Lime stabilization is a proven, straightforward path to Class B (and with supplemental heat, Class A) biosolids — but the material that leaves the mixer is a different animal from dewatered cake. It’s hotter, strongly alkaline, prone to scaling, and dustier. Conveyors specified for plain cake service often struggle the day lime addition starts.
How Lime Changes the Material
Quicklime hydration is exothermic: material temperatures rise substantially, and equipment sees sustained heat that standard belting and components may not be rated for. The high pH attacks aluminum and some coatings outright. Free lime dusts at transfer points and hydrates on any damp surface into scale that narrows chutes and builds on structure. And the material’s consistency shifts with dose and mixing — from granular to plastic — sometimes within one operating day.
Design Responses That Work
- Rate components for the real temperature: belting, wear surfaces, and anything in contact with fresh product should be specified against post-mixer temperatures, not ambient assumptions
- Choose lime-compatible materials: stainless contact surfaces and pH-tolerant belting; avoid aluminum anywhere product or dust reaches
- Minimize transfers: every transfer point is a dust source and a scale-formation site — a continuous-path Pathwinder conveyor from mixer discharge to storage or loadout removes the intermediate points where lime problems concentrate
- Contain and collect dust at the points that remain, and design chutes steep and smooth so material moves rather than lingers
- Plan for cleaning: scale happens; make every surface that develops it reachable and washdown-tolerant
Storage and Loadout
Lime-stabilized product frequently goes to cake storage or directly to trucks for land application. Even distribution matters at both: the Flight Distribution conveyor fills trailers or storage uniformly, avoiding the compacted single-point pile that lime product sets into if left standing.
If your facility is adding lime stabilization — or fighting the equipment consequences of having added it — the conveying system deserves a specific look. Send the process details through our free engineering review and Serpentix engineers will evaluate materials, routing, and containment against what lime actually does.
