Abstract: A reactor/transporter apparatus for coating particles by thermally decomposing at least one metal carbonyl into selected metal values and carbon monoxide with the metal values depositing on the particles. The reactor/transporter includes an upper end, a lower end and a source of transport fluid including the metal carbonyl. The transport fluid is supplied into the reactor/transporter for coating particles as they travel from the lower to the upper end. A separator is connected to the upper end of the reactor/transporter for separating the particles from the transport fluid. A downcomer is connected to the separator for collecting the particles. A heater heats the particles and a valve regulates the flow of particles into the reactor/transporter from the downcomer. In addition, the reactor/transporter has a purge vessel for removing coated particles.