1. Project Background and Challenges:
This section outlines the characteristics of Tajikistan’s abundant river pebble resources—specifically their high hardness and strong abrasiveness—which impose extremely rigorous demands on equipment durability and stability.
2. Detailed Process Flow:
The project employs a distinct "three-stage, one-closed-circuit" process flow, supplemented by shaping and material recirculation stages. It describes, phase by phase, the complete journey of materials from initial feeding to the output of finished products of various specifications.
• Phase 1 (Coarse Crushing): Utilizes a C-series jaw crusher to reduce raw materials (sized ≤500mm) to a size of ≤120mm.
• Phase 2 (Closed-Circuit Intermediate Crushing): Employs a Symons cone crusher (Standard Type) integrated with a vibrating screen to form a closed-circuit loop, ensuring that the material entering the fine crushing stage possesses a uniform particle size (≤40mm).
• Phase 3 (Fine Crushing and Screening): Utilizes a Symons cone crusher (Short-Head Type) for fine crushing, followed by precise classification using two vibrating screens. This stage produces aggregates in the 10–20mm and 5–10mm size ranges, while routing the 0–5mm material to the sand-making stage.
• Phase 4 (Sand Making and Shaping): Employs a Vertical Shaft Impact (VSI) crusherto shape the 0–5mm material, thereby improving particle shape, producing high-quality manufactured sand, and allowing for the adjustment of the fineness modulus.
Core Equipment Lineup:
| Equipment Name |
Model |
Quantity |
Functional Positioning |
| Jaw Crusher |
C Series (Heavy-duty) |
1 unit |
Primary crusher, wide feed opening |
| Symons Cone Crusher |
Standard/Short-head type |
2 units |
Mainstay for medium and fine crushing, layered crushing |
| Sand Making Machine |
Vertical Shaft Impact Crusher |
1 unit |
Particle shape shaping, producing 0-5mm manufactured sand
|
| Circular Vibrating Screen |
High-efficiency Heavy-duty |
2 units |
Multi-layer grading, screening efficiency >90% |
| Belt Conveyor |
B1000/B800 |
Several |
Fully sealed idlers, low-energy conveying |
Three-Stage Closed-Circuit + Shaping and Recycled Material Process Flowchart
Stage 1: Coarse Crushing – Jaw Crusher Opens the Way, Large Pieces Subdue
• Raw Material: 50-500mm river pebbles, evenly fed by a vibrating feeder
• Equipment: C-Series Jaw Crusher
• Discharge Particle Size: ≤120mm
Note: The C-Series jaw crusher adopts deep-cavity crushing and a large eccentricity design, resulting in strong single-machine processing capacity. River pebbles are crushed to below 120mm in a single pass, paving the way for efficient operation of the subsequent cone crusher.
Section 2: Closed-Circuit Crushing & Screening – Main Zone of Cone Crusher
Equipment 1: Simons Cone Crusher (Standard Type)
• Feed Size: ≤120mm
• Discharge Size: ≤40mm
Operating Instructions:
• Coarse crushed material is conveyed to Vibrating Screen #1 via belt conveyor;
• Oversize material (>40mm) is returned to the Simons Cone Crusher (Standard Type) for further crushing;
• Undersize material (≤40mm) enters the next stage buffer bin.
This section forms the first closed-circuit cycle, ensuring uniform particle size of the material entering the fine crushing section and significantly reducing the load on the fine crushing cone crusher.
Section 3: Fine Crushing & Main Screen Classification – Finished Product Separation
Equipment 2: Simons Cone Crusher (Short-Head Type)
• Feed Size: ≤40mm
• Discharge Size: ≤25mm
Operating Instructions:
• Undersize material from the medium crushing screen enters the short-head cone crusher for fine crushing;
• The crushed material is fed into two vibrating screens (parallel/series configuration) for precision classification;
Screen Configuration: 20mm / 10mm / 5mm three-layer mesh.
Detailed Classification Path of Two Vibrating Screens:
① Above 20mm → Return to short-head cone crusher (closed-loop circulation)
② 10-20mm → Finished product stockpile (coarse aggregate)
③ 5-10mm → Finished product stockpile (fine aggregate)
④ 0-5mm → Enter the sand making machine shaping area
Section 4: Sand Making and Shaping – Particle Shape Optimization, High-Quality Manufactured Sand
Equipment: Vertical Shaft Impact Sand Making Machine
Feed: 0-5mm undersize fine material
Work Objectives:
• Improve the particle morphology of 0-5mm material, remove sharp edges, and improve roundness;
• Adjust the fineness modulus (controlled between 2.4-3.0, adjustable);
• Produce an additional portion of ultrafine powder (depending on market demand).
Finished Product Destination: After being sorted or screened by a small sieve, the 0-5mm high-quality manufactured sand from the sand making machine is stored separately.
