Its main components include desulfurized gypsum DG phosphogypsum PG and titanium gypsum TG with smaller amounts of fluorogypsum salt gypsum and others [1 2 3] CSA is a cementitious material formed through the low temperature calcination of raw materials such as limestone and gypsum and it consists mainly of anhydrous calcium
·Optimization of proportioning of desulfurized gypsum based cementitious material system based on response surface methodology ACHARA B E LIEW M influence of high temperature on microstructural damage and residual properties of nano silica
·After calcination at 120 °C the main components of FGDG are CaSO 4 ·2H 2 O and CaSO 4 ·0 5H 2 O; at this temperature dihydrate gypsum has started to partially convert into hemihydrate gypsum After calcination at 200 °C the main component is CaSO 4 · 2 O After calcination at 220 °C anhydrous gypsum is the main component of
·With the best calcination temperature of 800 °C gypsum plaster showed a relatively quick setting and maximum strength with a compact microstructure and low hydration degree due to the large
gypsum was calcined in the DRY 36 high temperature industrial furnace of Shanghai Kecheng Company The calcination system was as follows heating up from room temperature to 800 ℃ and constant temperature for 1h and then reduced to room temperature In addition the desulfurization gypsum before thermal activation and the
·Effect of curing temperature on the reaction kinetics of cementitious steel slag fly ash desulfurized gypsum composites system Author links open overlay panel Siyu Duan a Hao Wu a and the time of fifth stage was >30 h and >28 h respectively Thus increases in temperature shortened the reaction times of each stage that is increasing the
The type of desulfurized gypsum is greatly affected by temperature The desulfurized gypsum loses crystal water from 135 °C and all the crystal water is removed at 185 °C When the calcination temperature is 1250 1300 °C 4CaO·2Si 2 O 2 ·CaSO 2 disappears and decomposes into α 2CaO·SiO 2 and free CaSO 4
·Factors including sludge ash mixing ratio and calcination temperature affecting the properties and microstructure of the mixed calcinated sludge ash MCSA and cement paste were analyzed
·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 FGD gypsum
·In the limestone gypsum flue gas desulfurization process ton of desulfurized gypsum can be generated for each 1 ton of SO 2 removed A 300 MW coal fired thermal power unit discharges about 30 000 ton of desulfurized gypsum every year assuming % sulfur in coal A substantial amount of desulfurized gypsum is generated as a by product
·The calcination temperature of kaolinitic clays was investigated to optimize the reactivity of calcined clay Batches of a clay with 50% kaolinite were calcined in an oven at five different calcination temperatures from 600 to 850°C An example is shown in Figure 8 where different gypsum additions in addition to the amount in the cement
·Fig 9 c indicates that with a RM content of 30% the optimal calcination temperature remains 800 °C achieving compressive strengths of and MPa at 3d 7d and 28d respectively In summary with a calcination temperature of 800 °C and a RM content of 10% the compressive strength of the RM cement mortar is the highest
·The calcination treated FGD gypsum would not influence the type and morphology hydration products of the calcium sulfur aluminate cement The decomposition of chemical bound water of gypsum can occur when the temperature is higher than 120 °C and the two molecular H 2 O can be released The desulfurized gypsum also dissolved
·FGD gypsum can be made into desulfurized construction gypsum and high strength gypsum after the calcination process It is mainly used in the production of stucco plaster plasterboards paper faced gypsum board gypsum blocks and other production [[4] [5] [6] [7]] In addition gypsum is also directly used as road base filling material such as highway and
·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
·In this investigation non spontaneous combustion coal gangue was activated by two methods 1 low temperature calcination and 2 calcium addition Differences in the activity of the activated coal gangue were studied at various calcination temperatures and amounts of calcium addition Meanwhile the cementation activity of the activated coal gangue was
For the production of LC 3 grinding may be used to obtain a uniform and intimate mixture with clinker limestone and gypsum [92 119] The cement can also be produced by blending components after separate grinding Ferreiro S et al 2019 Influence of fineness of raw clay and calcination temperature on the performance of calcined clay
Desulfurized gypsum gypsum powder ：1 Setting time Initial setting ≥8min final setting ≤30min Fineness ≤5% Strength（MPa） 2 hours bending resistance ≥ compressive strength ≥; Three phase control Dihydrous gypsum is less than 3% semi hydrous gypsum is more than 84% soluble anhydrous gypsum is less than 3%;
·Prepared from Desulfurized Gypsum with High Chloride Ion Content Yin Dongjie Wu Fade Wang Ying Wang Pengqi Tan Danjun Jian Ming and and affect the calcination temperature and quality of desulfurization gypsum At the same time high chloride ion content will reduce the bonding put it in a constant temperature water bath at 100°C
·FGD gypsum can be made into desulfurized construction gypsum and high strength gypsum after the calcination process It is mainly used in the production of stucco plaster plasterboards paper faced gypsum board gypsum blocks and other production [[4] [5] [6] [7]] In addition gypsum is also directly used as road base filling material such as highway and
·To sum up calcination achieved better purification results and improved the properties of gypsum plaster [24 28] Further the phase transformation of PG and harmful impurities are related to the calcination temperature [24 36] Moreover it may be noted that as in many published studies impurity is the main factor affecting the properties of the plaster [37 38]
·The optimal calcination temperature for RM was 800 °C with an optimal addition amount of 10% The compressive strengths of RM cement mortar at 3 7 and 28d with optimal conditions are and MPa respectively showing increases of and times over untreated RM cement mortar desulfurized gypsum etc as
·The predicted histories of heat flux and surface temperature from FDS have been used as boundary conditions to predict the depth of calcination of the gypsum board using a validated in house one
·Study on desulfurized gypsum used as cement retarder Jianmei Zhou School of Chemistry and Chemical Engineering Inner Mongolia University of Dry the desulfurized gypsum under normal temperature and use it for standby after grinding The desulfurized gypsum is heat treated at 50℃ 80℃ and 110℃ respectively After grinding it is mixed
