(1. 中南大学 化学化工学院，长沙 410083；
2. 中南大学 地学与环境工程学院，长沙 410083)
摘 要: 对乙氧羰基硫脲和丁黄药组合捕收剂方案浮选德兴铜矿进行了小型和工业试验研究。结果表明，与丁黄药单一捕收剂方案相比，组合捕收剂方案可使石灰用量降低2/3，实现铜铁混合精矿在pH值为10.5左右的高效浮选分离，显著提高矿山铜、金和钼的回收率。采用普遍化微扰理论和密度泛函B3PW91/6-31G(D)计算对上述实验结果进行了理论分析。ECTU的反应中心为硫代羰基中的硫原子，ECTU的最高占据分子轨道与次最高占据分子轨道的能量接近，主要由硫代羰基中的硫原子组成。ECTU的最低未占据分子轨道由官能团—O—C(=O)—N—C(=S)—N—中各原子的pz轨道组成，为一大π键，具有强烈接受和分散电子对的能力。ECTU易与表面电子组态为(t2g)6(eg)3Cu(Ⅱ)或t6e4 Cu(Ⅰ)的硫化铜矿物形成正配键和反馈键，而难与表面电子组态为(t2gа)3(egа)2 Fe(Ⅲ)或(t2g)6Fe(Ⅱ)的硫化铁矿物作用。UV和FTIR光谱结果进一步证实了ECTU对铜矿物具有优异的捕收能力，对硫矿物具有较好的选择性。
关键字: 乙氧羰基硫脲；铜硫；捕收剂；回收率；浮选；分离
（1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. School of Geoscience and Environmental Engineering, Central South University, Changsha 410083,China）
Abstract:The bench-scale and industrial flotation test results of Jiangxi Copper Corporation’s Dexing Copper Mine show that the flotation separation of Cu/Fe sulfide minerals is achieved at pH value about 13 for sodium butyl xanthate (SBX) and pH value around 10.5 for combined collectors ethoxylcarbonyl thiourea (ECTU) and SBX. Compared with the SBX system, the consumption amount of lime decreases 2/3 and the recoveries rates of Cu, Au and Mo in the copper concentrates increase by the combined collectors system. The flotation results were analyzed from the structure-activity of collectors by generalized perturbation theory and density functional calculation at B3PW91/6-31G(D) level. The S atom of C=S group in ECTU molecule is at the reactive centre of ECTU. The highest occupied molecular orbit (HOMO) of ECTU and next higher occupied molecular orbit (NHOMO) are mainly constitued by p-orbit of thiocarbonyl sulfur atom and their orbital eigenvalues have similar values. The lowest unoccupied molecular orbit (LUMO) of ECTU, which is constituted by pz-orbit of every atoms in the conjugate —O—C(=O)—N—C(=S)—N— group and pleased with accepting richly d-orbital electrons (feedback electrons) from the (t2g)6(eg)3Cu(Ⅱ) or t6e4 Cu(Ⅰ) configuration of copper cation on the surfaces of copper sulfide minerals, results in the formation of dative π-bond. The iron atom, which has a (t2g)6(eg)0Fe(Ⅱ) or (t2gа)3(egа)2 Fe(Ⅲ) configuration on the surfaces of iron sulfide minerals, has difficulty in offering its d-orbital electrons (feedback electrons) to LUMO of ECTU. ECTU collectors are powerful for copper sulfide minerals and very selective against iron sulfides, which is further confirmed by UV and FTIR spectra.
Key words: ethoxylcarbonyl thiourea; Cu/Fe sulfide minerals; collector; recovery rate; flotation; separation
