Chromgerbung

Chromgerbung, commonly known as chrome tanning, is a method of tanning animal hides using chromium(III) salts. It is the most widely used tanning method in the leather industry, producing leather with high resistance to water, heat, and microbial decay, and with stable shape and pliability.

During chromgerbung, hides are first prepared through cleaning, liming, and sometimes pickling. They are then treated with chromium salts in an acidic or mildly acidic bath, allowing chromium ions to coordinate with collagen molecules in the dermal connective tissue. The process forms cross-links that convert the collagen into a durable, water-insensitive matrix. After tanning, the leather is neutralized, often retanned for color and properties, dyed, and fat-liquored as needed.

Advantages include faster processing compared with vegetable tanning, more uniform softness and color, and higher hydrothermal stability, enabling use in a wide range of products from footwear to upholstery. Chrome-tanned leather tends to have better shrinkage resistance and can be produced in various thicknesses and finishes, offering consistent performance and process efficiency for large-scale production.

Environmental and health considerations concern chromium species management. The main environmental risk is chromium-containing effluent; modern chrome tanning uses Cr(III) and minimizes oxidation to Cr(VI) through process control, wastewater treatment, and chromium recovery. Regulations in many regions govern chromium release and worker exposure. Alternatives such as vegetable tanning and synthetic tanning are used to reduce chromium use.