The concentrations of S2O3 2- and SO3 2- were measured in gold leaching systems,including thiosulfate system,polysulfide system and the modified lime sulfur synthetic solution(ML)system in the process of chemical reac...The concentrations of S2O3 2- and SO3 2- were measured in gold leaching systems,including thiosulfate system,polysulfide system and the modified lime sulfur synthetic solution(ML)system in the process of chemical reaction.The interactions among S2O3 2- ,SO3 2-and S 2-were discussed.The behavior mechanism of sulfur-bearing reagents was proposed to describe the process reactions and their Gibbs free energy.The proper quantity oxygen and SO3 2- reduce decomposition of S2O3 2-and react with sulfur derived from the decomposition of SX 2- .So,SO3 2-ions have action to stabilize sulfur-bearing system and are favorable to leach gold.展开更多
Sulfides in the high-sulfur bauxite lead to serious steel equipment corrosion and alumina product degradation via theBayer process,owing to the reactions of sulfur and iron-containing phases in the sodium aluminate so...Sulfides in the high-sulfur bauxite lead to serious steel equipment corrosion and alumina product degradation via theBayer process,owing to the reactions of sulfur and iron-containing phases in the sodium aluminate solution.The effects ofiron-containing phases on the transformation of sulfur-bearing ions(S2?,223S O?,23SO?and24SO?)in sodium aluminate solutionwere investigated.Fe,Fe2O3and Fe3O4barely react with23SO?and24SO?,but all of them,particularly Fe,can promote theconversion of223S O?to23SO?and S2?in sodium aluminate solution.Fe can convert to3Fe(OH)?in solution at elevatedtemperatures,and further react with S2?to form FeS2,but Fe2O3and Fe3O4have little influence on the reaction behavior of S2?insodium aluminate solution.Increasing temperature,duration,dosage of Fe,mole ratio of Na2Ok to Al2O3and caustic sodaconcentration are beneficial to the transformation of223S O?to23SO?and S2?.The results may contribute to the development oftechnologies for alleviating the equipment corrosion and reducing caustic consumption during the high-sulfur bauxite treatment bythe Bayer process.展开更多
The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation w...The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.展开更多
基金Project(2007ZDGC-11) supported by "13115" Science and Technique Innovation Program of Shaanxi Province, ChinaProject(09JK561) supported by Educational Commission of Shaanxi Province of China
文摘The concentrations of S2O3 2- and SO3 2- were measured in gold leaching systems,including thiosulfate system,polysulfide system and the modified lime sulfur synthetic solution(ML)system in the process of chemical reaction.The interactions among S2O3 2- ,SO3 2-and S 2-were discussed.The behavior mechanism of sulfur-bearing reagents was proposed to describe the process reactions and their Gibbs free energy.The proper quantity oxygen and SO3 2- reduce decomposition of S2O3 2-and react with sulfur derived from the decomposition of SX 2- .So,SO3 2-ions have action to stabilize sulfur-bearing system and are favorable to leach gold.
基金Project(51604309)supported by the National Natural Science Foundation of ChinaProject(201509048)supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare IndustryProject(2015CX001)supported by the Innovation-driven Plan in Central South University,China
文摘Sulfides in the high-sulfur bauxite lead to serious steel equipment corrosion and alumina product degradation via theBayer process,owing to the reactions of sulfur and iron-containing phases in the sodium aluminate solution.The effects ofiron-containing phases on the transformation of sulfur-bearing ions(S2?,223S O?,23SO?and24SO?)in sodium aluminate solutionwere investigated.Fe,Fe2O3and Fe3O4barely react with23SO?and24SO?,but all of them,particularly Fe,can promote theconversion of223S O?to23SO?and S2?in sodium aluminate solution.Fe can convert to3Fe(OH)?in solution at elevatedtemperatures,and further react with S2?to form FeS2,but Fe2O3and Fe3O4have little influence on the reaction behavior of S2?insodium aluminate solution.Increasing temperature,duration,dosage of Fe,mole ratio of Na2Ok to Al2O3and caustic sodaconcentration are beneficial to the transformation of223S O?to23SO?and S2?.The results may contribute to the development oftechnologies for alleviating the equipment corrosion and reducing caustic consumption during the high-sulfur bauxite treatment bythe Bayer process.
基金the Northeast Petroleum University Youth Science Foundation (No. 2019QNL-35)Guiding Science and Technology Plan Project of Daqing (No. zd-2021-39)。
文摘The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.
基金This work was supported by the National Natural Science Foundation of China(No.22273104,No.22022306,No.22288201)the Innovation Program for Quantum Science and Technology(No.2021ZD 0303305)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450202)Liaoning Revitalization Talents Program(No.XLYC 2203062)the Dalian Innovation Support Program(No.2021RD05).
