ISO/TC 79/SC 12 - Aluminium ores

The heterogeneity of distribution is characterized by the distribution variance and is determined by experimentally measuring the sampling variance. Because both the composition variance and distribution variance contribute to the measured sampling variance, it is necessary to separate these two components. Two methods of data analysis are permitted: Visman's theory of sampling which uses classical statistics and the variogram method which gives a better estimate because of taking into account serial correlation between adjacent increments.

Specifies the experimental methods to be applied for checking the precision of sampling of aluminium ores, expressed in terms of the standard deviation, being carried out in accordance with the methods prescribed in ISO 8685.

Sets out requirements for the sampling from moving streams and stationary situations, including stopped-belt sampling, to provide gross samples for sample preparation. The procedures recommended may not be applicable in cases of extreme segregation, e.g. very wet ore due to its sticky nature, or very dry ore due to generation of dust.

Specifies a titrimetric method, free from mercury pollution, using potassium dichromate as titrant after reduction of the trivalent iron by tin(II) chloride and titanium(III) chloride. Applies to ores containing between 2 % and 50 % of iron oxide.

Specifies methods of treatment of gross samples and subsamples in order to preparate samples for the determination of moisture, chemical analysis and physical testing. Annex A forms an integral part of this standard. Annexes B, C, D, E and F are for information only.

Specifies an experimental method for determining the heterogeneity of constitution which is required for the determination of the minimum sample mass. Shows an example of typical calculation.

Specifies experimental checking methods, if the sampling is carried out in accordance with ISO 8685 or ISO 6140. Describes the analysis of experimental data as well as sampling and sample preparation methods. Includes numerical examples (tables 3 to 5).

Is applicable to ores containing between 0,005 % (m/m) and 0,1 % (m/m) of vanadium pentoxide. Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report. Annex A (normative) gives the flowheet of the procedure for the acceptance of test results, annex B (informative) shows the graphical representation of precision data.

Applies to the samples taken from bulk aluminium ores. Annex A specifies a method to be used when it is difficult to carry out sieving, crushing and dividing owing to the sample being adhesive or excessively wet. Annex B specifies methods of correction for sprayd water and/or rainfall.

The method is applicable to materials having phosphorus contents, expressed as diphosphorus pentoxide between 0,01 and 5 % (m/m). The arsenic content of the sample does not affect the determination. Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report. An annex shows the flowsheet of the procedure for the acceptance of test results.

The method is applicable to products having aluminium contents, expressed as aluminium oxide, in the range 30 to 65 % (m/m). Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report.

The method ist applicable to all aluminium ores having loss of mass values in the range of 10 to 30 %. Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report.

The method is applicable to products having hygroscopic moisture contents, expressed as water, between 0,1 and 5 % (m/m), and shall be used to correct the results obtained for aluminium and loss of mass at 1 075 °C to a dry basis. Specifies principle, material, apparatus, sampling and samples, procedure, expression of results and test report.

The samples are to be used for the determination of analytical values of constituents in aluminium ores on a dry basis. The method does not apply, when the analytical constituent to be calculated on a dry sample basis is aluminium or for determination of loss of mass at 1 075 °C. Specifies principle, apparatus, sampling and samples and procedure.

The method is applicable to ores containing between 0,5 and 8 % (m/m) of titanium dioxide. Specifies principle, reagents, apparatus, sampling and samples, procedure, expression of results and test report.

The method is applicable to ores containing between 1 and 25 % (m/m) silicon dioxide. Specifies principle, reagents, apparatus, sampling and preparation of samples, procedure, expression of results and test report.

The method ist applicable to ores containing between 2 and 50 % (m/m) iron oxide. The method has been chosen to avoid interference from platinum which may occur with the use of platinum crucibles. Specifies principle, reagents, apparatus, sampling and preparation of samples, procedure, expression of results and test report.