What is ISO 12742 - Flow-table method about?
ISO 12742 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.
ISO 12742 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).
Who is ISO 12742 - Flow-table method for?
ISO 12742 on the flow-table method is relevant to:
- Metallurgical engineers
- Hydrothermal engineers
- Corrosion engineers
- Processors of metals
- Testing authorities
- Calcium format manufacturers
- Manufacturers of hydro test equipment
Why should you use ISO 12742 - Flow-table method?
Zinc ores are widely distributed throughout the world. The common containing zinc-minerals are the zinc sulphide known as zinc blende.
ISO 12742 describes the addition of the graphical method for the determination of the flow point Aseans of validating the bracket method. ISO 12742 also describes the design of equipment suitable for determining the TML by the flow-table method. ISO 12742 assists the user with a flow moisture point that mines the percentage of moisture at which a flow state is reached. ISO 12742 also provides guidance on the transportable moisture limit which helps in determining the maximum percentage of moisture that o can contain during transport without the risk of liquefaction. Copper, lead, and zinc concentrates can undergo rapid changes in moisture when exposed to air, so all stages of the test should be accomplished in the shortest period and shall be completed within the day of commencement.
Overall, ISO 12742 is helpful as it guides on the TML figures that 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 figures are the mean of samples taken during the period.
What’s changed since the last update?
BS ISO 12742:2020 supersedes BS ISO 12742:2007, which is withdrawn.
BS ISO 12742:2020 replaces the second edition (ISO 12742:2007), which has been technically revised. The main changes to the previous edition are as follows:
- Clause 3, 'Terms and definitions', added
- 2: Reference to 7.4.4 for partial drying in event that sample received above transportable moisture limit (TML) added
- Clause 6: Reference to ISO 12743 sampling procedures added
- 3: Description of the flow state changed for clarity
- 4.2: Permission to deviate from the sample mass requirements of ISO 10251 for moisture determination added.
