Impregnating bulk solids with liquids

I would define impregnating as applying a liquid additive into an absorbent powder or granule. The adaptability of “Free-Fall Processing®” is even more evident when you consider we have some customers who spray as little as ¼% liquid into a carrier and others apply as much as 70% liquid into highly absorbent precipitated silica. Every porous particle has its own level or threshold of liquid it can absorb called insipient wetness. This is the point where it cannot take any more liquid and becomes a wet slurry.
One of the best examples of impregnating granules is common in the Agricultural Chemicals industry. The leading manufacturer of Fire Ant Bait in the United States uses the Continental Rollo-Mixer® to impregnate granular carriers with an insecticide. It is important that the liquid AI (Active Ingredient) is evenly sprayed throughout all of the surface area of the carrier, so that the COA’s (Certificate of Analysis) are consistent and on target. The AI’s are so potent and concentrated that they measure final product analysis in parts per million.
The assay called for 50ppm + or – 10%. In each of the four batch’s we ran, the granular carrier was loaded into the top of the Rollo-Mixer® from a super sack, impregnated with the insecticide solution, sampled, and then discharged back into a super sack. The lab results were exceptional: Batch 1. = 48 ppm. Batch 2. = 49 ppm. Batch 3. & 4. = 51 ppm. “Free-Fall Processing®” enables our customers to deliver the exact amount of AI into the carrier without having to over formulate or rework the product.