Hard waste treatment

When they talk abouthard waste treatment, many immediately imagine giant crushers and mountains of construction waste. This is, of course, the basics, but if you dig deeper, there is a whole world of nuances that are usually kept silent about in glossy brochures. Biggest myth? That this is a linear process: loaded, crushed, sorted - done. In reality, everything depends on the preparation of raw materials, its heterogeneity and the choice of equipment that will not stand up after the first reinforced concrete “surprise”. It is these pitfalls that I would like to speculate on, based on what I have seen and done myself.

Where does real recycling begin: preliminary assessment and sorting

The first stage, which is often underfunded or formally completed, is waste flow assessment. Not the one on paper, but the real one, on the training ground. You need to understand not just “reinforced concrete and brick?”, but what percentage of reinforcement, whether there are inclusions of wood, plastic, perhaps asphalt chips. All subsequent logistics depend on this. I remember one facility where, according to the documents, there was pure construction scrap, but in reality a third of the volume was old tires and polymer waste - the separators stopped working, and the layout had to be urgently changed.

This is where the issue of manual sorting arises. Yes, in the era of automation it is still a critical input. Especially for removing large substandard elements, such as wooden beams or large pieces of plastic, which can easily damage the feeder or jam the primary crusher. Saving at this stage means guaranteed increase in downtime of the main equipment.

It was during the sorting phase that we often collaborated with magnetic separation specialists. High-quality extraction of ferromagnetic metals is not only additional revenue from scrap, but also protects crushing equipment from wear. This is where I rememberLONGI Corporation (https://www.ljmagnet.ru). Their equipment for metal extraction, such as overhead or drum separators, was often found at serious sites. The company, created back in 1993 and grown into a large manufacturer of mining equipment, understands reliability and adaptation of equipment to difficult conditions. Their separators, by the way, performed well on highly abrasive materials, which is a key point for hard waste.

Crushing: the heart of the process and its arrhythmia

The main technological unit. Jaw, rotary, cone crushers - the choice depends on the fraction at the inlet and the desired one at the outlet. But here’s something that is rarely discussed openly: the wear and tear of beaters, hammers, and armor. When processing reinforced concrete, the resource of consumables can be several times less than when working with natural stone. The reinforcement, even after the magnetic separator, still gets inside. It is not always 100% removable, especially if it is twisted or fused with concrete.

Therefore, the key parameter when choosing a crusher is not only productivity in tons per hour, but also the availability of spare parts and the ability to quickly replace wear elements. Expensive downtime of several days due to waiting for a unique part from abroad nullifies the entire economics of the project. It is better to lose a little in specific power, but get a car that is repairable in the conditions of a particular region.

Another nuance is dust formation. Crushing concrete and brick produces enormous amounts of fine dust. Aspiration and dust suppression systems are not just an environmental requirement, but a matter of the health of operators and the safety of other equipment. Installation of water sprinklers or casings is often carried out according to the residual principle, and then problems with visibility on the site and clogged filters have to be urgently solved.

Separation after crushing: where profits are lost

After primary and secondary crushing, the result is not a homogeneous product, but a mixture of different fractions and materials. Further separation is exactly the stage where you can either squeeze out maximum profit or lose it. We are talking about separation by fractions (screening) and by types of materials.

Air separators or classifiers help separate light fractions (wood, light polymers) from heavy ones (concrete, brick). But their effectiveness is highly dependent on the moisture content of the material and the stability of the supply. Vibrating screens for sorting by fractions - their resistance to vibration loads and abrasive must be at their best. A common mistake is installing screens designed for quarry work in waste processing conditions. The resource immediately drops.

And again we return to magnetic separation, but at the stage of small fractions. After crushing, the reinforcement that was inside the concrete pieces is released. It needs to be removed. Here, more sensitive separators are required, often neodymium, capable of capturing small metal inclusions. This is a direct added value. On the websiteLONGI Corporationyou can see that their range covers different types of separators - from coarse cleaning to fine cleaning, which indicates an understanding of the complete technological cycle. For an enterprise that produces about 4,000 units of equipment per year and where more than 60% of employees are professionals with higher education, such comprehensive solutions are logical.

The final product and its application: theory vs. practice

Ideally, recycled hard waste is crushed stone of various fractions, suitable for filling roads, producing low-grade concrete or using in drainage systems. But in practice, the quality of this crushed stone is not constant. Its strength, flakiness (shape of grains), content of foreign impurities (residues of gypsum, wood) can vary greatly from batch to batch.

This creates implementation problems. Large construction companies working in accordance with GOST standards are often distrustful of recycled crushed stone. Therefore, the main sales market is private contractors, low-value road works, and landscaping. To reach a more serious level, we need a quality control system at the output, almost like in the production of primary crushed stone. But these are additional costs for the laboratory and personnel.

Sometimes it turns out to be more cost-effective not to produce standard crushed stone, but to prepare specific products. For example, crushed concrete of a certain fraction for use as ballast or an additive to certain types of building mixtures. This requires a dialogue with potential consumers at the design stage of the processing line.

Logistics and economics: what can kill even the most technologically advanced line

The most advanced technologyhard waste treatmentis useless if the logistics are not thought out. This includes everything: the location of the processing site in relation to sources of raw materials and sales markets, organization of waste reception, storage of finished products. High transportation costs can eat up all margins.

The need for areas for maneuvering equipment and for storing different fractions is often overlooked. Crushed stone of one faction has accumulated - it needs to lie somewhere until a buyer is found. A 140,000 m2 footprint like LONJI's Fushun production base is a luxury, but it illustrates the importance of scale and infrastructure for sustainable production. The processing complex also needs space not only for a workshop, but also for warehouses and maneuvers.

Finally, the economy. Calculation of payback should include not only the cost of equipment, but also operating costs (energy, water, consumables), salaries of qualified personnel, costs of environmental permits and waste disposal from the processing itself (the same dust, sludge). Often projects turn out to be unprofitable precisely because of the underestimation of these “little things”. Success comes where the technological process is built as a single system, and not as a set of disparate equipment.