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The [[Wilfley table]] is a type of shape/density separator and is used extensively to separate zircons for U-Pb dating, or heavy minerals (e.g native gold) for commercial use. | The [[Wilfley table]] is a type of shape/density separator and is used extensively to separate zircons for U-Pb dating, or heavy minerals (e.g native gold) for commercial use. | ||
==Sample processing== | |||
After adjusting the shaking table to the right tilt angle and reciprocating movement speed (Stroke Speed, rpm), the sample is placed in the vibratory feeder which is feeding the table at a constant feed rate through the feed box (see figure). The sample is then divided into three fractions: | |||
• Heavy fraction | |||
• Middle fraction | |||
• Light fraction | |||
==Preparing for Operation== | ==Preparing for Operation== | ||
• Turn on the wash water and ensure that the water is running evenly over the deck and is free of any dry patches. Start the machine and run for a few minutes on water only to wet all table edges. | • Turn on the wash water and ensure that the water is running evenly over the deck and is free of any dry patches. Start the machine and run for a few minutes on water only to wet all table edges. | ||
• Prepare the table feed by mixing the dry solids with water to give a 25% solids by weight mixture. | |||
• Place all sample buckets under the product off takes. | |||
• The feed material will also respond better on the table if the feed has been sized beforehand so that all particles are in a narrow size particle band. | |||
• This avoids coarse “lights” reporting with fine “heavies” (Stokes Law) and therefore gives better separating performance. | |||
==Table tilt== | |||
• The angle of tilt is adjusted by slackening the M16 nut at the drive connection (24mm Spanner). This will release the deck and it can be adjusted to the angle required (See figure). | |||
• The correct slope can only be determined by visual inspection of separation. However, as a general rule, the greater the slope the cleaner the concentrate grade and lower the recovery and vice versa. | |||
• The angle of the table from feed to concentrate end can be adjusted using the hand wheel located under the support beam at the concentrate end of the table (See figure). This angle can only be optimised by trial and error. However, the higher the concentrate end the longer the material remains on the table. | |||
==Wash water== | |||
• The wash water which comes out from the wash sprays should flow evenly over the deck (see figure). The quantity of wash water can only be determined by experimentation. Higher wash water volume results in cleaner concentrates and lower recovery and vice versa. | |||
==Feed rate== | |||
• Feed rate is a function of particle size and specific density differences between particles. This can vary from a few kgs/hour upwards. However, as a general rule, the finer and/or more close density the separation between particles the lower the feed rate will be. (Typical max. 70 kg/hour) | |||
[[Kategorie:Alle Methoden]] | [[Kategorie:Alle Methoden]] |