Harsintavaiheet

Harsintavaiheet are the sequential stages in a screening process used to separate material by particle size. In Finnish technical literature, the term describes the system of screens and work steps that classify bulk material into defined size fractions as part of mineral processing, aggregates production, and recycling operations.

The main purpose of harsintavaiheet is to create uniform size fractions for further processing or sale, remove oversized material, and improve downstream efficiency. They are typically implemented as a multi-stage arrangement, where feed passes through a coarse screen to reject large lumps, followed by intermediate screens to obtain mid-sized fractions, and a final screen to produce fines. In many operations, oversize material from one stage is conveyed back to crushers for reprocessing, forming a closed-loop classification circuit.

Common equipment includes vibrating screens, linear screens, grizzly screens, and trommels. Screens may operate wet or dry, and configurations vary from single-deck to multi-deck systems, with multiple decks providing several cut-points in one pass. Factors influencing performance include feed rate, particle size distribution, moisture content, screen aperture, deck inclination, vibration, and material properties such as hardness and shape.

Applications span mining and ore processing, construction and mineral aggregates production, and recycling of construction and demolition waste. Proper design and control of harsintavaiheet help optimize recovery, control product quality, reduce wear, and minimize energy use in the overall processing chain.