| In this paper,studide on arsenic waste residue produced in yunnan,studied its leaching characteristics of arsenic toxicity under different environment;Through multi-factor orthogonal experiments and single factor experiment to study the dosage of phosphorous slag,fly ash and other materials,and the variety of chemical admixtures and content on the polymer materials,the preparation of the excellent mechanical properties of polymer materials;By using phosphorus slag-fly ash base polymer material curing arsenic waste residue,examines mechanical properties and arsenic leaching characteristics of the arsenic waste residue solidified body in different curing condition;Through the freeze-thaw experiment,sulfate erosion experiment preliminary exploration to the durability of polymer material solidified body.Studies shows that:(1)The leaching concentration of arsenic residue was relatively large in different pH,and relatively stable in neutral environment,but still more than1000mg·L-2.The additive lime can effectively control the leaching concentrations of arsenic residue,but still has poor durability of arsenic residue after lime treatment.In the natural environment,extremely easy to cause secondary pollution;It can be seen that the dosage of water glass was too high,would cause the increase of arsenic leaching concentration by the influence of adding water glass on the solidified body.(2)Finally confirmed the content of phosphorus slag75%,fly ash 15%and high calcium ash 10%,and water glass of chemical admixtures module for M=1.2,the content was 4%,the mechanical properties of material was the best,atmospheric pressure steam curing 24h,the compressive strength of 40.98MPa.The methods XRD,FTIR and SEM were used to analyze the arsenic residue and geopolymer material,The main phase composition as amorphous phase,has rich mesh structure.(3)Through the analysis of arsenic waste residue,the main composition are As2O3 and CaF2,arsenic content was 14.2%.The leaching toxicity of arsenic characteristics under different pH is reviewed,its lowest arsenic leaching concentration of 1350 mg·L-1,belong to the hazardous waste.Using the polymer material of phosphorus slag to solidify process,examines the influence of performance of the solidified body by curing time and way,dosage of arsenic residue.The best maintenance way for steam curing,curing time is 32h,arsenic residue content is 34%,the largest compressive strength of the solidified body is 13.6MPa,arsenic toxicity leaching concentration is 2.4 mg·L-1,lower than the national standard limit(5mg·L-1).(4)Through the analysis of XRD,FT-IR and SEM,The geopolymer has difficult soluble salt formation such as Ca3(AsO4)2、Ca2As2O7、AlAsO4、Ca10Si7As18 so on after solidified.Arsenic mainly existed in the form of undissolved salt,fill in the abundance of mesh structure of polymer materials.Thus through physical packages and chemically bonded forms of stabilization treatment of arsenic waste residue.(5)Freezing and Sulfate attack,Solidified body quality has changed little after freezing and thawing through three methods.After 15 cycles the compressive strength of solidified body can still 15MPa;At the same time,toxicity leaching of arsenic compounds increasing with rising of number of freeze-thaw damage,after 9 circulation exceeds the national standard.At the same time,the toxic leaching of arsenic compounds increased with freeze-thaw damage,and above the national standard after 9 cycles.With the increase of the number of erosion compressive strength of solidified body down,but is still greater than 25MPa after 8 cycles,arsenic leaching concentration increased,the trend was not obvious,and reach the national standard in the former 5 cycles.(6)Solidified body economic cost analysis:with phosphorus slag base polymer material solidified 35000 tons arsenic waste residue of the raw material cost is RMB 9.9485 million every year,processing and manufacturing cost is RMB 3.51375 million every year,solidified cost is reasonable. |
