Preparation of Ruthenium trichloride directly from ruthenium-containing waste material Ruthenium trichloride is one of the most important compounds of ruthenium and is an important chemical raw material in the fields of heterogeneous catalysis, homogeneous catalysis, electroplating, coating and so on. A method of preparing ruthenium trichloride directly from ruthenium waste material was introduced. The process is simple, the cost is low, the operation is simple, and the direct yield of ruthenium is more than 90%.
Ruthenium waste generally comes from aqua regia after extraction of gold, silver, platinum, palladium. The content of ruthenium is 50% ~ 90%, and contains a small amount of other precious metals, but the content of lead and silver is relatively high, generally greater than 1%, and the lead content can reach more than 30% in individual cases. Part of the ruthenium waste containing ruthenium in the range of 10%~30%, has been distilled once steam residue. The ruthenium waste used in this experiment contained ruthenium 67.86%. The results of qualitative spectral analysis of other precious metal elements and lead are listed in the table.
Distillation of ruthenium: 2 L distilled water was added into a 10L three-port distillation flask, and the feed port of the distillation flask was added. A large glass funnel is installed on the top, from which the material is slowly transferred into the distilling bottle, with each feeding of about 300g. If the material is blocked, inject a small amount of distilled water with the wash bottle around the funnel, the material can be smoothly into the distillation bottle. According to the ratio of NaOH: material = 5:1, 30% Na0H solution was added into the glass funnel of the feeding port for three times. After the first addition of Na0H solution, chlorine gas began to pass, and the electric furnace was used for intermittent heating. At this time, a large amount of ruthenium tetroxide vapor was generated, and the highest temperature reached 90C. In the distillation process, if the reaction rate slows down, the remaining two times of NaOH solution should be added. The whole process lasts for about 2 ho until the residual steam is light yellow and the end point of distillation is when the brown RuO4 gas is no longer produced.