Waterproof adhesive or glue, how to make a glue/adhesive Waterproof! Urgent Please!

Waterproof

Hi all, I hope to get some help from you here.
I'm a quality engineer working for a coal briquettes company in Turkey. What we do is collecting the coaldust from all over Turkey and make them briquettes by pressing under high pressure (70-80 bars).
We add some extra binder materials to the coaldust to get extra mechanical strength (%2 CMC-Cellulose by weight) and some water to make the coaldust compressible.
But our briquettes are not durable under rain. I mean our coal briquettes turn into dust in a few minutes under rain, that's just because of our binder. Cellulose is soluble in water.
But we need to produce highly durable briquettes under rain because we sell these products to industry and the briquettes are being stored at the outside of the factories.
That means we need a non-toxic, cheap and waterproof binder or adhesive to use with the coaldust.
Last week I tried to use Technical Gelatin. We all know Gelatin is made from protein. Maybe we can find a way to make Gelatin waterproof. Or an other way to produce waterproof briquettes. Anyone to help me???

chemisttree

Have you tried 5% cornstarch? You might try alginate instead of gelatin followed by lime treatment (spray) of the green body before drying. If you add enough lime, it might even help with sulfur emissions if the coal is of the high sulfur variety. You might also try a dilute glutaraldehyde spray of the wet green body when you use gelatin as well.