Granular organic fertilizer plant
Granules sell at a premium because they can be spread by machine, stored without caking and packed attractively. The premium is earned by controlling
01
Targets and test methods
| Parameter | Target | Method | Sampling frequency |
|---|---|---|---|
| Size distribution | 80% within 2–4 mm | Sieve set (e.g. 1, 2, 4, 6 mm), 500 g sample | Per shift |
| Crushing strength | 8–15 N per granule | Manual or bench granule strength tester, 10 granules | Per shift |
| Moisture | 12–14% | Oven at 105 °C, or calibrated moisture meter | Per shift and per batch |
| Fines after handling | < 5% | Sieve a bagged sample after the normal handling route | Weekly |
| Bulk density | ± 5% batch to batch | Filled container of known volume | Weekly |
02
What to change when granules are off target
| Symptom | Process causes | Adjustment |
|---|---|---|
| Too many fines | Binder too low, feed too dry, recycle ratio too low | Increase binder, raise moisture slightly, increase recycle |
| Oversize granules | Residence time too long, disc angle too steep, feed too wet | Reduce residence, adjust angle, reduce binder water |
| Weak granules | Insufficient binder, over-fast drying, low granule density | Increase binder, reduce drying rate, check granulator speed |
| Caking in store | Moisture above 14%, insufficient cooling, no coating | Reduce final moisture, check cooler duty, add coating |
| Dust in the bag | Screening cut too coarse, excessive drop heights, coating absent | Re-check screen mesh, reduce drop heights, consider coating |
03
Why moisture control dominates granule quality
Granulation is a delicate balance around a narrow moisture window: too dry and the material will not agglomerate, too wet and it forms paste instead of granules. Because cured material moisture varies with weather and feedstock, the plant either controls moisture upstream or chases granulator settings all day.
The practical rule is to control moisture before the granulator, not in it: use consistent curing, screening and blending, and add water only as the final trim. Plants that treat the granulator as the place where moisture is corrected produce variable granules and consume excessive binder.
Check your granule quality
Send your size distribution and strength results; we will identify which process setting is most likely responsible.
FAQ
Plant engineering questions
What granule strength does organic fertilizer need?
Enough to survive bagging, stacking and transport: commonly 8–15 N per granule for organic products. Products that are coated or bound with mineral additives can be stronger, but organic-only granules are naturally softer than mineral fertilizers.
Why does my product cake in the bag?
Moisture above 14%, insufficient cooling before bagging, or a lack of anti-caking coating. Caking usually starts at the bag wall where condensation forms, so bag temperature matters as much as product moisture.
How much of the product should be in my declared size range?
A common commercial target is 80% within the declared range. The remaining 20% is split between oversize, which is crushed and recycled, and fines, which return to the granulator.
Send us your design basis
Tell us the feedstock, the daily tonnage and the product you want to sell. The engineering team replies with the plant configuration, the equipment scope and the information we still need before layout drawings start.
- Feedstock profile — type, moisture, contamination, seasonal peaks
- Capacity — t/day fresh material or t/h finished fertilizer
- Product — powder, granules, bagged retail, bulk compost
- Site — available area, power supply, water, access road
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