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BS ISO 502:2015 pdf free

BS ISO 502:2015 pdf free.Coal一Determination of caking power一Gray-King coke test
The sample is heated under standard conditions to a final temperature of 600 °C. The coke residue obtained is classified by reference to a series of standard residues. If the coke residue produced is so swollen that it fills the cross-section of the retort tube, the determination is repeated with the coal admixed with a suitable quantity of electrode carbon or equivalent material. For these highly swelling coals, the Gray-King coke type is defined by the minimum amount of electrode carbon required to produce a strong hard coke residue of the same volume as the original coal and electrode carbon mixture.
Furnace, horizontal electric, 50 mm internal diameter and 300 mm long, with one end closed and the other carrying a plug of insulating material which is bored centrally with a hole 25 mm in diameter.
The winding of the furnace shall be such that the middle 200 mm is at a uniform temperature within ±5 °C at both 300°C and 600 °C. Alternatively, the furnace may be constructed from an electrically-heated aluminium-bronze block, with one or several, bores of 25 mm diameter. The furnace shall be insulated and located in a cover of metal or other suitable material, and shall be equipped with a suitable thermocouple,lying above the retort tube when the latter is in position and with the junction at the centre of the furnace.
An indicator shall be provided for showing the furnace temperature with an accuracy of±5 °C. A suitable means of controlling the energy input shall also be provided to permit an increase in temperature ata rate of 5°C/min. A multiple tube furnace to allow simultaneous determinations is convenient. The furnace may be of the fixed type or mounted on rails. Suitable furnaces are shown in Figure 2 and Figure 3.
Retort tube (see Figure 4), a heat-resistant glass or transparent silica tube, 20 mm internal diameter and 300 mm long, closed at one end, with a side arm, 8 mm internal diameter and 50 mm long, sealed in at a distance of about 20 mm from the open end. The tube shall be smooth and either of uniform bore or with a slight taper (19 mm to 21 mm) such that the open end is the larger.BS ISO 502 pdf free.

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