Iron Ore Down. Of Yunnan Longling Sulfur Sulfur Test Study

At the moment, as the development of China's economy, urban and rural conditions improved increasingly, our country's demands for steel is enlarged gradually and our country become the world's first steel superpower in production. However, due to the indiscriminate felling of iron ore in recent years, most of the high-quality iron ore has been depleted, the remaining most of them has a characteristic of "poor,mixed,fine".The average grade of iron ore only is about 30%, and the harmful impurities S,P,SiO2,Al2O3 has a high level, which resulting in our country's demand for high-quality iron ore of foreigner is increasing day after day, in order to fill the lack of production on domestic iron ore. Thus, the iron concentrator's top priority is improving the grade of iron concentrate, and reducing the harmful impurity elements.The sulfur in steel will produce hot shortness for steel, it will fracture when forging or rolling at a high temperature. So the sulfur content in steel is less than 0.05%, the sulfur content in iron has great impact to the quality of steel, so it requires the sulfur content in iron is not more than 0.2%.The iron ore from Yunnan Long ling contains the iron 35.36%, sulfur 1.17%, it has a high level in sulfur. The research on crude ore's properties shows that the crude iron ore are mainly magnetite, followed by hematite and limonite, iron sulfide and silicate iron ore, and sulfur minerals are mainly pyrite and magnetic pyrite. Through the analysis of crude ore's characteristics, we test in the comparison among several circuits like the single magnetic separation, magnetic after flotation, and flotation after magnetic. We choose the circuit:flotation after magnetic, and optimize based on it, then used the stage of grinding and stage of magnetic separation process.After a series of conditions test, it shows that the crude ore are grinded to-200 mesh 55%, after low intensity magnetic separation and chuck gangue we can get the iron ore crude concentrate with yield of 51.8%, iron grade 56.24%, sulfur grade 1.78%, iron recovery 82.39%. The iron ore crude concentrate are grinded to-200 mesh 90% and then through low intensity magnetic separation, we can get the iron ore concentrate with yield of 41.3%, iron grade 66.12%, sulfur grade 1.02%. iron recovery 77.23%.Through the magnetic test, we found that the iron ore concentrate by magnetic separation still has a high level in sulfur content, after identification, we can found the sulfur in iron ore concentrate exist with form of pyrrhotite, taking into account the strong magnetic of pyrrhotite, single weak magnetic separation can hardly achieve effective separation from the two, so we make the anti-flotation test to separate sulfur from iron ore concentrate.In the test of anti-flotation, contrapose the collector and activator for the process, we research many condition contrast, and determine to use CuSO4+H2SO4 as the flotation activator, use isoamyl xanthate as the collector, finally we get a good result which the iron ore concentrate with iron grade 66.72%, which content sulfur 0.1%, iron recovery 75.63%.After the verification of expanded test, industrial production gained a high-quality iron ore concentrate with iron grade more than 66%, sulfur grade less than 0.1%.