The Core Value of the Mixing Process in an Organic Fertilizer Production Line

The mixing process is like the “heart” of the entire organic fertilizer production line, fulfilling the crucial mission of homogenizing raw materials and promoting composting. This directly determines the nutrient balance and application safety of the final product. This seemingly simple “mixing” step actually embodies rigorous process standards and technical considerations.

From a process perspective, the mixing process must address two key issues: precise raw material ratios and uniform moisture distribution and microbial environment. Organic fertilizer raw materials come from a complex source, with significant variations in nutrient content and physical properties among materials like livestock and poultry manure, straw, and mushroom residue. Inhomogeneous mixing can lead to localized enrichment or depletion of core nutrients like nitrogen, phosphorus, and potassium in the finished product, seriously impacting fertilization effectiveness. Furthermore, the moisture content must be controlled within the optimal composting range of 50%-60% during the mixing process. Continuous stirring breaks up material clumps, creates a sufficient oxygen environment for aerobic microorganisms, accelerates the decomposition and conversion of organic matter, and prevents the localized anaerobic production of harmful gases such as hydrogen sulfide.

The current mainstream mixing equipment is primarily a double axis mixer, which uses counter-rotating blades to create a strong convection mixing field. Combined with an adjustable-speed agitator shaft, the mixing intensity can be flexibly adjusted based on the raw material’s moisture content and particle size. High-quality equipment also features a water sprayer and temperature sensor to monitor material temperature changes in real time during mixing. When the temperature rises above 55°C, indicating peak microbial activity, the agitator speed should be appropriately reduced to avoid excessive energy consumption. If the temperature is abnormally low, the water supply system adjusts the humidity to ensure a stable composting process.

It is important to note that quality control of the mixing process must be implemented throughout the entire production process. Too short a mixing time can lead to insufficient homogeneity, while too long a mixing time can cause excessive fragmentation and damage the organic matter structure. Typically, the mixing time for each batch of material should be controlled between 8 and 12 minutes, and sampling testing should be performed to ensure that the uniformity error does not exceed 3%. Strict control of the mixing process in organic fertilizer production lines is not only fundamental to ensuring that organic fertilizer products meet national standards but also crucial for the resource utilization of agricultural waste and the promotion of green agriculture.

Analysis of Common Problems in the Organic Fertilizer Production Line

Organic fertilizer production lines improve efficiency through continuous operation, but improper integration of various stages can easily lead to problems, impacting production stability and product quality.

The raw material pretreatment stage is prone to conveyor blockage. If raw materials such as straw and manure are not crushed to a particle size of 5-10mm or have a moisture content exceeding 65%, they can easily form lumps in belt conveyors and screw feeders, causing production line downtime. Screener machines should be added to the pretreatment stage to control the particle size. At the same time, the moisture content should be adjusted to 55%-60% through drying or the addition of dry materials to ensure smooth material conveyance.

Uneven compost turning and insufficient oxygen supply are common problems in fermentation systems. If the chain compost turning machine rotates too fast or has an inappropriate stroke setting, the compost will not be turned thoroughly, resulting in local temperatures below 55°C and failure to achieve the desired compost maturity. Insufficient fan pressure can cause oxygen deprivation in the compost, producing harmful gases such as hydrogen sulfide. To address this, adjust the compost turner speed according to the pile height (2-3 rpm is recommended). Regularly check the fan filter to ensure a ventilation rate of 0.3-0.5 m³/min per cubic meter of pile.

The drying process is prone to moisture control imbalances. If the feed rate to the drum fertilizer dryer fluctuates, or if the hot air temperature fluctuates by more than ±5°C, the finished product moisture content will fluctuate (the acceptable standard is 15%-20%), impacting subsequent granulation. Install an automatic feed regulating valve to stabilize the feed rate, employ a temperature control system to precisely control the hot air temperature at 80-100°C, and install a moisture detector at the discharge end for real-time monitoring.

Inaccurate metering and loose sealing are common problems in the packaging process. Aging load cells in quantitative packaging machines can lead to bag weight errors exceeding ±2%. Low temperatures or insufficient pressure in heat sealers can cause cracking in the bag seals and moisture absorption and caking of the finished product. The load cell must be calibrated monthly, the heat sealing temperature must be adjusted to 150-180°C, and the pressure must be controlled at 0.3-0.5 MPa to ensure packaging quality.

Addressing issues in all aspects of the organic fertilizer production line requires strengthening equipment maintenance and process control to achieve continuous and stable production and guarantee the quality of organic fertilizer.