Papers by Keyword: Desulfurization Gypsum

Abstract: In this paper, desulfurization gypsum was made of cementing materials and expanded perlite as light aggregate, by adding the right amount of fly ash and other admixture, in the pouring forming preparation of desulfurization gypsum heat preservation material. Expanded perlite is porous surface, made its hydrophobic, lower water absorption, by emulsion coated surface of expanded perlite. In the waterproof property research, different emulsion composite waterproof contents on the influence of the bibulous rate of the product volumetric had been studied, and emulsion composite waterproof agent was chosen as the last agent with the dosage of 4%. SEM test for analyzing the microcosmic structure of desulfurization gypsum products were taken to research and analyze each combination, and discuss the waterproof and thermal insulation mechanism. The optimal parameters of the desulfurization gypsum of insulation products obtained by the experiments were: desulfurization gypsum of 90%, fly ash of 10%, and fiber of 0.5%, emulsion composite waterproof agent of 4%.

Abstract: In this paper self-leveling floor material with flue gas desulfurization (FGD) gypsum was studied. Gypsum-based self-leveling materials was prepared with desulfurization gypsum as binder and added fly ashadmixture Aadmixture B and four kinds of water reducing agents. The result indicated that HC multi-carboxylic acid based super plasticizer demonstrates excellent workability and better compatibility with gypsum, when its content was 1.0%, the fluidity of slurry met the demands of 145mm±5mm. Adding re-dispersible polymer powder to enhance the strength of desulfurization gypsum, the results showed that when its content was 3%, the adhesive strength of sample was increased to 1.21MPa that could meet the performance requirements of self-leveling floor material.

Abstract: The pot experiments were carried out to test planting of oil sunflower with the application of desulfurization gypsum in ameliorating sodic salinity soils. Results showed that exchangeable sodium pH values decreased significantly while soil salt content increased. The germination rate and yield of the sunflower increased significantly after desulfurization gypsum was applied, but excessive application of desulfurization gypsum inhibited germination and growth of the plant. There is the best improvement after application of 33.75(t·hm^-2) of desulfurization gypsum in the 0-20 cm surface layer of soils moderate in sodic salinity, such conditions are favorable for sunflower growth.

Abstract: Through this pot experiment of corns, the paper studied the effect of the use of FGD gypsum into the alkalization soil to improve corn output and soil property in the alkalization soil of the west of Jilin Province. The study indicated that FGD gypsum reduced effectively the PH value of the alkalization soil and improved the corn output. When the amount of FGD gypsum was 3t/667m², the growth index of planting corn, such as the plant height, root length, plant fresh weight, was the best. But when the amount of FGD gypsum was 2t/667m², the difference was not obvious. The results indicated that considering the factors of soil PH value and salt-resistance, when the amount of FGD gypsum was 2t/667m², the effect of the use of FGD gypsum of the alkalization soil in the west of Jilin Province to improve soil property was the best.

Abstract: The fiber of the agriculture and forestry biomass resources and the processing residues is main raw materials as a reinforcing material, the calcinated calcium sulfate hemihydrates by industrial flue gas desulfurization waste is a binder, adding efficient composite retarder to increase the initial setting time of gypsum and meet the production process requirements, adding conductive carbon black to reduce system resistance gypsum fiber to produce and meet the requirements of antistatic products. By semi-dry process, we produced the retardant, waterproof, environmental friendly and anti-static desulfurization gypsum fiberboard. Desulfurization gypsum antistatic fiberboard can meet the market demand for functional products used widely in antistatic floor, antistatic wall panel etc. The production of anti-static desulfhurization gypsum fiberboard expands the application range of desulfhurization gypsum, at the same time, which changes the structure of the forestry industry and has a positive effect on improving the forestry economic operation quality, efficiency and international competitiveness.

Abstract: In order to broaden the utilization of desulfurization gypsum in China and achieve the direct usage of desulfurization gypsum, in this paper, citric acid (CA), sodium citrate (SCA), sodium tripolyphosphate (STPP), Sodium hexametaphosphate (SP) were selected as retarder to modify desulfurization gypsum. The experiment results are as follows: the effect of SP, STPP, CA, SCA on desulfurization gypsum initial setting time is obvious; the turn is STPP> CA> SCA> SP; when the retarder dosage of STPP in desulfurization gypsum reaches 0.5%, the initial setting time can be extended to 210 min, the final setting time to 240min, which fully meets the demand of gypsum-site construction; inhibiting gypsum particles dissolution and preventing the growth of crystal nucleus are the fundamental reasons of STPP.

Abstract: The cementing material is the desulfurization gypsum. The fly ash is a admixture. A moderate amount of additive is mixed. A gypsum plaster material of micro swelling and good workability, plasticity was produced. The representative two retarders, the sodium hexametaphosphate and the citric acid, were researched. The effects of the retarders on the setting times and the mechanical properties of the desulfurization gypsum were studied. The retarding effect of the citric acid is the most prominent, but its negative impact on the flexural and compressive strength of the plaster gypsum is very large. Considering the setting time and the strength, the sodium hexametaphosphate is the best retarder of the desulfurization gypsum plaster material.

Abstract: In this paper, gypsum whiskers reinforced resin matrix composites were prepared with the desulfurization gypsum by the technology of atmospheric acidification. The influences of stabilization reagent on the stability of the gypsum whiskers were studied. Meanwhile, the enhanced effects of surface treatment and different contents of gypsum whiskers on the resin matrix composite were analyzed. Scanning electron microscopy, metallographic microscopy, X-ray diffraction test were taken to conduct analysis of the morphology and the aspect ratio of gypsum whiskers. Besides, the mechanical properties of gypsum whiskers reinforced resin matrix composites were tested, and cross-section scanning was used to analyze the strengthening mechanism.

Abstract: In order to broaden the utilization of desulfurization gypsum in China and achieve the direct usage of desulfurization gypsum, in this paper, Polycarboxylic acid water-reducer (HC), Naphthalene sulfonate formaldehyde polycondensate (NF) and Sulfonated melamine formaldehyde resin (SM) were selected as water reducer to modify desulfurization gypsum. The experiment results are as follows: SM water reducer has little effect on setting time of desulfurization gypsum, although it is helpful to increase the strength of the gypsum-sample, however, compared with HC and NF, it has no obvious effect. About HC water reducer, it has obvious effect on setting time of desulfurization gypsum, so does it to desulfurization gypsum strength, but, higher water using of normal consistency will do adverse effect on the whole with the increase of the dosage. NF water reducer has the similar effect on setting time and sample's strength on desulfurization gypsum with HC, but the dominant changes have no discipline among different mixing amounts with these two water reducer. Lower water using of normal consistency benefits the retention of the sample's strengths.

Abstract: Desulphurization gypsum-slag composite binder is a hydraulic composite binding material made by slag, desulphurization generated by coal-fired power plant flue gas desulphurization, activator and other materials. In order to study the effect of curing system on the composite binder, steam curing, autoclave curing, nature curing, standard curing and water curing were selected. The mechanical properties of desulphurization gypsum-slag composite binder were compared, and the best curing system for strength development was proposed.