Reason for lumps formation in rotary kilns of iron pelletizing plant - Crushing, Screening & Conveying - Metallurgist & Mineral Processing Engineer

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Reason for lumps formation in rotary kilns of iron pelletizing plant (6 replies and 3 comments)

3 years ago

Hello good time - Thank you for answering some of my questions

One of the main problems in rotary kilns in pelletizing plants
 is the presence of chunks or waste materials

1. What is the main reason for the formation of lump?
2. What is the proposed solution to reduce the chunk?

What do you think is the best solution to eliminate this problem?

alitorabi1369

3 years ago

alitorabi1369 3 years ago

this is chunk or waste

alitorabi1369

3 years ago

alitorabi1369 3 years ago

chunk

https://www.911metallurgist.com/wp-content/uploads/2021/10/12.jpg

Mike

3 years ago

Mike 3 years ago

1 like by David

Normally the goal is to prevent this not create them. They come from build up on the surfaces of the pelletizing equipment that falls off due to weight. This is one of the reasons you periodically shut down to clean out the system. The come from uneven mixing and imperfections on the walls.

alitorabi1369

3 years ago

Exactly, but what are the main reasons for the formation of this mass in the furnace? What is the solution to reduce the amount of this mass in the rotary furnaces?
What causes Chank formation?

David

3 years ago

David 3 years ago

On a copper concentrate rotary kiln dryer, I had welded a 100 mm diameter pipe on the outside. The pipe was about 60-70 cm long and elbow-shaped. About 30 cm perpendicular with the kiln's wall/shell and then 90 degrees for another 30 cm or so.

Inside the pipe, I place a 90mm steel grinding ball.

As the kiln rotated, the ball would roll into the pipe and knock the kiln wall. This did help heavy concentrate build-up to form inside the kiln.

I had these "rolling ball hammers" installed every 1.5 meters along the kiln's length.

https://www.911metallurgist.com/wp-content/uploads/2021/10/self-cleaning-a-rotary-kiln.png

David

3 years ago

I suspect the formation or caking comes from the feed material being must too wet. Review the upstream filtration performance. Over flocculation and other variables.

alitorabi1369

3 years ago

Thanks for your comment
The length of the furnace is 46 meters and iron is used in the pelletizing plan. Your mechanical idea is interesting, but the inner shell of the furnace is made of refractory bricks, which I think your idea is not applicable.

I searched a lot but did not find any results
Scientifically, chemically, metallurgically, what causes lumps in rotary kilns in iron pelletizing plants.
Please explain more. What factors should I consider
What solution do you suggest ?

David

3 years ago

David 3 years ago

Can you show us what the material looks like before it enters the kiln?

What are the operational steps before the kiln? Is it a filter of some type? Before that, what do you have?

Mike

3 years ago

Mike 3 years ago

As said before and implied in David's comments, a main cause is in the pelletizing stage where the pellets are created. Normally you would have a classification step between the pellet formation and the calcination steps, both to remove large chunks and undersize material.

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