Patent ID: 8188329
Filing Date: 2012-05-29
Classification: C22B,F23G,Y02P

Abstract:
1. A method for recycling potentially explosive precious metal-containing materials having organic fractions that combust with great energy, the method comprising the steps: (A) pyrolyzing or carbonizing the materials under reduced oxygen supply, and (B) oxidatively combusting the organic fractions, wherein steps (A) and (B) are carried out sequentially in an indirectly heated furnace chamber, such that a batch in the chamber is not changed and the furnace is not opened, wherein step (A) comprises establishing an oxygen-depleted atmosphere containing maximally 6 wt-% oxygen in the interior of the chamber by making it inert with protective furnace gas, and determining an end point of the pyrolysis or carbonization, wherein step (B) proceeds right after the pyrolysis or carbonization by supplying air or by supplying oxygen to the chamber, wherein the method is carried out in batch operation in first and second chambers, wherein step (A) is carried out on a first batch of material in the first chamber while a second batch of material is supplied to the second chamber, then step (B) is carried out for the first batch in the first chamber while step (A) for the second batch proceeds in the second chamber, and while a switch to step (B) is made in the second chamber, the first chamber is again supplied with material for step (A) and wherein the first and second chambers are operated in alternating operation with a single thermal after-combustion.