Study On Modification Of Titanium Gypsum Of Panxi Area In New Building Materials

Titanium gypsum?TG?,titanium slag powder?TSP?,and flue gas desulfurization gypsum?FGD?are the three major industrial solid wastes of the titanium industry in Panxi,causing harm to the ecological environment in Panxi.Increased corporate environmental pressure.In order to alleviate the impact of TG and TSP on the environment and the resource of TG,this paper proposes two solutions:?1?using TG and FGD to make composite gypsum,and then adding gypsum reinforcement?the main component is polycarboxylic acid ether?to further increase the strength of composite gypsum.?2?With the goal of maximizing the use of TG,a comprehensive use of three industrial solid wastes,combined with cement and gypsum reinforcement,to produce TG-based composite cementitious building materials.The following conclusions were reached:Calcining can increase the strength of TG.The suitable calcination temperature and time of TG in Panxi area are:190°C for 2h,and the flexural and compressive strength of 2h reaches0.83 MPa and 1.91 MPa.According to XRD analysis,the degree of crystallization of TG in Panxi area after calcination at 190°C for 2h was 77.17%,and the degree of crystallization was not 1,which proved that some impurities in TG crystallized.When the FGD content is 45%,the strength grade of TG reaches 1.6 grade of"Building Gypsum"?GB/T 9776-2008?.With the increase of FGD content,the water consumption of TG standard consistency gradually decreases,and the initial and final setting time increase.The Cubic?x,A,B,C,D?model can better predict the change of flexural strength and compressive strength of TG test blocks,and the LangmuirEXT2 function model can better predict the change of moisture content of TG test blocks.With the increase of Fe?OH?₃ content,the effect of gypsum enhancer on improving the mechanical properties of TG decreases significantly.The appropriate amount of gypsum enhancer is 0.09%.The 2h flexural and compressive strength of TG-FGD composite gypsum is1.83 MPa and 3.89 MPa,which has reached the 1.6 grade of"Building Gypsum"?GB/T9776-2008?.Gypsum enhancer reduces the standard consistency water consumption of TG and increases the strength of TG test block.Fe?OH?₃ will hinder the development of dihydrate gypsum crystals in TG,resulting in a decrease in the strength of TG.The strength of TG-based composite cementitious building materials test blocks tends to increase first and then decrease as the cement content increases.The strength of TG-based composite cementitious building materials for 2h decreases with the increase of the amount of TSP.The suitable ratio of TG-based composite cementitious building materials is:TG:FGD:cement:TSP=12:8:1:4.On this basis,the strength of TG-based composite cementitious building materials increases with the increase of the amount of gypsum enhancer.When the content of gypsum reinforcing agent is 0.27%,the TG-based composite cementitious building material has a flexural strength of 2.09 MPa and 5.81 MPa in 2 hours,an initial setting time of 5minutes,and a final setting time of 16 minutes,reaching"Building Gypsum"?GB/T 9776-2008?2.0 grade.According to XRD and SEM analysis,the strength of TG-based composite cementitious building materials is mainly provided by CaSO₄·2H₂O crystals produced by CaSO₄·0.5H₂O hydration.Part of the unhydrated TSP will be embedded in CaSO₄·2H₂O crystals.Adding cement produces ettringite and calcium aluminum carbonate compounds,which further improves the strength of TG-based composite cementitious building materials.The use of gypsum enhancer to improve the strength of TG-based composite cementitious building materials can avoid the"frost"problem caused by alkaline activators such as lime,which is conducive to promoting the engineering application of TG.