What is float-and-sink test for coal?
Float-sink tests are done on samples of coal from beds that will likely need washing (beneficiation, preparation) to remove sulfur or ash (rock and mineral matter) from the coal to meet the desired specifications of the end user.
What is the sink float method?
The float-and-sink method helps in separating coal samples according to the difference in their respective specific gravities in a heavy liquid medium. This heavy fluid separation method is independent of the particle size and only a function of the difference in the densities of two substances.
What is use of float-and-sink method?
When a Sink-Float is swirled in a liquid and thoroughly wet, it will either float in a more dense medium, sink in a less dense medium or stay suspended when the densities match. Continuous monitoring of liquid densities is performed by keeping a Sink-Float in the liquid.
What is washability characteristics of coal?
Washability analyses for selected coal samples using heavy organic liquids with a density from 1.3 to 2.0 g/cm 3 was carried out. The obtained washability curves indicate that a 30- 50% ash reduction with a 10-20% loss of combustible organic component could be achieved with a gravity separation.
What is coal density?
Coal is slightly denser than water (1.0 megagram per cubic metre) and significantly less dense than most rock and mineral matter (e.g., shale has a density of about 2.7 megagrams per cubic metre and pyrite of 5.0 megagrams per cubic metre).
Why coal washing is required?
According to industry calculations, coal washing improves the quality of coal by reducing the ash content to 33 per cent from an earlier 40-45 on an average for Indian coal. It also said “washing leads to reduction in the calorific value of the coal as well”.
Can all liquid mixtures be separated by floating and sinking?
You probably know that when solid objects are placed in liquid, they can sink or float. But did you know that liquids can also sink or float? In fact, it is possible to stack different layers of liquids on top of one another. The key is that all the different layers must have different densities.
Will potash borosilicate sink or float?
The potash borosilicate glass has the same density as the solution it is immersed in, so it will neither sink nor float.
Does charcoal sink or float?
Wood charcoal, which means the wood which is burnt to obtain charcoal, is not denser than water. It is lighter than water and thus floats on water.
What is difference between floating and sinking?
An object floats when the weight force on the object is balanced by the upward push of the water on the object. If the weight force down is larger than the upward push of the water on the object then the object will sink. If the reverse is true then the object will rise – rising is the opposite of sinking.
What is washing of coal describe washability curve in detail?
A curve or graph showing the results of a series of float-and-sink tests. Washability curves are essential when designing a new coal or mineral washery. There are four main types of washability curves: characteristic ash curve, cumulative float curve, cumulative sink curve, and densimetric or specific gravity curve.
What are 4 types of coal?
Coal is classified into four main types, or ranks: anthracite, bituminous, subbituminous, and lignite. The ranking depends on the types and amounts of carbon the coal contains and on the amount of heat energy the coal can produce.
How are float and sink tests used in coal analysis?
In washability tests, coal samples are separated into float and sink fractions in liquids of increasing density. If a coal sample will be sent to a preparation plant that uses a fixed density for separating coal from rock and minerals, then a single float-sink test may be done on a sample at the fluid density used in the plant.
Can a float and sink be done on air dry coal?
Float and sink analysis is traditionally done on air-dry samples. Commercial coal preparation, however, is carried out on wet coal. The density of an air-dry particle, in a float and sink liquid, is different from the density of a water saturated particle in a washery dense medium.
How is a float / sink analysis performed on a sample?
During the test, your sample is characterized and quantified as low-density clean coal, high-density reject or intermediate-density middlings. Our float/sink analysis can be performed on samples ranging in size from bulk washability samples (over 1 ton) to bench-scale size samples.
Who is the world leader in Float Sink testing?
SGS is a global technical leader in float-sink/washability testing. Our experienced staff are located in major coal producing regions around the world and will give you accurate and impartial results. Independent SGS test results are recognized globally and comply with all applicable international standards.