1. Laboratory model sieve shaker various mesh number.
2. Weighting Machine
3. Pan etc.
Mineral Used: 100 gm of coal powder
Sieve analysis is more commonly known as screening. After crushing the raw material, the product obtained is very fine powder of desired size. The principle behind the screening process is differential separation of particles of sample based on size and shape.
Sieves are arranged in descending or ascending order of the mesh size. The various screen technique are Hand Screening Automatic Screening
Wet and dry Screening
In the experiment we use automatic screening number of different automatic screen machine which are available. The machine causes a circular motion of material on screen and a below is delivered to the sieves. Once for each revolution, the frame doesn’t over load screen. It gives good result for dried materials only.
Screening process is divided in to two stages. The test sieves are designated by normal aperture which is ideal diameter of round roles of sieves.
Different types of test screening are:
Taylor standard used in USA
British standard sieves
All these sieves are designed by mesh numberMesh Number:
Mesh number is defined as the number of sieves/ openings per liner inch.
Importance of Sieves Analysis:
1. It determines quality of grinding process.
2. It gives data regarding degree of liberation of valuable minerals. Efficiency of machine is known by knowing the output and can be controlled.
The powder sample is first weighed accurately to 100 gm and then sieves are arranged properly with the pan at the bottom end sieve no BS40 at the top. The sieve with powder is properly packed and proper stirring required and after 15 minutes the sieves are taken out. All the powder gets distributed according to the size distributionResult: Sieves analysis of a given sample of material (coal powder) is obtained and graph plotted shows that particles get distributed according to the size range of sieves used.
Particle gets distribution according to their size which in turn indicates how efficient the process is i. e. grinding process. It also tells us the degree of liberation. One of the hindrances to perfect the sieves analysis is adherence of extremely fine particles to coarser particles or to each other through
electrostatic action or because of moisture or dried salts.