Process for preparing a spent catalyst for precious metals recovery

摘要

A process is provided for preparing a spent noble metal fixed-bed catalyst for precious metals recovery, comprising: a) adding the catalyst to a caustic solution to wash the spent catalyst and to make a wash slurry having an alkaline pH, wherein the spent catalyst has been in contact with chloroaluminate ionic liquid catalyst, and wherein the spent catalyst comprises from 5 to 35 wt % chloride; and b) filtering the wash slurry and collecting: i) a filter cake having from at least 70 wt % of the chloride in the spent catalyst removed and having the noble metals retained, and ii) a wash filtrate. Also provided is a filter cake comprising a washed consolidated cake having 40 to 75 wt % solids, a cake moisture content from 25 to less than 60 wt %, 0.1 to 1.5 wt % total noble metals, and a residual chloride content of from zero to less than 4 wt %.

主权项

1. A process comprising:
a. adding a spent noble metal fixed-bed catalyst comprising one or more noble metals to a caustic solution to wash the spent noble metal fixed-bed catalyst and to make a wash slurry having a pH from 7 to 12.5, wherein the spent catalyst has been in contact with a chloroaluminate ionic liquid catalyst, and wherein the spent catalyst comprises from 5 to 35 wt % chloride; and b. filtering the wash slurry and collecting: i) a filter cake having from at least 70 wt % to 100 wt % of the chloride in the spent catalyst removed and having from 90 wt % to 100 wt % of the one or more noble metals retained, and ii) a wash filtrate.