Abstract: A shaft furnace comprises a body (2) made up of superimposed heated sections (3,4,5,6 and 7) each of which is provided with a tubular member (10,11,12,13 and 14) having its walls arranged at an angle of 3 to 4 deg. to the longitudinal axis of the furnace. The tubular members (10,11,12,13 and 14) are partially inserted one into another with a gap (15) formed therebetween; the opening area of the lower portion (16) of each tubular member (10-14) of each section (3-7) is 20 to 25 percent smaller than that of the upper portion (17) of the adjacent underlying tubular member (11) of the furnace section (4).In the area of the gaps (15), the upper portions of the tubular members are formed with pockets (30) which are connected with outlet pipes (20) intended for discharging gaseous and vaporous fumes from the furnace shaft.

Abstract: A method comprises heating the material to be treated without access of air at a temperature of 700.degree. to 800.degree. C. for a period of 1-2 hours, and then subjecting this material to subsequent magnetic separation.It is advisable that the furnace walls surrounding the material under treatment be heated to a temperature which is 100.degree. C. to 200.degree. C. higher than the boiling temperature of the volatile components of the material. Upon completion of the heating operation, the material being treated is cooled at a rate of 2 to 4 deg. per minute, whereafter iron sulphides are removed therefrom by means of magnetic separation, the intensity of magnetic field ranging from 1000 to 2000 oersted, and then copper sulphides are separated, with the field intensity ranging from 4500 to 6000 oersted.