摘要
以沉金后液为原料,采用SO_2为还原剂,研究在卤素以及卤素复合催化剂存在条件下还原沉金后液中的硒碲以及捕集贵金属金铂钯的工艺。结果表明:在85℃、硫酸浓度167 g/L、SO_2流量0.2 L/min的条件下,当Cl-催化剂浓度为1.1 mol/L、反应时间2 h,或当Br^-催化剂浓度为0.5 mol/L、反应时间3 h,或当I^-催化剂浓度为0.3 mol/L、反应时间2 h时,硒金铂钯还原率达到100%,碲还原率达到99.60%以上。采用卤素复合催化剂,当Na Cl与Na Br摩尔比为1:2时,有助于加快硒碲的还原,而且降低了催化剂的用量。SO_2催化还原后产物中含碲74.56%、铜11.85%、硒7.38%,贵金属金3.89%、铂0.19%、钯1.02%(质量分数);还原产物中碲以单质状态存在,产物形貌为球状体。热力学分析表明:硫酸浓度为167 g/L时,Se(Ⅳ)主要以H_2Se O_3形式存在,Te(Ⅳ)主要以H_3Te O_3^+形式存在;当溶液中有Cl^-存在时,溶液中H_3Te O_3^+在Cl^-缔合作用下逐渐转变为Te Cl_6^(2-),其电极电势较H_3Te O_3^+的正,促进碲的还原。
Selenium and tellurium were recovered and gold, platinum and palladium were captured from precipitated gold solution. SO_2 was used as reducer, halogen ion and composited halogen ions were used as catalysts in the reaction. The experimental results show that the reduction rates of selenium, gold, platinum and palladium are 100% and the reduction rate of tellurium is more than 99.60% when Cl^- concentration is 1.1 mol/L and reaction time is 2 h, or Br^- concentration is 0.5 mol/L and reaction time is 3 h, or I^- concentration is 0.3 mol/L, reaction time is 2 h. Under the condition of reaction temperature 85 ℃, H_2SO_4 concentration 167 g/L and SO_2 flow rate 0.2 L/min. The reaction speed is faster than that of Na Cl catalyst when the molar ratio of Na Cl to Na Br in the composited catalysts is 1:2. The mass fractions of tellurium, copper, selenium, gold, platinum, palladium in the reduction product are 74.56%, 11.85%, 7.38%, 3.89%, 0.19%, 1.02%(mass fraction), respectively. Tellurium exists in the form of simple substance in the reduction product and the morphologies of the product are spheroid bodies. Thermodynamic analysis show that Se(Ⅳ) mainly exists in the form of H_2 Se O_3, Te(Ⅳ) mainly exists in the form of H_3 Te O^(3+), H_3 Te O^(3+) gradually transforms into Te Cl_6^(2-) in association with Cl^-. Cl^- promots the reduction of Te(Ⅳ) because the electrode potential of Te Cl_6^(2-) is higher than H_3 Te O^(3+).
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2016年第4期901-907,共7页
The Chinese Journal of Nonferrous Metals
基金
新疆自治区科技支撑项目(201407300993)~~
关键词
SO2
还原
卤素离子
沉金后液
热力学
SO2
reduce
halogen ion
precipitated gold solution
thermodynamics
