Study On The Acid Leaching Of Arsenic,Antimony And Bismuth By Copper Anode Slime And The Hydrolysis Mechanism Of Antimony And Bismuth

Copper anode slime is a by-product produced in the process of refined copper,which usually contains Au,Ag,Se,Te,Pb,Cu,As,Sb,Bi,Ni,Sn,SiO₂,Al₂O₃,and platinum group metals,etc.Therefore,copper anode slime is an indispensable and important raw material for the extraction of rare and precious metals.This paper takes the nine elements of Au,Ag,Cu,Pb,As,Sb,Bi,Se,and Te in copper anode slime as the research objects,and conducts mineralogical research on the raw materials of copper anode slime and acid leaching slag to clarify Au,Ag,Cu,Pb,As,Sb,Bi,Se,Te nine elements before and after the composite acid leaching state and content changes.The results show that most of Au,Ag,Pb and Se remain in the composite acid leaching residue,Cu,As,Sb,Bi and Te enter the acid leaching solution and the rare precious metals are effectively separated.Through XRD,XRF,ICP,SEM,EDS and other methods analysis of copper anode slime as it is,it can be seen that Cu in copper anode slime raw material mainly exists in the form of Cu_xS_y,etc.Se and Ag mainly in copper anode slime,it exists in the form of AgCl and Ag₂Se;Te and Sb mainly exist in the form of oxide;Au,As,Bi,and Pb mainly exist in the form of element,oxide,sulfate,etc.Cu in composite acid leaching residue mainly exists in the form of Cu₇S₄;As and Bi contents are extremely low,almost all enter the acid leaching solution,so it is difficult to detect in acid leaching residue;Ag mainly exists in acid leaching residue in the form of AgCl;Te and Sb are low in acid leaching slag,the residual Te and Sb mainly exist in the form of acid radicals;Au in acid leaching slag mainly exists in elemental form;Pb mainly exists in the form of PbSO₄.The copper anode slime was subsequently treated with a single hydrochloric acid,sulfuric acid,and sodium chloride system,as well as a hydrochloric acid-sodium chloride,sulfuric acid-sodium chloride,and hydrochloric acid-sulfuric acid system.The results showed that in the unit system and binary system,the No effective separation can be obtained;in order to find an effective environmentally friendly leaching agent for the effective separation of rare and precious metals,a composite acid leaching agent（hydrochloric acid-sulfuric acid-sodium chloride）is used in this article,and arsenic,antimony,and bismuth are used as research objects.The effect of different conditions on the leaching effect of arsenic,antimony,bismuth,and finally reached:when the complex acid leaching has a chloride ion concentration of 6 mol/L,a hydrogen ion concentration of 6 mol/L,a heating temperature of 60°C,and a stirring time of 3h,ultrasonic time of 1.5 h,and solid-liquid ratio of 1:9,The leaching rates of arsenic,antimony and bismuth were as high as 90.46%,88.95%and 85.68%,respectively.The density functional method was used to explore the hydrolysis mechanism of antimony and bismuth.The thermodynamic calculations of the energy,state density,number of charge layouts,number of overlapping populations,Sb hydrolysis and Bi hydrolysis of antimony and bismuth compounds were combined with experiments.Exploring the transfer path of antimony and bismuth atoms in trivalent antimony and bismuth in water system,ethanol system and ethylene glycol system,The results show that thermodynamic calculation and analysis of antimony and bismuth hydrolysis pH of 2 and 4,respectively,can better hydrolyze Sb³⁺and Bi³⁺to their corresponding oxychloride;and there are two main ways to hydrolyze SbCl₃ to oxychloride:namely,water and alcohol ionized hydroxyl groups replace one Cl atom in SbCl₃to form[Sb（OH）Cl₂]monomer,with the intensified degree of hydrolysis removes H and Cl atoms to form SbOCl,Sb₃O₄Cl,Sb₄O₅Cl₂;or Sb atoms directly form OH with ionized water and alcohol[Sb—OH]monomer,and Cl atoms replace the hydroxyl group in[Sb—OH]monomer,the H atoms on the direct formation of SbOCl,Sb₃O₄Cl,Sb₄O₅Cl₂.There are also two main ways to hydrolyze BiCl₃ into oxychloride:one is that the[Bi—Cl]ionic bond between BiCl₃ is broken,and the hydroxide radical replaces the chlorine atom to form Bi（OH）₂Cl,Bi（OH）₂Cl is in the aqueous solution is extremely unstable,and it is easy to continue to hydrolyze.The two hydroxyl groups contained in it are easy to combine with each other and lose a part of the water,or the hydroxyl group contained in Bi（OH）₂Cl is easy to react with H⁺in the aqueous solution,lose a part of the water and participate.The number of reacted Bi（OH）₂Cl reactions determines the degree and complexity of the production of a series of bismuth oxychloride compounds（BixOyClz）;the other is that bismuth atoms easily form[Bi—OH]monomers with hydroxyl groups,chlorine,the atom replaces the hydrogen atom on the hydroxyl group in the[Bi—OH]monomer to directly form BiOCl.Infrared spectroscopy proves that SbCl₃ and BiCl₃ are red-shifted and blue-shifted in both water and alcohol hydroxyl groups;the hydroxyl group located in the high-wave region vibrates because the chlorine atom replaces the hydrogen atom,which increases the electron cloud density and force constant.As k increases,an induction effect occurs,the group frequency shifts to a high wave number,and the infrared spectrum shifts red;and—OCl is relatively less polar than—OH,so the hydroxyl vibration at the low peak shifts to the low peak and occurs.The blue shift proves that the hydrogen atom on—OH is replaced by a chlorine atom,which is consistent with the calculation result of the strength of the covalent bond between chlorine and oxygen,and then proves the calculation result of density functional method.