Crushing, Screening & Conveying

Crushing, Screening & Conveying 2017-03-23T09:38:14+00:00
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Screening Efficiency (6 replies)

anjanisail
2 months ago
anjanisail 2 months ago

Dear all

In our Steel Plant to remove fines from Lump in iron ore, one Double deck screen is installed and is working, but with very poor efficiency. All the top and bottom deck are of Polymer panel. Top panel opening is 22mm sq. aperture and bottom deck aperture is 12mm sq. aperture. But still after screening lot of undersize is coming in Lumps, this causes deterioration in the quality of lumps which is being fed to blast furnace.

Action required to increase the screening efficiency with the same screen may be : (1) change Polymer panel by Poly ripple mesh (2) To make a dam on the bottom deck to increase the particle settling time.(3) To play with the vibration - amplitude of screen (4) At last we can change the screen

Please give the appropriate suggestion to improve the screening efficiency.

ThabisoKwenane
2 months ago
ThabisoKwenane 2 months ago
2 likes by Jean Rasczak and David

One of the things that you can try to do is to increase the length of your screen by 30% of its current length size to aid in increasing your residence time, Ensure that your screen inclination angle is in the range of 5 to 10 degrees to have a reasonable bed height, also do try applying reverse elliptical movement on both of your screens. Ask your screen supplier if they can manage to sell or manipulate your current screens to that kind of movement. Good luck.

dk
2 months ago
dk 2 months ago
1 like by David

The screening efficiency is poor because of overloading  of screen deck or higher moisture level. You may check the  sieve analysis of feed and may redesign the upper deck screen aperture. If problem still there, on a trail run reduce the  feed capacity and see the efficiency and if reuire may have to provide another parallel screen.

Philip Stewart
2 months ago
Philip Stewart 2 months ago
1 like by David

Whilst polymer panels are attractive in terms of not being subject to corrosion and being wear resistant they have a very poor open area compared to metal screens and the openings can flex decreasing the accuracy of the screen.  Try a metal screen, you may well find that not only will a much higher percentage of open area help but the more rigid surface may help break up agglomerates.

 

anjanisail
1 month ago
anjanisail 1 month ago

Lot of thanks for reply. In continuation of above I like to know how one
can change the G force of an screen which is in operation in plant. What
are the probable options to vary throw/stroke/frequency of a screen which
is in operation. How we will optimize the combination of
throw/stroke/frequency for manipulating the G force.

 

Stewart Fernandez
1 month ago
Stewart Fernandez 1 month ago
1 like by David

Hi, please read the two papers I have put together:

https://www.linkedin.com/pulse/getting-your-cross-tension-screens-operating-peak-stewart-fernandez?trk=mp-reader-card

https://www.linkedin.com/pulse/screening-guide-stewart-fernandez?trk=mp-reader-card

3 https://www.911metallurgist.com/blog/screening

what is the size of the screen deck - picture of the decks - straight after stopping - what is the feed rate  - what is F 80- ( 80 percent of the feed to the top deck ) - what is the moisture content of the material feeding

there are many solutions to your problem, email me (I will send you the questionnaire to be completed), so that I can post a response here for all to learn.

lordi
1 week ago
lordi 1 week ago

You can use steel wired deck. Best efficiency will be on steel wired surface. But this type of deck is wearing faster.

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