ISO 8858-1:2019 pdf free.Hard coal一Froth flotation testing – Laboratory procedure.
6 Apparatus
The apparatus shall be a mechanical impeller type flotation machine (see Figure 1) with the following
specifications.
6.1 Flotation cell manufactured from stainless steel.
Figure 2 shows the dimensions of the flotation cell. The capacity of the cell with the deflector block and impeller in place is approximately 3,5 1.
It has been shown that the results obtained from laboratory froth flotation tests are very dependent on the procedure used to remove the concentrate from the surface of the pulp. For this reason, a deflector block manufactured from plastics material (see Figure 3) is used to guide the concentrate to a rectangular area in front of the impeller housing. The concentrate can then be removed by means of a scraper (see Ftgurv4) which is designed to cover the full width of the cell to a constant depth.
In order to establish the volume of pulp which can he contained in the flotation cell, the deflector block is fitted into the cell and water is added to the flotation cell to about 20 mm to 30 mm below the required pulp level. The impeller is started (air valve off) and additional water is added to the required mark (see &4). The impeller is stopped, the deflector block removed, and the volume of water in the flotation cell is measured.
6.2 Impeller assembly, of stainless steel and capable of rotation at frequencies up to 1 500 revolutions per minute (equivalent to a speed of 5,7 rn/s at the periphery). The dimensions of the impeller and diffuser arc shown in Figures S and 6.
The lower face of the impeller shall be positioned no more than 5 mm from the base of the cell.
Impellers constructed of other materials may be used, provided that it can be shown that the characteristics of flotation for the cell are similar to those obtained when a stainless steel impeller is used. To achieve this, different impeller rotational frequencies may he used if necessary.
6.3 Constant level control, maintaining the level of the pulp in the cell during the flotation test.
6.4 Scraper, of the design shown in Figure 4. Its clearance at the sides of the cell shall be minimal and should not exceed 2 mm. The scraper shall he of such dimensions that it clears the pulp level (as defined in &4) by not more than 2 mm.
6.5 Calibrated micro-syringe, for the addition of the collector (Si.).
6.6 Pipette, of capacity 25 ml, complying with Iso 648, for the addition of the frother solution (52).
6.7 Timing device, accurate to I s and capable of being zeroed and started as required.
6.8 Test sieves, complying with Iso 565, for the particle size analysis of the feed.
7 Sampling
The history and method of preparation of samples can affect considerably the flotation characteristics of the coal. The origin of the sample should be recorded and care should be taken to ensure that samples for comparison purposes are prepared in a similar manner. Since repeat tests are required together with sub-sampling for particle size and moisture determination, great care should be taken in mixing and subdivision of the original sample. Where applicable, all sampling and subdivision of samples shall be carried out in accordance with the procedures specified in ISO 13909-1 to ISO 13909-4 and ISO 18283 as appropriate.ISO 8858-1 pdf download.