Study On The Preparation Of Copper Slag-based Oxalate Chemically Activated Cementitious Material And Its Solidification Of Acid Arsenic Slag

Copper slag is the metal slag produced during the pyrometallurgical smelting process of copper.The arsenic iron slag is the arsenic-containing waste slag produced by the treatment of arsenic-containing wastewater.With the increase of metal smelting,the output of copper slag and arsenic iron slag also increases year by year.The process of treating copper slag and arsenic iron slag is complicated and costly.Most of them are stored in a way that will cause irreversible damage to the environment.In this paper,copper slag based oxalate chemically activated gelling material is prepared by copper slag and applied to solidify arsenic iron slag,which provides a copper slag utilization mode and harmless treatment of arsenic iron slag.It has been found that the copper slag-based oxalate chemically excited gelling material has a good curing effect on heavy metals contained in copper slag,avoids environmental pollution,and under acidic and chemical stability,it is resistant to acidic arsenic and iron slag.It has a good curing effect and achieves the effect of treating waste.In this paper,the effects of different ratios on the setting time,compressive strength and toxic leaching concentration of arsenic on 7 d and 28 d were investigated by single factor experiments.The results are as follows:?1?The Fe content in copper slag accounts for 37.123%,and Si accounts for13.095%.Fe mainly exists in the form of magnetite?Fe₃O₄?and fayalite?Fe₂SiO₄?,and the Fe content in arsenic iron slag accounts for 23.945wt%.As content accounts for 27.048wt%,mainly in the form of topostone?Fe₄?OH?₄?AsO₄?₃H·5H₂O??FeAsO₄ and amorphous phase.?2?The optimum ratio of oxalate chemically excited gelling materials was obtained by single factor experiment:m?CS?/m?OA?value was 100/25,W/C was 0.17,boric acid dosage was 2.5wt%is the best ratio.The initial setting time of the copper-based oxalate chemically-activated cementitious material obtained by the non-admixed retarder was 17 min,and the average compressive strength at 3 d,7 d,and 28 d were 26.1 MPa,31.4 MPa,and 33.6 MPa,respectively.The coagulation time of the copper slag-based oxalate chemically excited cementitious material obtained by adding the retardant boric acid was 29 min,and the compressive strengths at 3 d,7d,and 28 d were 23.2 MPa,28.9 MPa,and 38.5 MPa.?3?Preparation of copper slag-based oxalate chemically-activated cementitious material is not suitable for curing arsenic iron slag.Therefore,the optimum curing ratio is determined by single factor test:m?CS?/m?OA?is 100/15,W/C is 0.18⁰.20,the optimum solid capacity of arsenic iron slag is 70wt%¹00wt%,and when the content of arsenic iron slag is 70wt%,the setting time is 19 min,3 The compressive strengths of 3 d,7 d and 28 d were 7.9,11.8 and 11.4 MPa,respectively.The toxic leaching concentrations of arsenic at 7 d and 28 d were 2.20 mg/L and 2.32 mg/L.?4?According to SEM-EDS,FT-IR and XRD analysis,the main hydration products in the copper slag-based oxalate chemically excited cementitious materials are FeC₂O₄·2H₂O,FeC₂O₄·2H₂O The dissolved Fe²⁺and the adjacent two C₂O₄^2-form a coordination compound,which is a macromolecule having an infinite chain structure.The main hydration products of solidified acidic arsenic iron slag are FeC₂O₄·2H₂O,Fe₄?OH?₄?AsO₄?₃H·5H₂OandNa₂Fe₄?OH?₅?AsO₄?₃·7H₂O,m?CS?/m?OA?value has a greater impact on hydration products...