A Study On The Corrosive Wear Characteristics Of Stainless Steels Used In The Slurry Of Zinc Hydrometallurgy

Corrosive wear is one of the three main failure modes of materials. It is often found in the equipment used in the metallurgical machine, petrochemistry industry, energy sources and transportation, and hydropower etc. The removal of materials caused by corrosive wear is great and results in a great deal of loss for national economy. Therefore, it is of theoretical and practical significance to analyze the failure mode of materials and to develop the better corrosive wear resistance materials.The slurry of zinc hydrometallurgy is composed of H₂SO₄,ZnSO₄ and some solid particles. The failure mode of impeller (0Cr₂₅Ni₁₈Mo) of the pump used in zinc hydrometallurgy is corrosive wear. The corrosion action of slurry accelerates the abrasion of solid particles attacking the impeller, on the other hand, the action of abrasion damages the passive film on the surface of the material, and the new surface is emerged in the corrosive slurry, which accelerates its corrosion. Under the interaction of corrosion and wear, low hardness of impeller material results in the serious removal of material under the condition of zinc hydrometallurgy.The corrosive wear characteristic of three kinds of typical microstructure stainless steels was studied in the paper. The results show that the ferrite-austenite duplex stainless steel with good deformation strengthening ability has better corrosive wear resistance in the condition of high acidity, high solid/liquid ratio and velocity, the precipitation hardening stainless steel with high hardness has better corrosive wear resistance in the condition of low acidity, high solid/liquid ratio and velocity. On the other hand, when the environment is high concentration of sulfuric acid,high erosive speed and low solid/liquid ratio, the second phase strengthened austenite stainless steel has better corrosion wear resistance. In the condition of solid-liquid slurry with sulfuric acid, the surface of stainless steel is eroded by sulfuric acid and brittleness corrosive product is formed, and the abrasion of solid particles accelerates the peeling of corrosive production, therefore, the total loser increases.A kind ofσphase strengthened austenite stainless steel was developed in the paper. By means of adding alloy elements and heat treatment, the amount ofσphase in matrix can be increased. The increase ofσphase is benefit to improve the corrosive wear resistance of the stainless steel. Comparing the corrosive wear characteristic ofσphase strengthened austenite stainless steel, CD-4MCu and impeller (0Cr₂₅Ni₁₈Mo) in sulpuric acid slurry; it is found thatσphase strengthened phase austenite stainless steel has better corrosive wear resistance than the others.