Overview
SIST ISO 8858-2:2005 establishes a standardized laboratory procedure for the froth flotation testing of fine hard coal, specifically for coal particles smaller than 0.5 mm. Developed by the Slovenian Institute for Standardization (SIST) and mirroring the ISO 8858-2:2004 framework, this standard guides users through a sequential evaluation process. The core aim is to determine flotation characteristics, typically expressed as a yield/ash relationship, that a specific coal may demonstrate during froth flotation. This yield/ash curve is essential for assessing the quality and potential recoverability of fine coal fractions in coal preparation processes.
This standard is intended for laboratory testing and does not provide data suitable for direct plant design purposes. Samples that cannot be dewatered without heat or chemicals, as well as flotation kinetics investigations, fall outside its scope.
Key Topics
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Sequential Evaluation: Outlines a step-by-step laboratory procedure where a single fine coal sample undergoes a series of flotation and reflotation steps. Each stage seeks to produce concentrates and tailings, the properties of which build a comprehensive flotation response curve.
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Sample Preparation: Stresses the importance of consistent sample preparation methods, including particle size analysis and moisture determination. Sample history and handling should be documented, and ISO 13909-4 and ISO 1953 are referenced for preparation and size analysis.
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Flotation Conditions: Specifies variables such as collector and frother dosage, solids content, air flow rate, and temperature. Careful adjustment of these parameters helps generate accurate yield/ash relationships.
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Analysis and Reporting: Each test yields various fractions, all of which must be dried, weighed, and analysed for ash and moisture content. The data are then organized into tables and plotted as yield versus ash curves, enabling a clear understanding of the flotation performance.
Applications
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Coal Quality Evaluation: The resulting yield/ash curve is a powerful tool for characterizing how a given coal responds to flotation, aiding in decisions about its suitability for cleaning and beneficiation by froth flotation methods.
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Process Optimization: Enables laboratories to compare different coals, flotation reagents, or preparation procedures under controlled, repeatable conditions, supporting process development and research in coal preparation.
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Benchmarking: Standardized procedures provide a reliable foundation for benchmarking coal samples and research findings across labs and organizations involved in solid mineral fuels.
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Support for Coal Preparation Plant Development: Though not intended for direct plant design, sequential evaluation data help engineers and researchers understand the boundaries of achievable coal cleaning, informing higher-level process decisions.
Related Standards
- ISO 8858-1:1990 - Hard coal - Froth flotation testing - Part 1: Laboratory procedure (basis for apparatus and general procedures).
- ISO 589:2003 - Hard coal - Determination of total moisture.
- ISO 1171:1997 - Solid mineral fuels - Determination of ash.
- ISO 1213-1:1993 - Solid mineral fuels - Terminology - Part 1: Terms relating to coal preparation.
- ISO 1953:1994 - Hard coal - Size analysis by sieving.
- ISO 13909-4:2001 - Hard coal and coke - Mechanical sampling - Part 4: Preparation of test samples.
- ISO 7936:1992 - Hard coal - Determination and presentation of float and sink characteristics - Directions for apparatus and procedures.
Practical Value
By adhering to the SIST ISO 8858-2:2005 standard, laboratories and coal research facilities ensure consistency, reproducibility, and international comparability in froth flotation testing of fine coal. This sequential evaluation method delivers in-depth insight into yield and ash trade-offs, enhancing decision-making in coal quality assessment and process improvement efforts.
