Iron recovery from the waste generated during the cutting of granite

摘要

Metallic iron is present in the waste left whengranite blocks are cut. Thus, the purpose of this study wasto characterize this waste using chemical and particle sizeanalyses. To achieve this, X-ray diffraction and scanningelectron microscopy coupled with electron back-scattereddiffraction were used. To find the method with the bestmetallic iron recovery from the waste of ornamental rock,three distinct methods were examined: magnetic separation,table concentration and cyclone processing. The firstmethod involved three steps: (1) use of a wet high-intensitymagnetic separator, where only the equipment’s remainingmagnetic field was present; (2) the material from the firststep was then submitted to separation again, this time usinga magnet for rare earth particles; and (3) this material aftertwo separation processes was finally submitted to ferromagneticseparation. The second method used a concentrationtable set at various inclinations, oscillationfrequencies and wash flow rates. Meanwhile, for the thirdmethod, the cyclone tests, only the water pressure wasvaried. After each test, a chemical analysis was performedto determine the metallic iron present in each sample. Thetests revealed that magnetic separation presents the bestresults. Using this technique, a ferrous concentrate with93 % metallic iron content and a granite concentrate withonly 0.6 % metallic iron were obtained. On the other hand,in the table concentrator tests, the ferrous concentrate only