Method of reprocessing metal dusts or chips and/or metal oxide dusts or chips, in particular grinding dusts

摘要

For reprocessing metal dusts or chips and/or metal oxide dusts or chips such as, for example, grinding dusts, calcium carbonate in a quantity from 10 to 20% by weight is admixed to the dusts or chips to be reprocessed. This admixing can be carried out after a low-temperature carbonisation of the feed material at 200 to 400 DEG C in order to separate off oils and greases, whereupon the resulting mixture is heated to a temperature from 950 to 1100 DEG C and held for 30 minutes to 3 hours at the end temperature. The heating up to the end temperature is here carried out in an advantageous manner at a rate of 10 to 25 DEG C/minute. After the holding time, the heated mixture can be quenched with cold water, whereupon leaching with water takes place, to which sodium carbonate can be added in quantities from 5 to 15% by weight. The leaching can be carried out at elevated temperature and under superatmospheric pressure, whereupon the residue remaining after the leaching can be mixed again with calcium carbonate, roasted once more and then leached.