Hot Air Direct Fired Rotary Dryer - Drying Small Fish Waste

Pass your scales through a hammermill. If they are truly dry, they should break up. This was the process I used making fertilizer from leather scraps, using the same large dryer.

thanks but may i write to tell you that the material coming out of the drier is subsequently hammer-milled. The fish scales which consist of chitin do not breakeven after hammer milling..and when mixed in poultry feed get stuck in the throats of chicks...moreover please note that fishmeal is not to be powdered but should be ground to a granular consistency and scales unless cooked will do not disintegrate. When cooked in a pressure cooker or digester they simply melt and get almost ruined and hard to discern

Scales are just like organic nails, dry and chitinous.

You may have to experiment with different equipment, like a coffee grinder, a flour mill, or a different size hammermill.

Let me explain again, it is not the problem with grinding but rendering fish scales into meal. Since fish scales are integral part of fish they have to be rendered jointly. While doing this the fish is rendered but not the scales. What to do??

you may have to add a secondary gringing mill after the first process. screen out the fish meal from the first process leaving only the scales to go into the secondary gringer.

I tried this too but to no avail.

The real problem is not getting rid of the scales but how to put them to beneficial use by rendering them with the waste fish. Digesting fish scales in a digester or retort melts them down completely but drying down this 'super-saturated' cooked fish mass entails more problem in that it sticks to the walls of the rotary dryer and burns out the minerals in it. Moreover, increasing stages of production are not worth the effort as they reflect on the product cost. I think there should be some single-stage process to render fish waste into fishmeal through simultaneously cooking and drying in one go. Can anyone possibly tell??

I may be way off base ,but what if you freeze dried the product then ground while still frozen. seems you may get the proper texture.

That would be too costly and not viable at all in view of the fact that

the dryer is meant for drying more than 40 metric tons of semi-dried trash fish per day

!