A gyratory crusher is a high-performance primary crusher for reducing hard natural rock and large feed pieces. In the extraction of mineral resources, in rock quarrying, or in preparing material streams for further processing, it performs the first stage of size reduction. It is used less frequently in deconstruction and recycling processes, but can play a role in certain process chains, for example when pre-crushed, reinforcement-free concrete is further classified. A sensible combination arises when materials are pre-broken, separated, or low-stress split with concrete pulverizers or rock and concrete splitters from Darda GmbH and then further processed through suitable screening and crushing stages.
Definition: What is a gyratory crusher
A gyratory crusher is a continuously operating crushing machine with a conical crushing chamber. A centrally arranged, eccentrically driven spindle carries the moving mantle and generates a circular/oscillating motion against a stationary, concave liner. The feed material is captured in the narrowing crushing gap, compacted, and crushed by compression until it passes the set gap width. Gyratory crushers are used predominantly as primary crushers with very high throughput capacity. They are structurally different from cone crushers (cone), which are mainly used for secondary and tertiary stages.
Operating principle and design of the gyratory crusher
The crushing principle is based on compressive loading in the annular crushing chamber. The eccentric bearing arrangement creates uniform material stress and high capacity. Crucial is the constant material column at the inlet, which prevents bridging and keeps energy input stable.
Main components
- Spindle and eccentric: Carry the moving mantle and generate the circular motion.
- Fixed concave and moving mantle: Wear parts that shape the crushing chamber.
- Feed hopper and feed chute: For continuous, uniform feeding.
- Hydraulic gap adjustment: For controlling the gap width (Closed Side Setting) and providing tramp/overload protection.
- Lubrication and cooling: For bearings and the eccentric assembly.
- Discharge and outlet area: Handover to a conveyor belt or screening plant.
Operating principle
- Feeding from above into the conical crushing chamber.
- Compaction and size reduction in the narrowing gap by compression with shear components.
- Discharge of the crushed material once the set gap is reached; continuous throughput.
Note on differentiation: Cone crushers operate similarly but are usually smaller, have different motion characteristics, and are typically used in downstream crushing stages.
Fields of application of the gyratory crusher in the context of deconstruction, rock quarrying, and natural stone extraction
In natural stone plants and open-pit operations, the gyratory crusher is a classic primary crusher for very large and abrasive rocks. In rock quarrying and tunneling, it enables the processing of blasted or split blocks into conveyor-suitable sizes. In concrete demolition and special deconstruction, it is used less frequently directly because reinforcement is unfavorable. Synergies arise where Darda GmbH pre-processes the materials:
- Concrete pulverizers separate steel and concrete, reduce components, and create rebar-free pieces that are then further processed in stationary or mobile crushing circuits.
- Rock and concrete splitters create controlled lines of weakness, reduce vibrations, and allow larger block sizes for feeding primary crushers—even in sensitive areas or for special application.
In natural stone extraction, pre-splitting of bed edges improves block geometry, reduces oversize, and facilitates continuous feeding of the gyratory crusher. In strip-out and cutting, the gyratory crusher is not the focus; separating tools dominate there. Nevertheless, downstream crushing stages benefit from cleanly separated, de-metallized feed pieces.
Process chains: From opening to target grading
The efficiency of a circuit depends on the coordination of the components. Typical sequences:
Primary circuit in natural stone extraction
- Rock loosening by blasting or rock splitting cylinders from Darda GmbH (low-vibration, controlled fracture guidance).
- Loading coarse blocks into the primary crusher (gyratory crusher).
- Discharge onto a coarse screen; removal of fines to increase efficiency.
- Transfer to secondary crushers (e.g., cone crushers) and screening machines.
Concrete recycling in deconstruction
- Pre-selection, strip-out, and cutting of beams; use of concrete pulverizers to expose reinforcement.
- Pre-splitting of massive components with rock and concrete splitters to reduce vibrations.
- Feeding into suitable crushing stages (often jaw or impact crushers); gyratory crushers are only sensible for rebar-free material and large piece sizes.
- Screening, metal separation, quality assurance of recycled aggregates.
Selection criteria for using a gyratory crusher
- Feed piece size and geometry: Very large blocks and high hardness favor the gyratory crusher.
- Rock properties: Abrasiveness (e.g., quartz content), bulk density, moisture, and silt/clay fractions.
- Throughput requirements: Continuous feeding allows high tons per hour.
- Target grading and reduction ratio: Align Closed Side Setting (CSS) with downstream screening.
- Feeding: Hopper, apron feeder, vibrating feeder, pre-screening to relieve fines.
- Freedom from metal: Avoid reinforcement; prior separation using concrete pulverizers is advisable.
- Energy demand: Check power demand and grid/genset capacity; consistent material flow to increase efficiency.
- Mobility: Stationary, semi-mobile, or mobile—depending on deposit and logistics.
Operation, maintenance, and wear management
Regular care of wear parts and controlled feeding extend service life and ensure product quality.
Essential measures
- Gap control: Document CSS; adjust to target grading and wear condition.
- Wear parts: Replace mantle and concave in time; select surface profile to suit the material.
- Lubrication/cooling: Monitor oil quality, temperature, and flow.
- Overload protection: Hydraulic relief for tramp metal; safe clearing of blockages.
- Feeding discipline: Uniform feeding; avoid bridging; sort out or pre-crush oversize.
Particle shape, reduction ratio, and screening circuits
Particle shape (cubicity) and the distribution across the size band influence load-bearing capacity and mix properties. The gyratory crusher produces a robust primary crushed product at large reduction ratios. For tight size bands, the secondary/tertiary crushing with downstream screening usually takes over.
Practical control variables
- Closed Side Setting: Primary lever for target grading; tighter gaps increase fines.
- Pre-screening: Remove fines in advance to avoid overloading.
- Circulating load (recirculation): Common only in downstream stages; the gyratory crusher preferably operates in single-pass.
Alternatives and complements in deconstruction
In urban deconstruction projects, separating and pulling methods dominate, reducing components selectively and limiting emissions.
- Concrete pulverizers: Selective separation of concrete and reinforcement; ideal for preparing rebar-free fractions for downstream crushing stages.
- Rock and concrete splitters: Create fracture planes in massive components or rock; minimize vibrations and dust.
- Combi shears, multi cutters, steel shears: For sections, beams, and mixed structures; create metal-free feed materials.
- Tank cutters: Specific cutting tasks on hollow bodies; preparation for safe dismantling.
The gyratory crusher complements these methods wherever large, metal-free pieces are to be efficiently pre-crushed, for example at central processing sites.
Safety and environmental aspects
Safe operation, emission reduction, and the protection of adjacent areas are essential requirements. In general:
- Dust minimization: Enclosures, water spray at inlet and discharge, controlled material moisture.
- Noise reduction: Acoustic shielding and optimized drop heights.
- Vibrations: In deconstruction, prefer splitting and shear methods; in extraction, careful blasting/splitting planning.
- Safe maintenance: Shutdown, interlocks, secured access points, lifting gear for mantle changes.
- General requirements: Observe applicable regulations and recognized engineering rules; obtain project-specific permits.
Process variants from practice
Quarry with primary gyratory crusher
- Bench extraction and controlled splitting for block definition.
- Continuous feeding via hopper and dosing; coarse screening relieves the crusher.
- Downstream secondary/tertiary stages for defined size classes.
Inner-city concrete deconstruction
- Strip-out and selective deconstruction with concrete pulverizers; separation of reinforcement.
- Pre-splitting of massive foundations using rock and concrete splitters to reduce emissions.
- Further processing in suitable crushing circuits outside sensitive zones; gyratory crusher only for matching fractions.
Tunnel advance and shaft construction
- Rock loosening by blasting or splitting techniques to limit vibrations.
- Mobile/semi-mobile primary crushing stage; depending on logistics, a gyratory crusher as the primary stage.
- Screening and downstream crushing to produce defined backfill or base layers.
Typical misinterpretations and distinctions
- Gyratory crusher vs. cone crusher: The former is designed primarily for large feed pieces and very high throughputs; the latter usually works in secondary/tertiary stages with tighter settings.
- Reinforced concrete: Gyratory crushers are unsuitable; separate metal-bearing materials beforehand with concrete pulverizers.
- Oversize dominance: Highly non-uniform blocks without pre-splitting overload the crusher; rock and concrete splitters create processable geometries.
Planning, logistics, and energy efficiency
A well-planned process chain reduces downtime and energy consumption. Important levers:
- Material flow: Uniform feeding, sufficient buffers, coordinated conveying technology.
- Selective pre-reduction: Splitting and shears reduce metal content and create crushable pieces.
- Energy: Avoid load peaks, link speed/gap to material flow, pre-screen fines.
- Quality: Ongoing size-band control, adapt screen decks, feedback loops between crushing stages.