ISO 20904-2020 pdf free.Hard coal -Sampling of slurries.
This document sets out the basic methods for sampling fine coal, coal rejects or tailings of nominal topsize <4 mm that is mixed with water to form a slurry.At very high ratios of fine solids to water when thematerial assumes a soft plastic form, the mixture is correctly termed a paste.Sampling of pastes is notcovered in this document.The procedures described in this document primarily apply to sampling of coal that is transportedin moving streams as a slurry. These streams can fall freely or be confined in pipes, launders,chutes,spirals or similar channels. Sampling of slurries in stationary situations, such as a settled or even a well-stirred slurry in a tank, holding vessel or dam, is not recommended and is not covered in this Document.This document describes procedures that are designed to provide samples representative of the slurrysolids and particle size distribution of the slurry under examination.After draining the slurry sample offluid and measuring the fluid volume, damp samples of the contained solids in the slurry are availablefor drying (if required) and measurement of one or more characteristics in an unbiased manner andwith a known degree of precision.The characteristics are measured by chemical analysis or physicaltesting or both.The sampling methods described are applicable to slurries that require inspection to verify compliancewith product specifications, determination of the value of a characteristic as a basis for settlementbetween trading partners or estimation of a set of average characteristics and variances that describesa system or procedure.Provided flow rates are not too high, the reference method against which other sampling proceduresare compared is one where the entire stream is diverted into a vessel for a specified time or volumeinterval.This method corresponds to the stopped-belt method described in ISo 13909-2.
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document(including any amendments) applies.ISO 20904 pdf download.