Gravity Separation & Concentration Methods

Gravity Separation & Concentration Methods

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Feed capacity of the largest single deck shaking table (4 replies)

Treve Mildren
7 years ago
Treve Mildren 7 years ago

What is the realistic feed capacity of a large shaking table ? I know the stated tonnages on the sales data sheets are rather exaggerated so does anyone have any real world numbers?

What is the factor which decides that scale up? Logic would suggest the surface area but I am doubtful that is the case. Length would provide retention time but would not add to the capacity, so is it purely down to the width dimension?

Thanks in advance.

D
Deano
7 years ago
Deano 7 years ago
1 like by David

The capacity of a wilfley type table is dependent on a range of factors, each of which will affect the capacity.

Some of these factors are;

SG difference of cons and rest of feed, the greater the difference the larger the table capacity

Size range of feed and where the cons lie in the size range, the narrower the size range and the higher the cons are in the size range the greater the table capacity

How well the feed is sized, if sized with a top and bottom cut the capacity will be higher than with just a top cut. Having particles which should have been rejected whilst sizing in the feed will lessen table capacity

How well the table is set up for that particular separation i.e. side slope, rate of wash water addition,, how and where the wash water is added to the table, how evenly the feed is introduced to the table.

 

 

J
Jorge
7 years ago
Jorge 7 years ago
1 like by David

The capacity is variable and depends on several parameters or variable (e.g. stroke, particle size, wash water). Operating adjustments available on the standard table are length of stroke, tilt, wash water, location of product splitters. In small mills where irregularity in feed conditions is frequently the rule, control of all of these is necessarily left with the operator. The tendency in large mills is to limit operator's adjustments to tilt and wash water and in some mills tilt is not adjustable and the operator controls wash water only. In some plants splitters are fixed in position and products must be brought to the proper points by shifting their position on the table deck by changing tilt and wash water. It is much better to have movable splitters and to take care of all minor shifting of the product streams by moving the splitters, leaving water and tilt as nearly undisturbed as possible.

Separating auriferous pyrite from siliceous gangue, capacity is about 20 to 35 t per deck on 1 mm. sands, falling to 10 t on 0.1-mm. sands and rising to 45 t on 2-mm. material. Size of feed rarely exceeds 2.5 mm.

Slope varies with size of feed, specific gravity of minerals, character of products desired, and the place that the products are split, as well as with the quantity of wash water. The usual slope with fine feeds is from 1/4 to 1/2 in. per ft. and  3/4 to 1 in. with coarse feeds. When roughing the slope may be as much as 1 1/2 in. per ft

Speed may range from about 230 to 280 strokes per min., being close to 250 in the majority of mills. Length of stroke averages close to 3/4 in. Within the range of practice presented, no distinct relation between stroke length and speed is established, but in general a short stroke corresponds to a high speed and vice versa.

Lost time is very small and is principally due to shut-downs for replacing deck covering and repairing or renewing riffles. Mechanism difficulties usually correspond to high tonnages and long stroke or to attempts to run double decks with the standard head motion.

You should read the article written by Razaly and Veasy, Statistical Modelling of a Shaking table Separator, Minerals Engineering, Vol 3/4, pp 287-294, 1990

Treve Mildren
7 years ago
Treve Mildren 7 years ago

Thank you Deano & Jorge for your comprehensive replies. I will follow up on your advise and read the suggested article by Razaly & Veasy.

F
Firon Woo
7 years ago
Firon Woo 7 years ago

I know Chinese Shaking capacity ranges from 0.1-1.8mt/h of pulp. They never gave a solid capacity though.

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