Dust in NPK blending fertilizer production lines primarily originates from four main points: silo discharge, belt conveyor, mixing feed, and packaging discharge. Improvements in sealing, dust removal, process, and raw materials can significantly reduce dust emissions.

I. Complete Enclosure Modification of All Discharge Points

1. Install telescopic dustproof curtains and buffer guide troughs at the silo discharge outlet to reduce material drop height. For drop heights exceeding 50cm, add buffer chutes to prevent dust from splashing up from high altitudes. Install fully enclosed dust covers at the conveyor head and tail, and add material-blocking rubber strips on both sides of the conveyor belt to prevent side dust spillage.

2. Install sealing covers at the mixer inlet and inspection port, keeping them closed during NPK bulk blending machine operation and opening only for maintenance to prevent internal dust from spilling out during mixing. Install flexible connecting cloth bags in the packaging machine hopper to reduce dust diffusion during material filling.

II. Supporting Centralized Baghouse Dust Collection System

Dust extraction vents are installed at the material feeding point, mixer, and packaging station, and connected to a pulse-jet baghouse dust collector. Dust is extracted using negative pressure, and the collected dust is periodically mixed back into the raw materials for reuse. The filter bags are cleaned regularly to prevent clogging and dust collection failure. For humid environments, membrane-coated bags are used to prevent fertilizer from absorbing moisture and causing bag clogging.

III. Optimized Raw Material and Production Control

The moisture content of raw materials is strictly controlled upon entry into the warehouse, maintaining it at 4%–5%. Excessively dry particles easily generate floating dust; simple moisture retention can be achieved in the raw material storage area. Agglomerated materials are crushed and screened in advance; excessive fine powder is collected separately and mixed in small quantities to reduce the proportion of powder. To avoid excessively rapid feeding and sudden large-scale dust generation, variable frequency uniform feeding is adopted for stable material discharge.