基于Freundlich吸附等温方程测定氰化提金工艺用活性炭的吸附金容量

Determination of gold adsorption capacity of activated carbon in cyanide leaching process based on Freundlich adsorption isotherm equation

活性炭作为金的良好吸附剂广泛地应用在氰化提金生产工艺中,因此对活性炭吸附金性能的评价是非常重要的。在参考氰化提金生产工艺的基础上,模拟活性炭吸附氰化液中金的工艺过程,基于Freundlich吸附等温方程,建立活性炭吸附金容量的测定方法。通过考察一系列对吸附金容量测定的影响因素,优化和确定了测定方法的条件:吸附振荡时间为16 h,吸附溶液体积为150 mL,活性炭粒度在0.074 mm以下,振荡器转速为200 r/min,吸附溶液pH值为11.5,振荡温度为(30±1)℃,吸附溶液中氰化钠质量浓度为0.2 g/L。按照实验方法测定了2个活性炭实际样品的吸附金容量,结果的相对标准偏差(RSD,n=11)分别为4.2%和4.8%。并对不同活性炭的吸附金容量情况与碘值进行对比,结果表明实验方法具有可比性。

Activated carbon is a good adsorbent for gold and it has been widely used in cyanide leaching process.Therefore,it is very important to evaluate the gold adsorption performance of activated carbon.The cyanide leaching process was referred to simulate the adsorption of gold in cyanide solution by activated carbon.The determination method of gold adsorption capacity of activated carbon was established based on the Freundlich adsorption isotherm equation.A series of factors influencing on the determination of gold adsorption capacity were investigated to optimize and obtain the measurement conditions:the adsorption oscillation time was 16 h;the volume of adsorption solution was 150 mL;the grain size of activated carbon was less than 0.074 mm;the rotating speed of oscillator was 200 r/min;the pH of adsorption solution was 11.5;the oscillation temperature was(30±1)℃;the mass concentration of sodium cyanide in adsorption solution was 0.2 g/L.The gold adsorption capacities of two actual activated carbon samples were determined according to the experimental method.The relative standard deviation(RSD,n=11)was 4.2%and 4.8%,respectively.The gold adsorption capacities of different activated carbons were compared with their iodine numbers,and the results indicated that the proposed method was comparable.