土壤中镍钴铜硫有效态的提取测定和形态研究

Determination of Available Nickel, Cobalt, Copper and Sulfur in Soils

土壤中有效态镍、钻、铜用偏酸性溶液和络合剂溶液浸取;有效态硫用弱碱性溶液浸取,电动振荡1.5h。浸取液用原子吸收法测定镍、钻、铜,比浊光度法测定硫。由热力学自由能计算和化学物相分析证明,土壤中有效态Ni、Co、Cu和S均系硫化物转变成硫酸盐后被浸出。

It is experimentally established that the available nickel can be leached out in 90 minutes by a solution containing 1mol/L of HAc and NH_4Ac(pH7.10±0.05)with an 1:10 ratio of sample to leaching liquor; the available cobalt and copper by use of a solution containing 0.1mol/L HCl and 0.05mol/L EDTA, and available sulfur by use of 0.5mol/L NaHCO_3. The leached copper, cobalt and nickel are then determined by atomic absorption spectrometry and the leached sulfur by turbidimetry. With thermodynamic evaluation of free energies it was shown that the available nickel,cobalt,copper and sulfur in soils can only by leached out as their sulfate into which their sulfides have been converted.