1、International Standard ( 8557 0 0 4 4igb INTERNATIONAL ORGANIZATION FOR STANDARDlZATlON*MEXQYHAPOAHAR OPrAHH3AUMR flOCTAHAAPTl43AUilHRGANlSATlON INTERNATIONALE DENORMALISATION Aluminium ores - Determination of hygroscopic moisture in analytical samples - Gravimetric method Minerais alumineux - D 8 s
2、 Price based on 2 pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword IS0 (the International Organization for Standardization) is a worldwide federation of nat
3、ional standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Interna
4、tional organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. They a
5、re approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 8557 was prepared by Technical Committee ISO/TC 129, Aluminium ores. Users should note that all International Standards undergo revision from time to time and that a
6、ny reference made herein to any other International Standard implies its latest edition, unless otherwise stated, 0 International Organization for Standardization, 1985 0 Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISONot for Res
7、aleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD IS0 8557-1985 (E) Aluminium ores - Determination of hygroscopic moisture in analytical samples - Gravimetric method 1 Scope and field of application This International Standard specifies a gravimetric loss
8、 of mass method for the determination of hygroscopic moisture in analytical samples of aluminium ores. The method is applicable to products having hygroscopic moisture contents, expressed as water (H20), in the range 0,l to 5 % (m/m), and shall be used to correct the results obtained for aluminium a
9、nd loss of mass at 1 075 Y to a dry basis. NOTE - The hygroscopic moisture can be taken into account for other determinations by using a pre-dried sample prepared in accordance with IS0 8558. 2 Reference IS0 8558, Alumhium ores - Preparation of pre-dried test samples. 3 Principle Drying of the test
10、portion in air at approximately 105 OC and recording of the loss of mass. 4 Material 4.1 Desiccant: activated alumina, magnesium perchlorate or diphosphorus pentoxide. NOTE - Activated alumina should be freshly activated by heating overnight at 300 + 10%. 5 Apparatus Ordinary laboratory apparatus an
11、d 5.1 Weighing bottles, of glass or metal, of diameter approx- imately 50 mm. 5.2 Dishes, fiat bottom, for equilibration of samples with the laboratory atmosphere. The bottom of the dishes shall be about 20 cm2 in area. 5.3 Laboratory oven, capable of being controlled at 105 * 2 T. 5.4 Desiccator. 6
12、 Sampling and samples 6.1 Sample Use an air-dried sample with a particle size of less than 150 pm. 6.2 Preparation of the test sample Take approximately 10 g of the laboratory sample and transfer to a dish (5.21. Spread the sample evenly and allow to equilibrate with the laboratory atmosphere for a
13、minimum of 2 h. 7 Procedure 7.1 Number of determinations Carry out the determination in duplicate on each aluminium ore, 7.2 Preparation of the weighing bottle Dry a weighing bottle and lid (5.1) by heating for 1 h in the laboratory oven (5.31, controlled at 105 f 2 “C. Transfer bottle and lid to th
14、e desiccator (5.41, containing a suitable fresh desic- cant (4.1), and allow to cool. Weigh to the nearest 0,000 1 g after slightly lifting the lid and quickly replacing it. Record the mass (ml). NOTE - A heat sink introduced into the desiccator and comprising a substantial mass of metal may be used
15、 to significantly reduce the cool- ing time. 1 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 8557-1985 (El 7.3 Test portions 8 Expression of results The hygroscopic
16、 moisture content H, expressed as a percen- tage by mass as water (H20), is given by the formula m2 - m3 m2 - ml x 100 where ml is the mass, in grams, of the weighing bottle; m2 is the mass, in grams, of the weighing bottle with ore before drying; m3 is the mass, in grams, of the weighing bottle wit
17、h ore after drying. Take as the final result the mean of the duplicate deter- minations. Weigh, to the nearest 0,000 1 g, approximately 2 g of pre- equilibrated test sample (6.2) directly into the dried and tared weighing bottle (7.2). Record the mass (m2). Also at this stage weigh test portions req
18、uired for the determination of con- stituents for which correction of the analytical values to a dry basis is required (e.g. loss of mass at 1 075 OC and aluminium content) and transfer such test portions to the vessels specified. 7.4 Determination Transfer the uncovered bottle with its lid to the l
19、aboratory oven and dry at 105 f 2 OC for 1 h. Close the bottle, allow to cool in the desiccator for 30 to 45 min and re-weigh after slightly lifting the lid and quickly replacing it, NOTE - Where a heat sink has been used in the desiccator, a 10 min cooling time will be sufficient. Repeat the drying
20、 at 105 OC for 30 min, cooling in a desiccator for 30 to 45 min, and weighing steps for as many times as necessary to achieve constant mass in the test portion, i.e. until the difference between two successive weighings does not ex- ceed 0,02 %. Record the constant mass (m3). 9 Test report The test
21、report shall include the following information : a) details necessary for the identification of the sample; b) reference to this International Standard; c) results of the analysis; d) reference number of the results; e) any characteristics noticed during the determination and any operations not spec
22、ified in this International Stan- dard or in the International Standard to which reference is made which may have had an influence on the results. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
