硫代硫酸盐浸金研究进展

硫代硫酸盐是一种能替代氰化物的最有应用前景的无毒浸金试剂。论述了硫代硫酸盐浸金的研发进展和浸金机理以及浸金过程中铜、氨等主要离子的作用,简单介绍了几种从浸出液中回收金的方法,讨论了该法应用于工业生产还需解决的几个问题。     

Improving the thermal stability of polysulfidic crosslinks by hexamethylene-1, 6-bis(thiosulfate) disodium salt as the curing agent of natural rubber

When vulcanized with sulfur, the natural rubber (NR) usually accompanies reversion, and the proportion of polysulfidic crosslinks decreases considerably, leading to significantly performance decay. In the rubber industry, hexamethylene-1, 6-bis(thiosulfate) disodium salt (HTS) is used as a multifunctional agent to improve not only the reversion and fatigue properties of NR, but also the adhesive properties between NR and steel cords. However, there is few research about the working mechanism of HTS. In this work, HTS is added to belt compounds in doses of 0 to 5 phr. The cure characteristics, crosslinking structures, physical-mechanical properties, dynamic viscoelastic behavior, and T-pull adhesion forces of the NR composites are investigated. The results show that the total crosslinking density and T-pull adhesion forces of the composites both pass through a maximum and then decrease with the increasing dosage of HTS. Meanwhile, the formation of hybrid crosslinks during the prolonged cure time enhances the thermal stability and retention of the polysulfidic crosslinks of the NR composites. Surprisingly, the reduction in the proportion of polysulfidic crosslinks from optimum cure time (Tc₉₀) to 60 min just reaches 15.9% with the addition of 5 phr HTS, whereas that value is 30.9% without adding HTS, which shows the excellent antireversion ability of the HTS in the belt compound. Our work reveals some new features of HTS, which can lead to a more profound understanding of HTS.     

硫代硫酸盐浸金技术研究现状

硫代硫酸盐因绿色无毒、浸金速率快、试剂价格便宜等优点被认为是最有前景的氰化替代试剂。系统综述了硫代硫酸盐浸金体系的工艺研究与发展现状，重点阐述了不同硫代硫酸盐浸金体系的工作原理，并针对传统硫代硫酸盐体系存在的问题与对策进行了讨论，分析了无氨-硫代硫酸盐浸金体系潜在的工业应用前景。新型硫代硫酸盐体系的开发与应用将为推动我国黄金行业技术进步和健康可持续发展提供理论借鉴和技术支撑。     

联产二氯乙酸和巯基乙酸的研究

以氯乙酸母液为原料 ,采用硫代硫酸钠法将其转化为二氯乙酸和巯基乙酸 ,在反应温度 70℃ ,母液中一氯乙酸与硫代硫酸钠物质的量比为 1∶1,反应时间 4.5h ,还原用锌粉量为 8g,最佳反应条件下 ,可得到质量分数为 98.6 %的二氯乙酸 ,收率达 93% ;同时获得收率为 88%的巯基乙酸