Abstract: A tunnel kiln was used to process stainless steel dust from the Stainless Steel Branch of Baosteel. The technical process is that coke, 35% of the dust mass in dosage, was placed outside around the dust, and different proportions of iron scales were reduced in the silicon carbide tank for 42 h at 1 200℃. It is shown that the sintering of the dust can be realized in the tunnel kiln process and the strength of the sinter is improved economically and effectively by adding the iron scale (20% of the dust mass in dosage). The iron grade increases by adding the iron scale, but the nickel and chromium grades decrease. A method of estimating the reduction rate was proposed since the metallization rates of nickel and chromium were difficult to be measured. This method was applied to this test, and it is found that under the condition of the tunnel kiln process, the metallization rates of iron and nickel are 92.55% and 97.83%, respectively, and the metallization rate of chromium can reach at least 35.5%.