For the processing of reinforced concrete products, mobile rotary crushers with a gap of ≥12 mm, a magnetic separator of ≥800 Gauss and a weight of 35–55 tonnes are selected; these are capable of recovering up to 98% of reinforcement.
Mobile rotary crushers with a gap between the rotor and the deflector plates of at least 12 millimetres, in accordance with the manufacturers’ official specifications, are ideally suited for processing reinforced concrete products.
According to the results of field trials involving 12 crusher models from various manufacturers, the presence of a built-in magnetic separator with a magnetic field strength of at least 800 Gauss enables up to 98 per cent of steel reinforcement to be recovered from the final crushed material without the need for additional manual operations. Furthermore, the design of the crushing chamber housing, featuring reinforced manganese steel liners, demonstrates a 32 per cent reduction in the wear rate of working surfaces compared with standard solutions, according to production test data.
For most reinforced concrete recycling tasks, a particle size range of 0 to 40 millimetres is required, whilst, according to engineering guidelines, adjusting the position of the deflector plates allows for a particle size distribution with a proportion of particles smaller than 5 millimetres ranging from 15 to 45 per cent, depending on the initial density of the feed material. When processing reinforced concrete with reinforcement up to 16 millimetres thick, in accordance with official specifications, no jamming of the crushing chamber occurs provided the recommended feed rate is observed.
According to measurements taken at construction sites, the total weight of mobile rotary crushers suitable for processing reinforced concrete products ranges from 35 to 55 tonnes according to official technical specifications, which allows them to be transported between sites on standard low-loader trailers without the need for additional permits for the carriage of oversized loads in most regions. Furthermore, a turning circle of 12 metres, as per design data, allows for manoeuvring on confined building demolition sites without the need for additional support equipment.
Equipment type: Mobile rotary crusher; minimum clearance between the rotor and the deflector plates: 12 mm (official specifications); magnetic separator strength: not less than 800 Gauss (field test results), Maximum rebar thickness in the feed material: up to 16 mm (official specifications); Equipment weight: 35–55 tonnes (technical data sheets); Output particle size adjustment range: 0–40 mm (engineering reference range); Reinforcement recovery rate up to 98 per cent (field tests).
Is it possible to process reinforced concrete with reinforcement bars thicker than 16 millimetres using a standard rotary crusher? Test results show that where the rebar is thicker than 16 millimetres, there is an increased risk of the crushing chamber jamming and accelerated wear of the working parts; it is therefore recommended that the rebar be cut to the specified size beforehand. Is it necessary to further clean the crushed material to remove any remaining reinforcing bars? If a built-in magnetic separator with a field strength of at least 800 Gauss is fitted, no additional manual or mechanical cleaning is required, according to production test data. How often do the crushing chamber liners need to be replaced when processing reinforced concrete continuously? According to the engineering reference range, provided the recommended operating conditions are observed, the liners need to be replaced after between 800 and 1,200 operating hours, depending on the density of the raw material being processed.
