Ultrafine particles

Ultrafine particles (also known as fine dusts) are solid particles with a diameter of less than 10 micrometres (µm). In particular, nanofine particles with diameters of less than 100 nanometres (nm) are becoming increasingly important in process engineering, industry and medicine. Despite their wide range of applications, they pose a serious challenge to health, the environment and plant engineering due to their dust pollution.

Properties and classification of ultrafine particles

Ultrafine particles can be classified according to their origin and composition:

• Organic dusts (e.g. milk derivatives, active pharmaceutical ingredients)
• Inorganic dusts (e.g. soot, metal oxides, minerals)
• Toxic or harmful dusts (e.g. silicate dusts, certain metal dusts)
• Less toxic/non-toxic dusts (e.g. sugar dust, lime dust)

The particle size, surface structure and chemical composition significantly influence the reactivity and the effect on humans and the environment.

Despite the health risks, ultra-fine particles are used in a targeted manner:

• Medical inhalation therapy:
  Ultra-fine particles serve as a carrier for active pharmaceutical ingredients such as corticosteroids for the treatment of respiratory diseases. For example, special milk derivatives (e.g. from Meggle) are used as carrier substances to ensure efficient inhalation and absorption of active ingredients.
• Pigment and colour industry:
  Industrial carbon black, produced by pyrolysis, is widely used as a black pigment in printing inks, toners, paints and for colouring rubber tyres. Carbon black is optimised for further processing through agglomeration processes (e.g. dry pearling or wet pearling).
• Further fields of application:
  • Production of catalysts
  • Battery technology (e.g. active materials in lithium-ion batteries)
  • Cosmetics industry (e.g. fine pigments in make-up products)
  • Food technology (e.g. carrier substances for flavours or additives)

Requirements for process engineering equipment in ultrafine particle processing

When handling products containing fine dust, process systems must fulfil the highest requirements:

• Gas tightness:
  Apparatus must be designed to be permanently gas-tight, especially with alternating pressures (vacuum/overpressure) and rotating mixing tools.
• Sealing technology:
  Depending on the type of dust and industry requirements, amixon® utilises different sealing concepts:
  • Dry shaft seals (standard for less critical applications)
  • Gas gap seals (enable contactless sealing on the product side, but require additional dust extraction)
  • Mechanical seals (gas-purged or liquid-lubricated, ideal for the highest demands)
• OmgaSeal® technology (a special development from amixon® for permanently gas-tight inspection doors)

Ultrafine particles are ambivalent substances: On the one hand, they enable innovative products and therapies; on the other hand, they harbour considerable risks for health and technology. Therefore, the utmost care must be taken when selecting process engineering solutions and, in particular, sealing systems. The customised concepts from amixon® ensure safe, efficient and sustainable handling of dusty products.