BS ISO 3087:2020 pdf download – Iron ores — Determination of the moisture content of a lot

BS ISO 3087:2020 pdf download – Iron ores — Determination of the moisture content of a lot 7.2.2 Normal reference method Apply the following procedure. a) Spread the test portion in a layer of nominal thickness not greater than 31,5 mm in the tared drying pan (5.1) and determine the total mass immediately. Record the total mass, the mass of the drying pan, the initial mass of the test portion (m 1 ) and the numerical value of 0,05 % of m 1 . To reduce drying time, it is recommended that the layer-thickness of the sample be kept as low as possible. It should be specified for particular ores by check experiments carried out beforehand. b) Place the drying pan with the test portion in the drying oven (5.2) set at 105 °C, and maintain this temperature for not less than 4 h. Remove the drying pan with the test portion from the drying oven and weigh it immediately while still hot in order to minimize any reabsorption of moisture. Otherwise, weigh the test portion after cooling in air in a container having a close-fitting airtight lid. In each case, report the method of weighing. c) Once more, place the drying pan with the test portion in the drying oven, heat for a further 1 h, and then repeat the weighing. d) Repeat the procedure described in item c) until the difference in mass between subsequent measurements becomes 0,05 % or less of the initial mass of the test portion. Record the total mass and the mass of the test portion after each additional hour of drying (m 2 and onwards). 7.2.3 Optional reference method for ores of high combined water content For ores containing 8 % or more combined water, the following procedure may be applied. a) Spread the test portion in a layer of nominal thickness not greater than 31,5 mm in the tared drying pan (5.1) and determine the total mass immediately. Record the total mass, the mass of the drying pan and the initial mass of the test portion (m 1 ). b) Place the drying pan with the test portion in the drying oven (5.2) set at 105 °C and maintain this temperature for not less than 24 h. Remove the drying pan with the test portion from the drying oven and weigh it immediately while still hot in order to minimize any reabsorption...