BS ISO 12742:2020 pdf download

BS ISO 12742:2020 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 .iso .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.