Laboratory Roll Crusher

What is the Laboratory Roll Crusher?

A laboratory roll crusher reduces crushed ore from about 10 to 20 mm to 1 to 3 mm between two rotating rolls, producing a narrower size distribution with fewer fines than impact crushers. It is a common second-stage machine.

Overview

Two hardened rolls rotate towards each other and draw material into the gap between them, where it is crushed by compression and shear. The roll gap sets the product size and is adjusted by screws or shims, and one roll is usually spring-loaded so that uncrushable objects pass without damaging the machine. Roll surface may be smooth, corrugated or toothed, depending on the material: toothed rolls grip sticky or coarse feed, while smooth rolls give a flatter product with fewer fines. Throughput is typically 50 to 500 kg per hour for laboratory sizes, with roll diameters of 150 to 300 mm. Roll crushers suit ores that fracture by compression and are less suitable for very hard, abrasive material, where roll wear becomes rapid and frequent adjustment is needed.

How does it work?

Size reduction in mineral laboratories relies on compression, impact and shear, and each machine type applies them differently. Jaw crushers compress rock between a fixed and a moving jaw, and the closed-side setting controls product size. Roll crushers pass material between two rotating rolls and give a narrower product with less fines. Cone crushers use a gyrating mantle inside a concave to crush continuously at higher throughput. Hammer crushers strike material with swinging hammers against a breaker plate and discharge it through a screen. Reduction ratio per stage is limited, typically three to six to one, so laboratories arrange two or three crushers in series: a primary jaw, a secondary roll or cone and a final pulverizing stage. Feed must be steady, dry and below the rated size, because overfeeding stalls the drive and raises wear. Grinding surfaces are made of manganese, chrome or tungsten carbide, and the choice affects contamination.

What are the key features?

• Two counter-rotating hardened rolls with adjustable gap
• Smooth, corrugated or toothed roll surface options
• Spring-loaded roll for protection against uncrushable objects
• Feed size up to about 20 mm
• Product of 1 to 3 mm with a narrow size spread
• Enclosed housing with extraction and collecting tray

What are the technical specifications?

A typical laboratory roll crusher configuration offers roll diameter of 150–300 mm, maximum feed size of 10–20 mm, product size of 1–3 mm adjustable, throughput of 50–500 kg/h, roll surface of Smooth, corrugated or toothed and roll material of Hardened alloy steel or tungsten carbide. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Laboratory Roll Crusher is used in second-stage crushing after a jaw crusher, preparation of brittle ore and slag samples, reduction of drill core to pulverizer feed size and industrial mineral sample preparation. Across the wider Sample Crushers class, laboratories also deploy it for primary crushing of mine and drill core samples, secondary crushing before pulverizing and concentrate and tailings sample preparation.

Which standards and certifications apply?

Relevant standards and methods include ISO 3082, ISO 12743, ASTM E877, GB/T 2007 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Install crushers on a rigid floor with enough clearance for the moving jaw or cone, and anchor them so vibration does not loosen the drive. Provide dust extraction designed for mineral dust and, where silica is present, follow local occupational exposure limits and provide respiratory protection. Feed in small increments at the rated rate rather than in batches that choke the chamber, and never feed wet, sticky material that blinds screens. Record the closed-side setting and product size after each adjustment, and replace worn plates, rolls or hammers before the product size drifts outside specification. Reduce dust formation by keeping material slightly damp only if the method allows, since added water changes the sample moisture. Clean thoroughly between samples, and run a small quantity of the next sample through as a purge when trace-grade work is done.

How do I select the right Laboratory Roll Crusher?

Choose the roll crusher for the second stage when a narrow product size and low fines content matter, and when the ore fractures by compression. Specify roll diameter, surface type and gap range, and expect to replace or resurface rolls after processing hard abrasive material.

How does it compare with other Sample Crushers variants?

Work backwards from the analytical fineness you need. Match the primary crusher feed opening to the largest lump arriving from the field, then choose one or two further crushing stages so that the pulverizer receives material below its rated feed size, usually 1 to 3 mm. Check the reduction ratio at each step and keep it moderate, since forcing a large reduction increases wear and produces a wider size spread. Consider hardness and abrasiveness: quartz-rich and iron ore samples wear manganese steel quickly, so hardened or carbide-lined surfaces may be justified. Decide how contamination-sensitive the assay is, because chromium and iron from the crushing surfaces bias Ni, Cr and Fe values. Look for sealed, dust-extracted housings since respirable crystalline silica is a health hazard, and for adjustable settings with an accessible calibration, so the product size can be verified on a sieve.