Fireproof Concrete Masses for Lining in Foundry
S. Pavlenko and I. Rekhtin
Appears on pages(s):
concrete; fire resistance; high-alumina cement; lining
Today, in Russia, carbide - silicon and aluminate - silicate packing masses are generally used for lining blast - furnace chutes. They contain re-fractory clay, coal-tar pitch and resins as binders which emit carcinogenic sub-stance dangerous for a human organism. Thirty compositions of chute concrete masses excluding any carcinogenic substance were studied and tested on a chute by the Siberian State University of Industry in conjunction with the Kuznetsk Metallurgical Combine company. The best results were obtained with the following composition: 75 % fused electrocorundum, 20 % refractory clay, 5 % high-alumina cement and 7.3 % water (above 100 %). Thermal resistance in heat changes was above 25 cycles at 800 ‘C, apparent density was 2.54 to 2.75 g/cm3, compressive strength was 76.6 and 79.2 MPa at 110 ‘C and 1450 ‘C, respectively, slag resistance was 0.1 to 0.2 mm at 1450 ‘C, firing shrinkage was 0.2 % with no corrosion observed. The composition developed increased the service life by 10 times compared with the composition generally applied and does not emit any carcinogenic matters. However, in view of the economic crisis and high cost of the electrocorundum, its application is limited. Therefore, we have developed compositions with a high - alumina product (HAP), the waste from the Yurga abrasive works, as a replacement for the electrocorundum. They are as follows: (i) 35 % HAP, 20 % fireclay powder, 15% refractory clay, 30 % waste from the production of silicon carbide; (ii) 48 % HAP, 20 % fireclay powder, 15 % refractory clay, 32 % waste of silicon car-bide with a particle size distribution of 3 to 0 mm. These compositions exhibit < 50 % reduction in strengths (from 80 to 40 MPa) at 1450 ‘C with other indices (slag resistance, iron resistance, apparent density and shrinkage) being the same as for compositions containing pure fused electrocorundum. Their cost is simi-lar to that of the concrete masses generally used but the service life is 4 times longer which was proved by testing in a central chute of a blast furnace.