Centenary of flotation symposium, Brisbane, QLD, 6-9 June 2005. - pp. 1-8Compañía Minera Huasco (CMH) operates an iron pellet plant in central Chile. CHM desired to produce a low silica pellet for the export market wher the SiO2 grade should not exceed 1.5%. It is common practice in other countries to float quartz from hematite with relative ease. However, the silicates contained in the magnetite ore of CHM are only present as quartz in small quantities and the major undesirable silicates are difficult to float (feldspar, chlorite etc.).
CHM spent considerable time on developing a reverse flotation process and reagent suit to try and reduce silica content to acceptable levels. However, extensive laboratory and pilot plant tests with conventional mechanical tank type cells and with column cells failed to produce the required reduction in impurities. A series of tests with pneumatic flotation cells indicated that this type of flotation technology could achieve the required silica target. A 500 tph Imhoflot pneumatic flotation plant was subsequently constructed and successfully commisioned by CHM, making it one of the largest iron ore flotation plants in the world.
This paper details the background and testing that was undertaken by CHM which led them to choose pneumatic flotation as preferred process and compared the test results with that achieved in the industrial plant.
