Flame retardants

Minerals as fillers are becoming increasingly important

The increase of fire safety is a hot topic. It is especially halogenated and brominated flame retardants that are both harmful to the health and also the environment, and they are for the most part prohibited in Europe. Mineral substitute additives are being used more and more. The demand here is mainly for aluminium hydroxide and magnesium hydroxide because of their unique properties: under elimination of water, these substances have a cooling and gas-thinning effect – already at temperatures below 200° C.

These flame retardants are used as protection for buildings, in plastics, electronic devices and textiles, whereby for each of these applications, different fineness values and particle properties are required. An additional challenge is to make sure that the end products do not get discoloured as the result of iron contamination.

Special particle size distributions and particle structures

achieved by fine grinding and classifying

Specific particle size distributions are required dependent on the application. In order to achieve the perfect particle size distribution, different grinding systems with integrated classifiers are employed.

Alpine table roller mill AWM for fineness values of d₉₇ = 20 µm to d₉₇ = 63 µm
Alpine ball mills with TTD classifiers in circuit for fineness values of d₉₇ < 8-10 µm
Alpine wet agitated media mill ANR for fineness values of < d₉₇ < 6 µm

With every particle size distribution, it is important that it is as steep as possible, i.e. that as few interfering fines are present. This is possible with the described grinding systems without the need for a downstream de-dusting step.

Grinding with no iron contamination thanks to the ideal wear protection of our systems prevents an undesirable discolouration of the end product.