The goal of mixing is simple: to get raw materials of different origins and properties to "harmonize." The solution offered by the fertilizer horizontal mixing machine is "convection." Angled paddles or spiral ribbons are fixed to a horizontally mounted mixing shaft; as it rotates, the material moves simultaneously in both axial and radial directions. The outer spiral ribbon pushes material from the ends toward the center, while the inner ribbon pushes it from the center toward the ends, creating a reciprocating convective cycle. A well-designed horizontal mixer can achieve a statistically uniform distribution of granules with vastly different specific gravities within minutes, all while causing virtually no damage to the granules' original shape.

The organic fertilizer double-shaft mixer, however, faces a different set of challenges: organic fertilizer raw materials often have high moisture content, are highly fibrous, and tend to clump. Its solution is "counter-rotation." Two parallel mixing shafts rotate in opposite directions; as the paddles turn, they toss the material upward, generating a combination of convective, shear, and diffusive movements within the mixing chamber. Crucially, the counter-rotating shafts scrape against each other during the meshing process, effectively preventing wet material from wrapping around or clinging to the shafts. For organic materials fresh out of the fermentation tank and still retaining moisture, this "self-cleaning" capability is virtually essential—otherwise, the downtime required for cleaning could easily exceed the time spent actually producing.

The dryer for organic biological fertilizer addresses the "last mile" challenge of the granulation process: granules fresh out of the granulator typically have a moisture content of 20% to 40%; if bagged immediately, they will become moldy and clump together within a month. The operating principle is straightforward—hot air passes through a tumbling bed of granules, carrying away excess moisture—but the real difficulty lies in control. Excessive temperatures can destroy nutrients on the granule surface (urea, for instance, begins to decompose above 60°C), while insufficient heat fails to remove enough moisture. High-quality dryers feature temperature and humidity sensors at both the inlet and outlet that provide real-time feedback to the control system, allowing for dynamic adjustments to the hot air temperature and retention time.