Processes and systems for recovering promoter-containing compounds, for example, perrhenates, from promoter-containing catalyst substrates, for example, substrates containing precious metals, such as silver, are disclosed. The processes include contacting the substrates with a first solution adapted to remove at least some of the catalyst promoter from the substrates, for example, an oxidizing agent, to produce a second solution containing catalyst promoter, passing the second solution through a porous medium adapted to capture at least some of the catalyst promoter, for example, a ion exchange resin; and passing a third solution, for example, a base solution, through the porous medium to remove at least some of the catalyst promoter from the porous medium and produce a fourth solution containing compounds having a catalyst promoter. Systems adapted to practice these processes are also disclosed.