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 tons of FGDG were produced in 2019, …
The decomposition kinetics of CaSO 3 was explored by thermal analysis via isothermal and non-isothermal methods [24]. However, the complex composition of SSFGDA and the high heating rate applied interfere with the decomposition reaction. Thus, the isothermal method is not conducive to studying the decomposition of CaSO 3 in desulfurized ash.
The mix proportions for cement mortar samples with different content of ISSA (0, 10 wt%, 20 wt%, and 30 wt% replacement of clinker by weight) are listed in Table 2.Among all the samples, the amount of desulfurized gypsum was 4 wt% of the binder weight, the binder-to-sand ratio was 1:3, and the water-to-cement ratio was 0.5.
The invention relates to the field of secondary pollution comprehensive treatment in iron and steel industry, and particularly to a novel system for the recovery of anaerobic thermal decomposition of desulfurized fly ash. The system comprises an induced draft fan, a high temperature reaction chamber, a solid cooling chamber, a gas cooling chamber and an …
The rapid expansion of coal-fired power plants has led to a significant increase in the production of flue gas desulfurization (FGD) gypsum, a byproduct of sulfur dioxide emission control processes [1], [2].With annual global output reaching millions of tons, FGD gypsum poses substantial environmental challenges due to its large-scale accumulation and potential …
The results showed that the addition of coke powder enhanced the thermal efficiency and reduced the decomposition ... it has a more intricate composition than desulfurized gypsum, as the sources of S originate ... 1.0 nm (secondary electrons), 2.5 nm (backscattered electrons); Acceleration voltage: 200 V-30 kV; Maximum beam current 200 nA; …
A technology for regenerated lead smelting and desulfurization gypsum, applied in chemical instruments and methods, sulfur compounds, inorganic chemistry, etc., can solve the problems of unstable operation, poor economic benefits, and high investment costs, and improve absorption efficiency, save energy, and save energy. Effects of Sulfur Resources
Red mud (RM), fly ash (FA) and desulfurized gypsum (DG) are harmful solid wastes that need to be treated. In this study, RM, FA, DG were used as the main raw materials to prepare road base ...
Request PDF | On Nov 1, 2019, Haoxin Li and others published Utilization of low-quality desulfurized ash from semi-dry flue gas desulfurization by mixing with hemihydrate gypsum | Find, read and ...
Hao et al. mixed 5 % CaO or 3 % CaO with desulfurized gypsum and calcined them at 200°C for 1.5 h or 2 h, producing Grade 3 construction gypsum. ... This is attributed to the further decomposition of gypsum and an increase in active components. ... Exothermic crystallization of sodium silicate. (2) Secondary hydration stage: Sodium silicate ...
The method comprises the following steps that: the high-sulphur coal and the dried desulfurized gypsum by mass ratio of 1 to 7-20 are added into a reducing and decomposing furnace for decomposition; a reaction temperature is controlled between 800 and 1400 DEG C; the reaction time is controlled between 0.5 and 2.5 hours; in the reaction process ...
The ultra-high addition of 20 % desulfurized gypsum is beneficial to improve the strength of DG-based binary cementitious materials with low energy consumption. ... which expedites the reaction rate and facilities the secondary hydration reaction, generating gel products such as C-S-H, C-A-S-H, etc. Currently, the water glass dosage and water ...
The invention provides a device and a method for producing II-type anhydrous gypsum from desulfurized gypsum, wherein the device comprises a drying unit, a calcining unit and a product collecting unit which are sequentially connected, the drying unit comprises a crushing device and at least one stage of drying device, and the calcining unit comprises a fluidization calcining …
To optimize the performance of GGBS-FA binary geopolymer, a ternary geopolymer was designed by the addition of desulfurization gypsum (DG). The engineering …
This study presents a method of preparing composites by adding FGD gypsum directly into epoxy resin with polyethylene-grafted maleic (PGM) anhydride as a compatibilizer of FGD gypsum/epoxy resin composites.
The invention relates to normal-temperature asphalt cement with desulfurized gypsum as a filler, which contains a filler, a curing agent and normal-temperature asphalt; the filler is a mixture of desulfurized gypsum and limestone mineral powder; the desulfurization gypsum is pretreated by high-temperature oxidation; the mass ratio of the filler to the normal-temperature asphalt is …
Provided in the present application are a system and a method for accelerating direct mineralization of flue gas carbon dioxide with desulfurized gypsum. The method comprises: absorbing carbon dioxide from a desulfurized flue gas by using ammonia water as an absorbent, so as to obtain an ammonium carbonate absorption liquid; heating a desulfurized gypsum to …
Red mud (RM), fly ash (FA) and desulfurized gypsum (DG) are harmful solid wastes that need to be treated. In this study, RM, FA, DG were used as the main raw materials to prepare road base materials based on the different (CaO + Na 2 O)/(SiO 2 +Al 2 O 3) molar ratio, and its mechanical properties, durability, microstructure and environmental performance were …
The thermal decomposition mechanism of K-feldspar with industrial waste of FGD gypsum to produce soluble potassium (K) salt was investigated. Factors affecting the recovery of K were studied.
A 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 …
The global emission of SO 2 poses a significant threat to the environment and human well-being, underscoring its utmost importance. Primarily stemming from the utilization of fossil fuels, particularly in power generation and various industrial processes such as oil refining and metal smelting [1], [2], [3], SO 2 emissions have prompted nations worldwide to implement stringent …
The invention discloses a method for preventing secondary pollution of flue gas desulfurization gypsum-improved saline-alkali land soil. The method for preventing secondary pollution of flue gas desulfurization gypsum-improved saline-alkali land soil comprises the specific steps: S1, selection of improving materials; S2, acquiring of raw materials of a microbial fertilizer; S3, …
Current study proposes an effective way to modify the properties of super-sulfated cement (SSC) paste and mortar with preheated flue gas desulfurization (FDG) gypsum at …
In this work, the mass loss of sample hydration products is mainly the dehydration of ettringite and gel, and the decomposition of calcium hydroxide and carbonate. ... Preparation, characterization and application of red mud, fly ash and desulfurized gypsum based eco-friendly road base materials. J. Clean. Prod., 284 (2021), Article 124777.
The interaction of CaS with CaSO 4 is identified as the primary secondary reaction within the intermediate product CaS. When CaSO 4 is decomposed in an atmosphere comprising 2% H 2, 20% CO ... there is no significant divergence in the surface morphologies of quicklime resulting from the reductive decomposition of desulfurized gypsum and ...
For this reason, we proposed a new technique with multi-fluidized bed and different atmospheres to decompose the gypsum into CaO and SO 2 for further utilization. The present …
The results showed that the addition of coke powder enhanced the thermal efficiency and reduced the decomposition temperature, ... CaSO 3 undergoes decomposition reactions at elevated temperatures, producing SO 2 and causing secondary environmental ... it has a more intricate composition than desulfurized gypsum, as the sources of S originate ...
Moreover, the solid waste desulfurized gypsum is used as a sulfate activator. ... And the decomposition mass of gypsum should be deducted from the total loss. Since the loss qualities of BC-modified SSC were affected by the mass loss ... vacuumed, and coated with gold. SEM images were obtained in secondary electron mode with an accelerating ...
resulting from SFGDA decomposition can be further synthesized into calcium ferrite, while the enriched SO 2 ... waste liquid and desulfurized gypsum, severely impeding its marketability and utilization. As a result, the conventional ... The prospect of secondary pollution aris-ing from the release of SO 2
CN-102976285-B chemical patent summary.
oxidized. Both gypsum and anhydrite were decomposed in a continuous manner at temperatures rang ing from 1910 to 2230°F. With temperatures of 2100°F and higher, the solids were 98 to 99% desulfur ized, and with lower temperatures, the solids were desulfurized less. However, conversion to calcium
Among them, the peaks around 90 °C are mainly the decomposition of AFt and C-S(A)-H, and the peaks around 130 °C are mainly the decomposition of DG (Chang et al., ... Preparation, characterization and application of red mud, fly ash and desulfurized gypsum based eco-friendly road base materials. J. Clean. Prod., 284 (2021), Article 124777.
The dry-process desulfurized ash that the present invention provides a kind of social spent acid of utilization prepares desulfurized gypsum method and system, includes the following steps: to mix water, dry-process desulfurized ash, stirring prepares dry-process desulfurized ash solution；Social spent acid is added in dry-process desulfurized ash solution, oxygen is …
To solve the problem of the low early strength of the fly ash-desulfurized gypsum system, this study innovatively uses sulfate to increase its early strength without shrinking late …