How to set up a two-stage crushing circuit for quartz stone processing

Quartz rock has a Mohs hardness of 7 and strong abrasiveness. A well-designed two-stage crushing circuit reduces run-of-mine quartz down to the correct feed size for subsequent rod mill / ball mill or VRM grinding, while minimizing liner and media wear. This article describes the standard flow, equipment selection, parameter settings, closed-circuit configuration and key operational tips for quartz processing, tailored for quartz-mill.com.

1. Purpose of Two-Stage Quartz Crushing

Two-stage crushing reduces large raw quartz lumps to 10–25 mm, which is the ideal feed size for rod mills. For ball mill feeding, the target product after two-stage crushing can be further tuned to 2–10 mm.

• Primary crushing: reduce big run-of-mine rock to 50–100 mm
• Secondary crushing: reduce 50–100 mm material down to 10–25 mm
  The circuit can be open or closed. Closed circuit with vibrating screen is strongly recommended for quartz.

2. Complete Process Flow

Run-of-mine quartz → Grizzly feeder → Jaw crusher (1st stage) → Vibrating screen → Cone crusher (2nd stage) → Final product stockpile
Closed-circuit version: Oversize from screen returns back to cone crusher for re-crushing.

Equipment breakdown

1. Grizzly vibrating feeder
   Removes fine soil and small gravel before jaw crusher, improves jaw crusher efficiency and reduces wear.
2. Jaw crusher (Primary crushing)
   For coarse breaking of large quartz boulders. Choose heavy-duty jaw crusher with manganese steel liners.
   • Feed size: up to 300–800 mm (depends on jaw model)
   • Discharge setting: 50–100 mm
3. Vibrating screen
   Double-deck inclined vibrating screen, installed after jaw crusher or after cone crusher for closed circuit.
   • Separate qualified material and oversize lumps.
4. Cone crusher (Secondary crushing)
   For medium crushing of hard abrasive quartz. Standard or medium cone crusher (not short head fine cone) for two-stage crushing. Short-head cone is used for tertiary fine crushing.
   • Feed to cone: 50–100 mm
   • Closed-circuit discharge target: 10–25 mm
5. Belt conveyors for material transfer
6. Magnetic separator (optional but recommended)
   Install before the grinding mill to remove tramp iron from crushed quartz, protecting downstream grinding equipment.

3. Open Circuit vs Closed Circuit for Two-Stage Crushing

Open circuit two-stage crushing

Jaw → Cone, no return screen.

• Pros: Lower investment, simpler layout, fewer conveyors.
• Cons: Wide particle size distribution, contains many oversized particles. Not suitable for quartz grinding lines, because oversize feed will cause rod tangling or accelerated mill wear.
• Application: Only for small simple plants with low requirements.

Closed circuit two-stage crushing (Recommended for quartz)

Jaw crusher → Cone crusher → Vibrating screen → Oversize returns to cone crusher.

• Pros: Stable top size, controlled PSD, consistent feed for grinding mill.
• Cons: Extra vibrating screen and return conveyor, slightly higher capital cost.
• Circulating load: 30–80% for quartz two-stage closed crushing.

4. Key Parameter Settings

Jaw crusher (Primary)

• CSS (closed side setting): 50–100 mm
• Product: 50–100 mm
• Check liner wear regularly; quartz abrades jaw plates quickly.

Cone crusher (Secondary medium cone)

• CSS: 10–25 mm, adjust CSS according to target product size.
• Do not run too small CSS; it will increase liner wear and reduce throughput.
• Choke feed operation is preferred for cone crusher, to achieve laminated crushing and better particle shape.

Vibrating screen

• Screen aperture: set upper screen to separate oversize above 25 mm.
• Screen mesh material: high wear-resistant steel or polyurethane screen panels for abrasive quartz.
• Keep screen deck clean to prevent blinding.

5. Equipment Selection Rules for Hard Quartz

1. Primary crusher: Jaw crusher only. Do not use impactor for primary quartz crushing. Impact blow bars wear extremely fast with hard quartz.
2. Secondary crusher: Cone crusher is the standard choice. HSI impact crusher is not recommended for hard quartz secondary crushing due to very high wear cost. VSI can be added later as shaping stage, not for two-stage crushing.
3. Wear parts: use high manganese or high chromium alloy liners to extend service life.

6. Critical Operational Best Practices

1. Remove clay and fine dirt ahead of crushing by grizzly feeder. Clay will block screen and reduce crushing efficiency.
2. Maintain choke feeding for cone crusher. Consistent feed helps laminated crushing and reduces liner wear.
3. Regularly inspect liner wear. Worn liners increase product top size.
4. Control tramp iron. Metal entering cone crusher will cause severe damage. Metal detector + magnetic separator is suggested.
5. Avoid feeding wet sticky quartz, which causes screen blinding.

7. Typical Application Matching

• Two-stage closed circuit (Jaw + Cone + screen return): produce 10–25 mm feed for rod mill to make 20–80 mesh quartz sand.
• If you need finer product (2–10 mm) for ball mill feeding: add a third short-head cone stage (three-stage crushing).

Comparison Table

A standard two-stage crushing circuit for quartz stone is jaw crusher for primary crushing + medium cone crusher for secondary crushing, equipped with vibrating screen in closed circuit. It reduces raw quartz rock to stable 10–25 mm feed size for rod mill. For hard abrasive quartz, cone crusher is the best secondary crusher instead of impact crusher, to minimize wear cost and maintain stable particle size.