Physical-chemical parameters
Jutta Laine-Ylijoki, Markku Juvankoski, Tommi Kaartinen, Elina Merta, Ulla-Maija Mroueh, Jarno Mäkinen, Emma Niemeläinen, Henna Punkkinen & Margareta Wahlström, VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Finland.
Introduction
Every mineral deposit is more or less unique with regard to waste properties as well as to its geological, geographical, hydrological, climatic etc. conditions. This in turn leads to site specific designs of waste disposal facilities. What information on physical properties is needed and relevant will have to be evaluated based on characterization objectives and site specific conditions. A complicating factor is that particle size and many other physical properties of the waste cannot be assessed in detail prior to extraction, which means that the initial characterization will have to be followed up during operation. (Technical Committee CEN/TC 292)
Physical properties are important in the context of dam or slope stability assessment and may impact the geochemical behaviour of the waste as well as being impacted by chemical reactions taking place. The determination of physical-chemical parameters of extractive wastes may therefore be done for various purposes. There are numerous methods available for analysis of physical-chemical properties, e.g. water content, pH, conductivity and loss of ignition (LOI). Tables 1 and 2 comprise the results by CEN/TC 292, which has evaluated the applicability of existing CEN/TC 292 standards and work items for wastes of the extractive industries related to these parameters (Technical Comittee CEN/TC 292 2012).
Table 1. Methods for water content (Technical Committee CEN/TC 292 2012). See also Physical and geotechnical properties.
Parameter/method | Standard number and name | Applicable | Comment |
---|---|---|---|
Water content | EN 1097-5: Tests for mechanical and physical properties of aggregates – Part 5: Determination of the water content by drying in a ventilated oven | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | Result is given from a different basis. For wastes, solid mineral fuels (coal) and sludges the moisture content is calculated by dividing the moisture mass by the sample mass (i.e. dry plus moisture mass), while for soil and aggregates it is calculated by dividing the moisture mass by the dry mass. |
EN 12880: Characterization of sludges – Determination of dry residue and water content | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | ||
EN 14346: Characterization of waste – Calculation of dry matter by determination of dry residue or water content | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | EN 14346 and EN 15934 are basically the same. Preferred method. | |
EN 15934: Sludge, treated biowaste, soil and waste – Calculation of dry matter by determination of dry residue or water content | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | EN 14346 and EN 15934 are basically the same. | |
ISO 589: Hard coal – Determination of total moisture | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | ||
ISO 11465: Soil quality – Determination of dry matter and water content on a mass basis – Gravimetric method | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | see EN 1097-5 | |
CEN ISO/TS 17892-1: Geotechnical investigation and testing. Laboratory testing of soil – Part 1: Determination of water content | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | see EN 1097-5 |
Table 2. Methods for pH, conductivity and loss of ignition (Technical Committee CEN/TC 292 2012).
Parameter/method | Standard number and name | Applicable | Comment |
pH and conductivity* | EN 12176: Characterization of sludge – Determination of pH-value | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | The scope is limited to sludges. However, it includes solid sludges similar to the wastes classified here. Although not tested the method seems to be applicable. |
ISO 10390: Soil quality – Determination of pH | Not applicable to wastes from extractive industries for each type | Standard has too many options with many parameters possibly influencing the result. Methods have not been tested for tailings and waste rock/overburden. | |
EN 15933, EN 15937: Sludge, treated biowaste and soil – Determination of pH
Sludge, treated biowaste and soil – Determination of specific electrical conductivity |
Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | Standard to be validated. Preferred method. | |
ISO 11265: Soil quality – Determination of the specific electrical conductivity | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | ||
Loss on ignition |
EN 1744-1: Tests for chemical properties of aggregates – Part 1: Chemical analysis Article 17: determination of loss on ignition; T = 975°C | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | The 4 following standards use different temperatures for ignition (550°C to 975°C), which may give different results not validated |
EN 15169: Characterization of waste – Determination of loss on ignition in waste, sludge and sediments; T = 550°C |
Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | EN 15169 and EN 15935 are basically the same. Preferred method | |
EN 15935: Sludge, treated biowaste, soil and waste – Determination of loss on ignition (LOI), T = 550°C | Applicable to wastes from extractive industries for each type (i.e. tailings, waste rock, overburden and topsoil) | Standard in enquiry. | |
ISO 1171: Solid mineral fuels – Determination of ash, T = 815°C | Applicable to wastes from extractive industries for each type, but several restrictions have to be considered or methods are not yet validated. | see EN 1744-1 |
*pH and conductivity can be measured using standards listed in this table, but also the first eluate from leaching tests can be used to get an indication of pH and conductivity.
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