ISO 4700:2015 pdf download

ISO 4700:2015 pdf download.Iron ore pellets for blast furnace and direct reduction feedstocks — Determination of the crushing strength
1 Scope
This International Standard specifies a method to provide a measure of the compressive load attained to cause breakage of pellets.
This International Standard is applicable to hot bonded pellets.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 11323, Iron ore and direct reduced iron — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11323 apply.
4 Principle
A single pellet of a specific size range is compressed at a specific speed. The procedure is repeated on all pellets in the test portion. The crushing strength is calculated as the arithmetic mean of all the measurements obtained.
5 Sampling, sample preparation and preparation of test portions
5.1 Sampling and sample preparation
Sampling of a lot and preparation of a test sample shall be in accordance with ISO 3082.
The size range for pellets shall be −12,5 mm +10,0 mm.
A test sample of at least 1 kg, on a dry basis, of sized pellets shall be obtained.
Oven-dry the test sample to constant mass at 105 °C ± 5 °C and cool it to room temperature before testing.
NOTE Constant mass is achieved when the difference in mass between two subsequent measurements becomes less than 0,05 % of the initial mass of the test sample.
6.2 Loading unit, formed by two compressive flat platens made of steel, installed in mutual parallel planes. The surface of the platens that will be in contact with the sample shall be made of surface- hardened steel. A device capable of setting the speed of the compressive platen between 10 mm/min and 20 mm/min over the entire test period shall be used. NOTE If the platen speed is not constant during the test cycle, results may differ depending upon the test machine used. More uniform results may be obtained using a test machine that applies a constant load increase.
6.3 Load transmission system, which shall be either a load cell or a lever. The capacity of the load cell for transmission of the applied load to the indicating unit shall be at least 10 kN.
6.4 Load indicator or recorder, which shall be either an electric indicator (digital read-out device, recording chart, meter with needle rider or other suitable device) for the load-cell type, or a mechanical indicator (gauge equipped with a needle rider or other suitable device) for the lever type. When using a load cell, the chart-recorder pen-response time shall be 1,0 s or less for a full-scale deflection. The minimum graduation shall be 1/100 of the full scale. The compression device shall be calibrated regularly.