Concrete reclaimer — poor separation, stalled screws and thick slurry
Symptom
Sand comes out with the stone, stone reaches the slurry tank, sand is too wet, the washing screw stalls, slurry density is too high, or the slurry pump blocks.
Likely causes
- Screen mesh torn or blocked, or too much feed at once.
- Washing or dewatering screw flights worn.
- Screw tail bearing seized after its seals let water and grit in.
- Agitator stopped or weak, so the slurry settles.
- Lines not flushed before a stop.
Most likely and cheapest to check first.
Checks
- Daily - agitator running, density reading, spray nozzles clear, stone and sand discharging.
- Weekly - screw flights and tail bearing, screen mesh, pump, drive belts and hydraulic hoses.
- Monthly - check the density meter against a manual test (weigh a known volume).
Fix
- Repair mesh panels; reduce the feed rate.
- Hard-face or replace worn flights; replace the tail bearing with its seals.
- Keep the agitator running; inspect blades.
- Flush lines and screws at the end of every shift; keep the back-flush working.
Stop the equipment if
A screw is jammed. Lock out before clearing - never clear a jam with the screw running.
Parts you may need
If the agitator stops, the slurry sets
If the agitator stops for a few hours, the slurry settles and sets around the blades and the pump inlet. Restarting can be impossible without digging the tank out. Recycled water used as batch water must meet your concrete standard (in Europe, EN 1008); correct the mix for its solids.
DANGERSlurry pits and settling ponds cannot support a person. Fence or cover them; no lone working. Slurry is alkaline - gloves, goggles, waterproof clothing.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer