Study On The Ferronickel Submerged Arc Furnace Slag As Supplementary Cementitious Material And Its Properties

Nickel is an essential alloy element of stainless steel, when it is added to the production of stainless steel in the form of ferronickel alloy, it can not only effectively improve the utilization of nickel ore, but also significantly reduce the energy consumption and thus boost the production efficiency. With the rapid development of stainless steel industry, the demand for ferronickel alloy is increased and the scale of production is gradually promoted, thus more and more factories of ferronickel alloy produced by the submerged arc furnace using the laterite nickel ore are emerged . It causes large amount of ferronickel submerged arc furnace slags which is becoming serious ecological environment problem.In this study, two kinds of ferronickel submerged arc furnace slag supplementary cementitious materials with different activity are prepared by means of grinding and heat treatment prior to grinding. The effects of these supplementary cementitious materials on the workability, mechanical properties and some durability of the cement based composite cementitious system are studied. Using ferronickel submerged arc furnace slags as supplementary cementitious materials can not only reduce the pollution to the environment and the waste of land resources, but also reduce the cement used in the concrete, so it effectively reduces the production of cement which indirectly reduces not only the consumption of energy and resources, but the emissions of CO2. It suggests a good prospect of popularization and application for the ferronickel submerged arc furnace slag.The conclusions are as follows:①The ferronickel submerged arc furnace slag supplementary cementitious material has the effect of plasticizing and water reducing, with the increase of replacing dosage, the water demand of standard consistency of the composite cementitious system is lowered, thus the fluidity of mortar is raised and the workability is improved;②When the ferronickel submerged arc furnace slag is used as supplementary cementitious material, with the increase of replacing dosage, the compressive strength of hardened cement paste and mortar are both decreased at different ages, the flexural strength of 28 days is increased followed by a decrease after the dosage is above 10%, so the ratio of flexural strength to compressive strength is increased, thus the ductility of mortar can be a little bit improved.The numerical analysis results of pozzolanic effect show that both the two kind of ferronickel submerged arc furnace slag supplementary cementitious materials can improve the specific strength and strength contribution rate of pozzolanic effect;③Ferronickel submerged arc furnace slag supplementary cementitious material can improve the workability of concrete. By means of extra adding ground blast furnace slag, taking the full advantages of later strength enhancement of ground blast furnace slag and the plasticizing and water reducing effects of ferronickel submerged arc furnace slag supplementary cementitious material, when the two kinds of materials are both controlled at 5% in mass, the mechanical properties and the workability of concrete are both improved;The ferronickel submerged arc furnace slag supplementary cementitious material can improve 28 days carbonization resistance of concrete when the dosage is 10% in mass. It can also reduce the drying shrinkages of the hardened cement paste;④The heat treatment of ferronickel submerged arc furnace slag has little effect on the plasticizing and water reducing of the non-heattreated one.After four different temperature of heat treatment, all the gained ferronickel submerged arc furnace slag supplementary cementitious materials improve both the flexural strength and compressive strength of mortar. When the replacing dosage is 10%, the 800℃heat treatment benefits the strength best.The heat treatment of ferronickel submerged arc furnace slag has little effect on reducing drying shrinkage of hardened cement paste.All the above experiment results show that the ferronickel submerged arc furnace slag supplementary cementitious material has benefits of plasticizing, water reducing, enhancement of strength, reducing the drying shrinkage, enhancement of the carbonization resistance and so on, therefore, it is worthy of making use in practice.