Dry additives in powder condition like manganese, lime, coal and iron oxide are added to raw materials as well as to the semi-finished product. Wet additives in slurry condition like engobes are sprayed onto the product.

De Boer Machines supplies additive feeding installations of all kinds.

Examples are a stain feeding installation which transports the powder directly from a silo through an extraction auger and intermediate hopper to a micro feeder. The stain powder can also be transported form a big bag or silo by means of a pneumatic transport system executed with a send and receive tank.

De Boer Machines developed vibrating gutters equipped with a loss-in-weight controlled systems. This system is especially suitable to dose very small amounts of additives intermittent to the product.

The latest development in the field of additive feeding is the use of electro-static techniques. This enables it to cover moulding surfaces with very thin layers of powder, very accurately.

De Boer Machines supplies also powder coloring equipment which can mix several stains and dose the mixture into the clay feed. The stains are mixed with the clay in the mixer for a uniform mixture. The dosing can be equipped with a lost in weight control system.