As a manufacturer of concrete products one is often faced with request for black concrete – not just anthracite. Permanent supposedly black coloring is obtained only with Iron Oxides or with Carbon Blacks. Advantages and disadvantages are found in both variants.

he Iron Oxide, the safe version of a black coloring unfortunately, does usually not achieve the desired color intensity, even at high doses, despite further developments of some products on the market. Anthracite colors are avaiable that are stable and durable.

With the use of Carbon Blacks a deeper blackening can be achieved. Due to only mechanical anchoring in the concrete, the blackness and the durability are extremely dependent on the particle size and the raw material mix for the production of carbon. Necessary for the anchorage would be a high particle size (at least 70 nm). The particle size increases inversely proportional to the color strength. The commercially available products are 70 nm up to almost 300 nm in size.

A third variant is the coloring of an Iron Oxide/Carbon Black mixture. Here one tries to combine the advantages of the Iron Oxide (durability) with that of Carbon Black (coloring) and makes use of an reassurance to avoid the complete bleaching of the products by the Iron Oxide.

From purely economic and environmental point of view, however, all three variants are sometimes seen to be critical – especially in the range of Carbon Black is the product almost only offered in the modifications of granule or liquid. The energy expenditure is especially immense in production of some soot granules and is not always proportionate to the benefits. First you put much energy into it to granulating Carbon Black in order to then destroy the granules with a lot of energy during the mixing process again.

Costs for coloring could significantly be reduced with the latest high quality Carbon Black from BPS GmbH out of our product line – Pechschwarz Intensiv. The product provides beside the required particle size an unrivaled color strength. This is reqched by particle size, the selected raw material mix and a special production process. The results allow architects and concrete producers to truly speak of pitch black concrete products.