Preparation Of Gypsum Mold Box By Solidifying Waste Incineration Fly Ash With Phosphorus Building Plaste

Phosphogypsum is a solid waste produced in the process of wet-process phosphoric acid.A large amount of accumulated phosphogypsum not only occupies land,but also pollutes the surrounding environment.Therefore,the resource utilization of phosphogypsum is particularly important.At present,phosphogypsum is a new way to expand the utilization of phosphogypsum as a resource.However,phosphogypsum contains a small number of fluorine compounds,acid-insoluble substances,iron-aluminum compounds,and other impurities,which is extremely detrimental to the development of its building materials resources.With the wide application of domestic waste incineration technology in China,the amount of fly ash produced by the incineration of waste is increasing year by year.China because it contains heavy metals with high leaching concentrations and highly toxic and refractory dioxins.How to treat MSW incineration fly ash safely and effectively has become an urgent environmental and social problem.In order to deal with the environmental pollution caused by the treatment and disposal of solid waste phosphogypsum and waste incineration fly ash,the subject uses a simple comparison method to study the preparation of gypsum mold box from phosphogypsum solidified fly ash through specific experimental operations.At the same time,improve the efficiency of comprehensive utilization of the two kinds of solid wastes to achieve sustainable development.The main contents and results of the project are as follows:This paper analyzes the factors that affect the fly ash from the self-cementation waste incineration of phosphogypsum building.This paper studies the influence of the change of fly ash dosage,water dosage,quartz sand dosage,before and after washing,Na Cl,KCl dosage,Ca（OH）₂ dosage,and other factors on the standard consistency water demand,setting time and 2h strength of the solidified body by simple comparison method.The results show that:（1）with the addition of fly ash,the void of the solidified body will increase,which will increase the water demand for standard consistency of solidified body,prolong the setting time,and the strength will first decrease significantly,and then increase to 9%,and then stabilize;（2）In the waste incineration fly ash,the main soluble components are Na Cl and KCl.With the addition of Na Cl and KCl,the performance of the solidified body will be reduced,but the degree of reduction is much smaller than that of the fly ash,so the soluble components are not the main cause;（3）With the addition of Ca（OH）₂,the insoluble Ca（OH）₂ has a greater impact.Then,after the addition of Na Cl,KCl,Ca Cl₂,Na OH and Ca（OH）₂,it is found that the particularity of Ca（OH）₂ is caused by OH^-.Therefore,the final conclusion is drawn that OH^-,KCl,and Na Cl are the main factors that affect the performance of the curing body.The experiment also found that when the dosage of Ca（OH）₂ is small,the effect on the solidified body is OH^-.When the dosage of Ca（OH）₂ is more than 2%,it is because of the effect of Ca（OH）₂’s own gelation.The performance process of the phosphogypsum-fly ash solidified body is studied.This paper hopes to design a new process by adding a coagulant,water-reducing agent,glass fiber,chelating agent,and other additives on the water requirement of standard consistency,setting time,and 2h strength of phosphogypsum-fly ash solidified body.The results showed that:（1）Through comparison of potassium sulfate,sodium sulfate,Na₂Si O₃,Na OH and other coagulants;Through comprehensive comparison,it is found that sodium sulfate is suitable and effective.With the increase of water demand of sodium sulfate,the setting time is shortened.When adding 2.0%,it meets the setting time required by the factory,so the best dosage is 2.0%.（2）Through the screening of polycarboxylic acid series,naphthalene series and melamine series water-reducing agents,the results show that the water-reducing effect of polycarboxylic acid series>naphthalene series>melamine series,naphthalene series and melamine series have no obvious effect on the strength,but the polycarboxylic acid series has greatly improved the strength,and the final dosage is 0.2%.（3）To prepare a gypsum mold box,a new process flow is designed:First chelating is to use a chelating agent to treat stable fly ash first.The chelating agent has a high removal rate of fly ash pollutants,The best dosage of a chelating agent is 3%and meets the standard requirements,and has no negative impact on the parameters of the solidified body.After curing with various admixtures,the optimal ratio was found to be chelating agent 3%,coagulant 2.0%,water reducer 0.2%,and glass fiber 0.5%.