AGGLOMERATION
When it is decided to agglomerate, get your objective clear in your head before proceeding. It needs to be understood what the primary objective is. Is it environmental, or could it be for cost savings? Agglomeration can also improve furnace performance. There are many reasons to agglomerate and it has been found that on occasions it can be possible to kill 2 or 3 birds with one stone. BUT do not get greedy, always remember the primary objective.
Once the objective is clear on why the agglomerate is required the next step is to set the criteria for the agglomerate. These are normally.
- A certain cold strength is required, so that the agglomerate does not break down in the raw material handling system feeding the furnaces. Do not go for overkill in the design, design for a worst case scenario.
- The material should have an adequate hot strength, so that it would be able to penetrate into the furnace burden without breaking down. It has been found that shape, chemical and physical composition of the agglomerate can assist with this hot strength.
- The material has to be correctly shaped and sized, in order to adequately move through the raw material transport system without blocking or slowing down feed systems. Shape will also contribute to the generation of fines in the agglomerate.
- Set a minimum and maximum requirement for chemical composition required within the agglomerate.
In selecting a binder, this is usually closely linked with mixing techniques, type of agglomeration, physical and chemical properties of the raw materials as well as possible contamination of the final product.
In the past experience has been obtained on the following agglomeration techniques.
- Pelletising.
- Micro-agglomeration.
- Brick Making.
- Briquetting.
- Extrusion
It was found that each has its place, dependent on end use of agglomerate, raw material type, cost and binder,