ISO/TC 27/SC 5/WG 7 - Brown coals and lignites

This document specifies volumetric methods for the determination of total humic acids and free humic acid of brown coals and lignites.

This document describes methods for the determination of true relative density and the apparent relative density of brown coals and lignites.

This document specifies a method of determining the volatile matter of brown coals and lignites.

This document specifies a semi-automatic method for determination of the yield of benzene-soluble extract in brown coals and lignites.

This document specifies a method of determining the volatile matter of brown coals and lignites by the one furnace method.

ISO 647:2017 specifies a method for the determination of the yields of tar, water, gas and coke residue obtained from brown coal and lignite by distillation to a final temperature of 520 °C.

ISO 1952:2008 describes the extraction from solid mineral fuels by dilute hydrochloric acid and determination of extractable sodium, potassium, calcium, iron and magnesium.

ISO 5068-2:2007 specifies a method for the determination of the moisture content in the analysis sample of brown coals and lignites using an indirect gravimetric method.

ISO 5068-1:2007 specifies two methods for determination of the total moisture content of brown coals and lignites using an indirect gravimetric single-stage method and a two-stage method.

ISO 1017:2006 specifies a method of determining the mass fraction of acetone-soluble material ("resinous substance") in the benzene-soluble extract from brown coals and lignites.

Brown coals are classified in this International Standard according to the following properties: total moisture content calculated on the ash-free basis; tar hiels calculated on the dry, ash-free basis. In tables class numbers, group number and code numbers of brown coal types are given.

ISO 975:2013 specifies a semi-automatic method for determination of the yield of benzene-soluble extract in brown coals and lignites.

ISO 5071-1:2013 specifies a method of determining the volatile matter of brown coals and lignites.

ISO 5073:2013 specifies volumetric methods for the determination of total humic acids and free humic acid of brown coals and lignites.

ISO 5072:2013 describes methods for the determination of true relative density and the apparent relative density of brown coals and lignites.

Describes the principle, the reagents, the preparation of the sample, the apparatus and calibration, the procedure and precision of the method, the expression of results and the contents of the test report.

A sample of toluene-soluble extract from brown coal or lignite obtained by the procedure describes in ISO 975 is extracted with acetone at a temperature of 18 to 22 °C. The soluble fraction is filtered or centrifuged off and after evaporation of the solvent dried to constant mass. The percentage of acetone-soluble material is calculated from the mass of reidue after drying.

Specifies two basic procedures: a) A single-stage method which can be used for determination of the total moisture content of the special moisture sample or of a moisture sample taken from a common sample. b) A two-stage method which can be used for determination of the residual moisture content and, if required, also the total moisture content of a special moisture sample or of a moisture sample taken from a common sample. The single-stage method consists in drying the sample to constant mass at a temperature of 105 to 110 °C under specified conditions. The two stage method contains additionally drying at temperaures not exceeding 40 °C.

The sample is heated in an aluminium retort to a temperatur of 520 °C. The products of decomposition pass into a water-cooled receiver; the tar and water are condensed while gaseous products pass to atmosphere. The coke residue and the receiver and its contents are weighed. The mass of tar is obtained by difference to the mass of water determined by entrainment with toluene or xylene. A separate determination of moisture in the coal, also by entrainment with tulene or xylen, is amde so that the decomposition water can be calculated. The peecentage of gas is obtained by subtracting from 100 the sum of the percentages of coke residue, of tar and decomposition water.