I. Primary Crushing Equipment: Jaw Crusher
The jaw crusher serves as the core equipment in the primary crushing stage of marble processing, designed to handle raw marble materials with a diameter not exceeding 1.2 meters. Operating on the principle of compression crushing, it applies pressure to materials through the reciprocating motion of the moving and fixed jaws, achieving highly efficient crushing. Its key design feature is the V-shaped deep cavity structure, which significantly increases material throughput by prolonging the residence time within the crushing chamber. According to actual production data, jaw crushers equipped with V-shaped deep cavities achieve a 15%-20% increase in hourly throughput compared to traditional models. They also deliver a crushing ratio (ratio of feed size to discharge size) of 5-8, effectively meeting the feed requirements for subsequent medium and fine crushing stages.
II. Medium and Fine Crushing Equipment: Cone Crushers and Impact Crushers
Cone Crusher
Operating on the principle of laminar crushing, this equipment subjects materials to repeated compression, bending, and shearing within the crushing chamber. The resulting products predominantly exhibit a cubic structure, with needle and flake-shaped particles controllable below 10%. Its discharge opening adjusts hydraulically from 3 to 60 millimeters, enabling stepless adjustment to accommodate varying particle size requirements. For instance, when producing construction sand, the discharge opening can be set to 10-20 mm to yield uniformly sized intermediate products. For fine aggregate production, it can be reduced to 3-5 mm.
Impact Crusher
Suitable for medium and fine crushing operations, this machine employs high-speed rotating impact plates to strike materials, causing them to fracture along natural fissures. Its discharge particle size can be precisely controlled by adjusting the gap between the impact plate and the hammer plate, with a minimum adjustable size below 50 mm. This equipment is particularly suitable for processing materials with high moisture content, such as marble quarried during the rainy season. Its crushing efficiency is approximately 12% higher than that of cone crushers, while reducing equipment wear by 8%.
III. Sand-Making Equipment: Impact Sand Maker
The impact sand maker integrates fine crushing and shaping functions. Using either “stone-on-stone” or “stone-on-iron” crushing methods, it refines materials to 0-5 mm. The produced sand features well-rounded grains with a rational particle size distribution, meeting the GB/T 14684-2011 “Sand for Construction” standard. In actual production, this equipment achieves sand-making efficiency of 50-80 tons per hour, with the fineness modulus of sand stably controlled between 2.6 and 3.0 to meet the requirements of different concrete strengths. For instance, producing C60 and higher-strength concrete necessitates Class I sand with a fineness modulus of 2.8-3.0. The impact sand maker enables precise control by adjusting feed particle size and rotational speed.
IV. Supporting Auxiliary Equipment: Grading, Washing, and Grinding
Vibrating Screen
Featuring a multi-layer screen design, it simultaneously grades coarse, medium, and fine sand. For instance, a three-layer vibrating screen (with mesh apertures of 5mm, 2.5mm, and 1.2mm) achieves precise sand particle grading with an efficiency exceeding 95%.
Sand Washer and Fine Sand Recovery Machine
The sand washer removes mud and silt from sand particles through water flushing, while the fine sand recovery machine utilizes a cyclone to recover lost fine sand (particle size 0.075-0.6mm). Together, they reduce the mud content in sand to below 0.5%, significantly improving sand quality. Calculations indicate that using this combination of equipment can increase the market price of sand by 10%-15%.
Grinding Equipment
This equipment processes marble into powder ranging from 80 to 2500 mesh, meeting demands across chemical, coating, and paper industries. For instance, 200-mesh marble powder can be used in stone-effect coatings at a 60%-70% addition rate. Ultra-fine powder exceeding 800 mesh serves as filler for plastics and rubber, enhancing product strength and abrasion resistance.
Primary Applications of Machine-Made Sand in Marble
I. Construction Industry Applications
As Construction Aggregate
Machine-made sand features uniform particle size (continuous gradation) and excellent wear resistance, making it widely used in highways, railways, municipal construction, and other fields. For instance, in the base layer of expressway pavements, a 3:7 mixture of machine-made sand and crushed stone significantly enhances the pavement's resistance to rutting.
Classification and Application Scenarios
Class I Sand (Fineness Modulus 3.0-3.7): Suitable for high-strength concrete C60 and above, such as pile foundations for high-rise buildings and bridge main girders;
Class II Sand (Fineness Modulus 2.3-3.0): Suitable for concrete C30-C60, such as ordinary residential buildings and municipal roads;
Class III Sand (fineness modulus 1.6–2.2): Suitable for concrete and mortar below C30, such as walls and flooring.
II. Industrial Applications
Stone-Effect Coating Filler
When used as a filler at 60–70% by volume, manufactured sand enhances coating weather resistance and realism. For instance, a certain brand of stone-effect coating extended its service life from 5 to 8 years after incorporating manufactured sand, while achieving more realistic stone textures.
Artificial Granite Raw Material
Mixing manufactured sand with resin at a 3:1 ratio and curing under high temperature and pressure produces artificial granite with strengths exceeding 80 MPa. This material is widely used in interior decoration, countertops, and similar applications.
III. Environmental Protection and Resource Recycling
Utilizing tailings for sand production reduces solid waste accumulation and environmental pollution. Statistics indicate that processing 10,000 tons of tailings can save approximately 10 square meters of land while producing about 8,000 tons of manufactured sand. With current market prices ranging from 40 to 102 yuan per ton, the economic benefits are significant. For instance, a company processing 500,000 tons of tailings annually achieves a profit of 20 million yuan.
Production Process Example
Taking a marble processing plant as an example, its production flow is as follows:
Coarse Crushing: Waste material is crushed by a jaw crusher to ≤300mm;
Medium Crushing: Further crushed by a cone crusher to ≤60mm;
Fine Crushing: Finely crushed by an impact sand maker to 0-5mm;
Classification: Vibrating screens separate material into coarse sand (2.5-5mm), medium sand (1.25-2.5mm), and fine sand (0.63-1.25mm);
Finished Product: Washed sand meets specifications after processing through a sand washer.
This process achieves over 90% raw material utilization and reduces energy consumption per unit product by 15% compared to traditional methods.
