AS ISO 12742 pdf download

AS ISO 12742 pdf download.Copper, lead and zinc sulfide concentrates — Determination of transportable moisture limits — Flow-table method
1  Scope
This document specifies a flow-table method for the determination of the transportable moisture limit (TML) of copper, lead and zinc sulfide concentrates, which can liquefy during transport. It is applicable to the determination of the TML of concentrates containing 10 % to 80 % (mass fraction) of lead, 10 % to 65 % (mass fraction) of zinc or 10 % to 55 % (mass fraction) of copper and is applicable to TML values in the range 3 % to 28 % (mass fraction).
2  Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 10251, Copper, lead, zinc and nickel concentrates — Determination of mass loss of bulk material on drying ISO 12743, Copper, lead, zinc and nickel concentrates — Sampling procedures for determination of metal and moisture content
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .org/ obp — IEC Electropedia: available at http:// www .electropedia .org/ 3.1 flow moisture point percentage of moisture at which a flow state is reached 3.2 transportable moisture limit maximum percentage of moisture that a cargo can contain during transport without the risk of liquefaction
4  Principle
The moisture content of the sample is adjusted by mixing with water. The mixture is converted to a conical shape using a mould and tamper. The sample is placed on the flow table and the mould is removed. The flow characteristics are determined by repeated dropping of the flow table while observing the behaviour of the sample. When sufficient water has been added to the sample so that plastic deformation occurs during the dropping of the flow table, the sample is considered to be at its flow moisture point. The TML is calculated as 90 % of the flow moisture point.
5  Apparatus
Copper, lead and zinc concentrates can gain or lose moisture rapidly when exposed to air. The laboratory should be designed so that excessive temperatures, direct sunlight, air currents and humidity variations are avoided. 5.1 Flow table and frame 1) , as specified in Annex A. The flow-table mounting shall be as specified in Figure A.1. 5.2 Mould 1) , as specified in Figure A.1. 5.3 Tamper 1) . The required tamping pressure can be achieved by using calibrated, spring-loaded tampers or some other suitable design of tamper that allows a controlled pressure to be applied via a 30 mm diameter tamper head as specified in Figure A.2. 5.4 Calliper ruler. 5.5 Balance, top loading, having the sensitivity specified in Table 1.5.6 Measuring cylinder, of capacity 50 ml to 200 ml. 5.7 Burette, of capacity 10 ml. 5.8 Mixing bowl 2) , hemispherical, of diameter approximately 30 cm. It is recommended that an automatic mechanical mixer having a mixing bowl as described is used, as this leads to improved precision. 5.9 Rubber gloves.5.10 Drying trays or pans, having dimensions that permit the sample to be spread to a thickness of less than 30 mm. The trays shall be made of corrosion-resistant and heat-resistant material, such as stainless steel, glass or enamel plate. 5.11 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of 105 °C ± 5 °C.
6  Sampling and sample preparation
6.1  General TML figures are required to be updated on a periodic basis, usually six-monthly, or when there is a known change to the process used to produce the material. The reported figure should be the mean of samples taken during the period. To ensure that the TML result is representative, increments of the material shall be taken in accordance with ISO 12743, either: a) while a stockpile is being built up or broken down; or b) while loading or discharging a vessel. These increments are combined to form the sample used to determine TML. The sample used to determine TML should not be used to determine moisture content. Stationary sampling of stockpiles should never be used for the determination of TML. This method of sampling can only be used to provide an indicative moisture value for use during the planning of shipping schedules.