Optimum Design And Properties Of Gypsum Foaming Agent And Foamed Gypsum

The quantity of desulphurized gypsum is increasing with the deepening of air treatment.How to realize the comprehensive utilization of desulfurized gypsum is the key to achieve energy saving,emission reduction and comprehensive environmental management.The main way to recycle desulfurization gypsum is building materials,and making it into a high-strength,light-weighted wall material is the most promising industry direction.However,the technique requires a breakthrough,which is how to reduce the density of the cast,and keep it consistent with building standards.Based on this market background and technical requirements,this paper uses the physical foaming method to prepare foamed gypsum.The effects of foaming agent composition and dispersant molecular structure on the density,cell structure and mechanics of foamed gypsum are investigated in order to Prepare lightweight high-strength gypsum wall materials that meet the needs of the building.The main results are as follows:(1)Several commercial foaming agents were used for preparing plaster foaming materials respectively,the influence of different foaming agents on foaming plaster were compared and analyzed.It has been found that the AOS was better to prepare plaster foaming materials compared with others.Its foaming ratio was 25.17 at a dosage of 0.7%.The combination of AOS with protein foaming agent and MPS improved the mechanical properties of gypsum.It was found that as the amount of foam added in the foam gypsum increases,the porosity of the gypsum increases,the density decreases,the thermal conductivity decreases,the heat retention increases,the strength decreases,and the average pore diameter increases.Porosity was inversely related to gypsum strength,and Balshin and Ryshkevitch had better correlations than the other two models.Thermal conductivity was negatively linearly related to porosity.(2)The influence of dispersant on gypsum was studied.The polycarboxylate dispersant was preferred due to electrostatic repulsion and steric repulsion,and it had better fluidity at lower dosage and improved the strength of gypsum products.The addition of PCE increased the compressive strength from 5.9 MPa to 7.1 MPa and the strength increased by nearly 20%.Residual monomers such as KEP-50,MPEG,CVPEG,and monomeric acrylic acid had different effects on the gypsum slurry.(3)As the water-paste ratio increased,the specific strength increased first and then decreased.When the water-paste ratio was 0.60,it had the highest specific strength value.The source of gypsum powder had a certain influence on the strength of the foamed gypsum,and the increase of the anhydrite component was beneficial to the improvement of the strength of the gypsum.The addition of cement and fly ash can increase the strength of the foamed gypsum.The fiber can improve the strength of the gypsum,and the recommended addition amount is about 1%.