Experimental results describing the pressure drop and collection efficiency of a quartz micro-fiber filter are presented in this study. The filter utilized had a porosity of 0.698 and mean fiber diameter of 1.1!m. For the tests performed, the filter was a disk with an effective diameter of 3 cm. The permeability tests of the filters were measured by varying the superficial gas velocity from 0.013 to 1.49m/s and the temperature from 26.5 to 666oC. The collection efficiency tests were accomplished for temperatures ranging from ambient to 700oC at a filtration velocity of 0.05 m/s. The test powder utilized was a phosphate rock concentrate with a density 2973 kg/m3 and average diameter of 4.6!m. The permeability test results showed that, for the same gas velocity, the pressure drop increased with the gas temperature. This dependence was reflected in the measured values of the permeability constant, k1, which increased with temperature. The experimental points were well fitted by a linear correlation. The filtration tests also showed a clear dependence between filter efficiency and test temperature: smaller filter efficiencies were obtained as the gas temperature was increased.