机械活化硫铁矿还原Fe^(3+)反应动力学

Kinetics of Fe^(3+) reduction by mechanical activated pyrite

硫铁矿烧渣是生产硫酸时产生的固体废弃物。在50%的硫酸溶液中加入硫铁矿烧渣,于115℃反应4h后过滤得到硫铁矿烧渣酸浸液。当酸浸液中Fe3+和Fe2+的浓度分别为2.016mol/L和0.138mol/L时,取酸浸液500mL,加入40g硫精矿,在90℃下反应240min,Fe3+被还原成Fe2+的转化率只有26.30%;加入40g机械活化硫精矿,在90℃下反应240min,Fe3+被还原成Fe2+的转化率达到76.75%。实验结果表明:通过机械活化,硫铁矿反应活性大大提高;机械活化硫铁矿与硫铁矿烧渣酸浸液中Fe3+反应符合收缩未反应芯模型,属化学控制;反应动力学方程为1-(1-x)1/3=kt,其活化能E0为35.12kJ/mol。

Pyrite cinder is a kind in solid waste in sulfuric acid industry. After adding pyrite cinders in sulfuric acid solution, acidic leaching solution of pyrite cinders was obtained by acting at 90 ℃ for 240 min and filtrating. The reduction ratios of Fe^(3+) to Fe^(2+) were 26.30% and 76.75% after 40 g pyrite or 40 g activated pyrite reacted with Fe^(3+) at 90 ℃ for 240 min in 500 mL solution, respectively. The concentration of Fe^(3+)and Fe^(2+) were 2.016 mol/L and 0.138 mol/L, respectively. Activity of pyrite is largely increased by mechanical activation. The reaction between activated pyrite and Fe^(3+) is controlled by chemical reaction and the reaction is applicable to the shrinking core model. The kinetics equation can be expressed as 1-(1-x)^(1/3)=kt and the active energy E_0 is 35.12 kJ/mol.