of the reaction of limestone with SO 2 in the flue gas desulfurization process. The main component is CaSO 4 ·2H 2 O [1], …
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The calcined gypsum produced by the calcination of desulfurized gypsum can be widely used in gypsum based building materials, which has great economic and socia ... 2 content on the properties of calcined gypsum were investigated, and the optimal calcination temperature and appropriate content of KAl(SO4)2 were determined. …
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The paper assesses the influence of the calcination temperature of synthetic gypsum binder 14 on the binding properties of innovative gypsum pastes, as well as on masonry and plastering mortars ...
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Automotive dyes and pigments. B. Kaur, S.N. Bhattacharya, in Handbook of Textile and Industrial Dyeing, 2011 7.4.1 Calcination. Calcination is a process of heating a substance under controlled temperature and in a controlled environment. This process is known to improve the chroma, tinctorial strength, pigmentary texture, weather stability, light …
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To determine which factor, the calcination temperature of FGD gypsum (500–800 °C), the hydration time (3–28 days) or the amount (0–2%) of the activators K2SO4 and Na2SO4, has the greatest ...
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What is Gypsum? DATE: 16-07-2007 I. Natural Gypsum A. Introduction The mineral Gypsum precipitated some 100 to 200 million years ago when sea water evaporated. From a chemical point of view it is Calcium Sulphate Dihydrate ( CaSO 4.2H 2O) deposited in sedimentary layers on the sea bed. Under high pressure and temperature Gypsum …
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Desulfurization Gypsum", and the chloride ion content was 235.66ppm. According to Table 3, the addition of 1% porous mineral material to the desulfurized gypsum had little effect on the initial setting time and the final setting time of the desulfurized gypsum slurry.The test results of mechanical
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At the same calcination temperature, the resistivity of the anode increases with the increase of the mixing ratio of calcined coke . ... How to use high temperature desulfurized coke in large quantities and avoid adverse effects on product property is an important subject in the future research of high sulfur petroleum cokes. Reference ...
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Flue gas desulfurized gypsum (FGDG) is a waste material produced in the power stations during the flue gas desulfurization process. ... FGDG is also used to produce CaS O 4 ∙ 0.5 H 2 O or CaS O 4 by calcination method [10], [11]. ... Strength properties of geopolymers derived from original and desulfurized red mud cured at ambient …
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The paper assesses the influence of the calcination temperature of synthetic gypsum binder on the binding properties of innovative gypsum pastes, as well as on masonry and plastering mortars. The calcination process of gypsum binder was carried out at four different temperatures ranging from 170 to 190 °C. The specimens for …
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The preparation of natural and synthetic gypsum prior to calcination, such as drying and grinding. The various calcination methods for β -hemihydrate and α -hemihydrate are reviewed, such as batch kettle, continuous kettle, submerged combustion kettle, conical kettle, and other calcination equipment.
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It can be seen that the dissolution rate of anhydrite in the system is lower, the cement clinker mixed with desulfurized gypsum produces more ettringite at the same hydration age, and the consumption rate of C 4 A 3 $ is slower, ... calcination temperature, and other factors in the calcination process of clinker were determined, …
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An L 9 (3 4) orthogonal experiment was carried out assess the effects of SG and/or FGDG addition on GW composting.As indicated in Table 1, the experiment included nine treatments (T1–T9), and SG or FGDG was added at three levels and alone or in combination.SG was added at 0 %, 25 %, and 45 %, and FGDG was added at 0 %, 2.5 …
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Desulfurized gypsum contains partially unreacted CaCO 3 and partially soluble salts, such as potassium salts and sodium salts. The presence of these impurities promotes the hydration process of cement. Meanwhile, these impurities can also stimulate the activity of the mixed materials, which is conducive to the development of cement strength in ...
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The furnace temperature and the residence time are important for proper SO 2 sorption: Shemwell et al. (2000) Limestone injection into furnace and activation of unreacted calcium (LIFAC) ... (Oriza sativa L.) growth and yield using desulfurized gypsum in the west of Songnen Plain, northeast China. Geoderma, 187–188 (2012), …
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Flue gas desulfurization (FGD) gypsum mainly contains gypsum, which comes from the FGD by using lime or limestone. The effects of calcining temperature …
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DOI: 10.1016/j.conbuildmat.2024.137061 Corpus ID: 270530557; Properties and microstructure of soil solidified by titanium slag-flue gas desulfurized gypsum-Portland cement composites as solidifiers
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The above research shows that the application of desulfurized gypsum in concrete systems will help improve the overall performance of concrete, realize the industrial utilization of desulfurized gypsum, and turn desulfurized gypsum into treasure, which is in line with the green and low-carbon development concept. However, adding …
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Recently, the steel slag-fly ash-desulfurized gypsum (SS-FA-DG) composite system was developed as a novel building cementitious material, however, its reaction mechanism and reaction process mains unclear. ... The effect of desulphurisation gypsum dried at different temperatures on the performance of the solid waste-based …
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1. Calcination process of desulfurized gypsum (1) Low temperature and slow calcination. Low-temperature slow-speed calcination means that the material stays in the calcination …
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The high-temperature calcination method (equipment) is that the desulfurized gypsum is in direct contact with the high-temperature flue gas for heat exchange, rapid dehydration and …
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