I. Role of the Artificial Bed Layer
In the sub-screen discharge method, the primary functions of the artificial bed layer are:
Controlling the Discharge Rate of Heavy Minerals: The pore structure formed by the bedding stones affects the settling and discharge of heavy minerals.
Improving Separation Precision: A properly configured bed layer reduces the mixing of light minerals, thereby enhancing the grade of the concentrate.
II. Selection Criteria for Bedding Stones
1. Appropriate Particle Size
The particle size of the bedding stones should be 3–6 times the maximum particle size of the feed ore. Additionally, the stones should be 1.2–2 times larger than the screen aperture to prevent loss.
2. Selection of Specific Gravity
The specific gravity of the bedding stones should be close to or slightly less than that of the heavy minerals (e.g., magnetite). This ensures the stones remain at the bottom layer while allowing heavy mineral particles to pass through smoothly. Common materials for bedding stones include magnetite and hematite.
3. Particle Shape
Rounded particles are preferred to minimize edges and corners, reducing bed layer resistance and improving mineral flow. Avoid flaky or needle-shaped particles to prevent clogging of the bed layer pores.
III. Adjusting the Thickness of the Artificial Bed Layer
The thickness of the bed layer directly affects the yield and grade of the concentrate. Adjustments should be made based on actual separation results:
Observe Concentrate Quality: If the discharge of heavy minerals is too slow, increase the particle size of the bedding stones or reduce the bed layer thickness.
Check Sub-screen Discharge: If excessive light minerals are mixed in, increase the bed layer thickness or use bedding stones with a higher specific gravity.
Regularly Clean the Screen Mesh: Prevent wear or clogging of the bedding stones, which could impact separation efficiency.
The bed layer of a sawtooth wave jig should be dynamically adjusted according to ore characteristics and separation performance to achieve optimal processing indicators.