Study On The Arsenic Removal Process Of Scorodite From Lead Anode Slime

The technology of solidifying arsenic with scorodite is a kind of technical means that can effectively treat arsenic innocuously.Through this technology,the discharge of non-ferrous metallurgical wastewater and arsenic alkali slag can be reduced.At present,most of arsenic pollution comes from smelting of non-ferrous metals.When smelting lead-based non-ferrous metals,the concentrate,which contains a certain amount of arsenic,are often used to concentrate.In this way,there are about 50000 tons of arsenic continuously entering the non-ferrous smelting process every year,and finally in the form of salt and other forms,flowing into various wastes.At present,the commonly used methods of arsenic treatment are mainly fire process and wet process,etc,but in combination with these methods,arsenic is removed and solidified in the form of arsenic containing waste residue.The toxic leaching amount of arsenic containing waste residue is high,which is not suitable for long-term storage.The treatment of arsenic containing waste residue is also a problem.Research shows that there is a large amount of arsenic in scorodite,and its arsenic content can even reach 32%.Therefore,if we can use crystal scorodite to remove excess arsenic,we can achieve good treatment effect of high arsenic pollution acid.In this paper,arsenic in lead anode slime was solidified by the method of synthesizing scorodite,and the experimental parameters of each link were compared to get the best experimental conditions.The specific steps are as follows: the arsenic was put into the leaching solution through the alkali leaching of lead anode slime,and then the arsenic was precipitated in the form of sodium arsenate through cooling crystallization.The precipitated sodium arsenate reacted with iron ion to form scorodite.Through various influence conditions of alkali leaching,scorodite was synthesized.Through the change of experimental conditions,it is concluded that the best alkali leaching conditions are: the particle size of lead anode slime is-60,the temperature of alkali leaching is 90?,the leaching time is 8 hours,the stirring speed is 200r/min,the concentration of sodium hydroxide is 2mol/L,the liquid-solid ratio is 8:1,and the best arsenic leaching rate is 94.6%.In the leaching solution,4.1g sodium arsenate was precipitated and the arsenic content was 16.3%,the arsenic precipitation rate is 88.7%.The optimum conditions for the synthesis of scorodite at temperature 87?,iron arsenic ratio 2:1,reaction time 8 hours,initial reaction p H 2,and the toxic leaching amount of scorodite is 6.6mg/L.