Interaction mechanism of cyanide with pyrite during the cyanidation of pyrite and the decyanation of pyrite cyanide residues by chemical oxidation  

作　　者：Wenwen Han Hongying Yang Linlin Tong 

机构地区：[1]Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education),Northeastern University,Shenyang 110819,China [2]School of Metallurgy,Northeastern University,Shenyang 110819,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第9期1996-2005,共10页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.52274348);the Major projects for the“Revealed Top”Science and Technology of Liaoning Province,China(No.2022JH1/10400024);the National Key Research and Development Program of China(No.2018YFC1902002).

摘　　要：The toxic cyanides in cyanide residues produced from cyanidation process for gold extraction are harmful to the environment.Pyrite is one of the main minerals existing in cyanide residues.In this work,the interaction of cyanide with pyrite and the decyanation of pyrite cyanide residue were analyzed.Results revealed that high pH value,high cyanide concentration,and high pyrite dosage promoted the interaction of cyanide with pyrite.The cyanidation of pyrite was pseudo-second-order with respect to cyanide.The decyanation of pyrite cyanide residue by Na_(2)SO_(3)/air oxidation was performed.The cyanide removal efficiency was 83.9% after 1 h of reaction time under the optimal conditions of pH value of 11.2,SO_(3)^(2-) dosage of 22 mg·g^(-1),and air flow rate of 1.46 L·min^(-1).X-ray photoelectron spectroscopy analysis of the pyrite samples showed the formation of Fe(Ⅲ)and FeSO_(4) during the cyanidation process.The cyanide that adsorbed on the pyrite surface after cyanidation mainly existed in the forms of free cyanide(CN^(-))and ferrocyanide(Fe(CN)_(6)^(4-)),which were effectively removed by Na_(2)SO_(3)/air oxidation.During the decyanation process,air intake promoted pyrite oxidation and weakened cyanide adsorption on the pyrite surface.This study has practical significance for gold enterprises aiming to mitigate the environmental impact related to cyanide residues.

关 键 词：PYRITE CYANIDE DECYANATION sodium sulfite/air oxidation cyanide residue 

分 类 号：TF831[冶金工程—有色金属冶金]