Jiyun Zheng,Guogang Shu,Wei Wang,Qiulin Li,Wei Liu
Surface quality improvement by Cu activation and oxidation roughening process was studied during electroless coating Cu on boron carbide (B 4 C) particles. The surface morphology was characterized by scanning electron microscope (SEM) and the phase identification was determined by X-ray diffraction (XRD) analysis. Two aspects concluding surface activation and surface roughening were investigated to understand the effect of each on Cu coating. Cu activation process increased surface activity of B 4 C by pre-deposition Cu nano-crystals, which was effective and cost-saving when compared with conventional Pd activation method. The influence of activation pH on electroless Cu coating was discussed and a moderate pH 12 is suitable for Cu deposition. Surface roughening process availably promoted wettability of B 4 C particles with aqueous solution. Etched pits were formed on B 4 C surface and resulted in fresh surface exposed after oxidization roughening process, which was beneficial for Cu bonding and coating on B 4 C surface.
Cuihuan Lv,Jinpeng Cai,Guohui Wang,Jiuxiu Chen,Hao Lai,Peilun Shen,Dianwen Liu
Organic depressants often exhibit low selectivity at high dosages, and introduce risks of concentrate dewatering. The combined depressants composed of inorganic and organic substances can significantly reduce reliance on organic depressant dosage, providing a promising solution to this challenge. In order to achieve highly efficient separation of sphalerite and pyrite in the CuSO 4 -butyl xanthate (PBX) flotation system, the combined depressant Fe 2+ / baicalin (BCL) was innovatively employed to inhibit copper-activated pyrite. The flotation tests indicate that compared with the single depressant BCL, the combined depressant Fe 2+ /BCL demonstrates superior selective inhibitory effects on copper-activated pyrite. For artificially mixed ores, a zinc concentrate is obtained with a zinc grade of 62.33 % and a zinc recovery of 93.86 % when the combined depressant of 10 mg/L Fe 2+ and 5 mg/L BCL are used, and the separation efficiency is significantly improved from 40.66 to 79.69 %. Adsorption characteristic studies indicated that BCL exhibits stronger affinity for copper-activated pyrite than for sphalerite. The introduced Fe 2+ provide additional active sites, thereby enhancing the depression effect on copper-activated pyrite. Following Fe 2+ /BCL modification, the adsorption of PBX on copper-activated pyrite was hindered, while having no substantial impact of that on sphalerite, which is also confirmed by molecular dynamics simulations. Therefore, the combined depressant Fe 2+ /BCL markedly widened the hydrophobicity difference between sphalerite and pyrite, creating the potential for their effective separation.
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