Research On The New Technology And Mechanism Of Tungsten Smelting Slag To Purify Tungsten Smelting Wastewater

At present,the scheelite and wolframite mixture ore is mainly processed by the high pressure alkali decomposition-ion exchange process.The tungsten smelting residue produced during the smelting process is often discarded due to its low tungsten content,which causing environmental pollution.The concentration of fluorine,phosphorus and arsenic in acidic wastewater is far higher than the industrial wastewater discharge standard,fractional precipitation is often used to deal with the wastewater,which need to consume a large amount of precipitation reagents,the processing procedures are complicated,and the cost is high.Aim at the above problem,a novel method to purify fluoride,phosphorus and arsenic in tungsten smelting wastewater with tungsten smelting residue was proposed,and the new process and related basic theories were researched.The specific contents are as follows:?1?The exploration experiments of tungsten smelting residue purified tungsten smelting wastewater have shown that:by controlling certain reaction conditions,tungsten smelting residue could effectively remove fluorine,phosphorus and arsenic in wastewater.Through process research,to determine the better process conditions to meet the industrial wastewater discharge standards:the amount of tungsten smelting residue 25g,reaction time 30min,stirring speed 400rpm,reaction temperature 30°C,the initial pH of wastewater 3.42,under this condition,the concentration of fluorine,phosphorus and arsenic in wastewater was reduced to 9.589ppm,0.0342ppm and 0.0274ppm.Through the adaptability research between new process and ambient temperature,the functional relationship between residue dosage and room temperature under different room temperature conditions was established:y=56.08929-1.61071x+0.0169x²Tungsten smelting enterprises can use this function to determine the amount of residue at different room temperature of 5-40?,so as to make the wastewater discharge to the standard,so as to make the wastewater can be discharged up to the standard and facilitate the practical operation of enterprise.?2?Due to the composition and crystal form of tungsten smelting residue are complex and it is difficult to detect and characterize,so as the elements conservation to speculate the possible substances in residue,and then used pure substances instead of possible components to conduct experimental research,and found that the effect of the Ca₅?PO₄?₃OH removing fluorine,Fe?OH?₃ removing phosphorus and arsenic,MnO₂ removing phosphorus and arsenic were the best.Base on this,the conditions and rules of using the 3 matter to remove fluorine,phosphorus and arsenic in wastewaters were studied,that confirmed the smelting residue must contained Ca₅?PO₄?₃OH which was the main substance for removing fluoride in wastewater,and metasomatism and double decomposition were occurred during the fluoride removal process of wastewater.Removal of phosphorus and arsenic in wastewater were the result of coprecipitation of various iron salts and manganese salts,and the residue at least contained one of the Fe?OH?₃ and MnO₂,which plays a major role in removing phosphorus and arsenic from wastewater.?3?The kinetics results of removing fluorine,phosphorus and arsenic from wastewater by tungsten smelting residue waste water were shown:the adsorption behavior of fluorine in wastewater by tungsten smelting residue conformed to the Langmuir isotherm model and met the pseudo-second-order kinetic model.It was an adsorption process of spontaneous,entropy-increasing,endothermic,and mainly based on chemisorption;the adsorption behavior of phosphorus and arsenic in wastewater by tungsten smelting residue was in accordance with the Freundlich model and met the pseudo-second-order kinetic model.It was an adsorption process of spontaneous,entropy-increasing,endothermic,and mainly based on chemisorption.