The CEMTEC pilot plant has a large number of individual machines for conducting tests from batch grinding through to continuous grinding tests on a semi-industrial scale. As batch grinds always provide only a partial result or a parameter and do not map the entire continuous process, we perform continuous grinding tests.

The available grinding circuits allow us to cover a very broad spectrum of comminution. The following equipment is available for such grinding tests:

• Ball mill "DORIS" (dry and wet)

• Rod mill "WALBURGA" (dry and wet)

• Wet mill "OLGA" (dry and wet)

• Vertical roller mills "STEFANIA", "BARBARA", "ANDREA"

• Batch mills "ELLA", "RESI", "FIFFI", "GRETCHEN", "MINNA" (dry and wet)

**Ball mill "DORIS" – Rod mill "WALBURGA"**

This semi-industrial plant offers the greatest possible flexibility in regard to product development and optimization of the grinding circuit as well as the production of greater product quantities.

The basis of this plant is a ball mill with

Diameter: 1.2 m

Grinding path length, variable: 1.8–3.0 m

Installed drive output: 55 kW

Type of discharge: peripheral or grate discharge

Depending on the objective, this mill is integrated in the grinding circuit as a ball mill or rod mill.

The grinding plant has the following characteristics:

• Feed: can be assembled from a material mix of up to three components.

• Classification: two air classifiers of the latest generation

• Product separation of the material: via pulse bag filters

• Circuit load determination: via mass flow weighing in circulating flow

• Continuous sampling points

• Complete process monitoring and evaluation of all relevant and characteristic parameters

(power, temperature, mass flow rate …)

**Wet mill "OLGA"**

The ball mill "OLGA" is used at CEMTEC to grind smaller product amounts in a continuous circuit.

The mill has the following technical data:

Diameter: 0.6 m

Grinding path length, variable: 0.7 m

Installed drive output: 11 kW

The mill is typically operated using a hydro-cyclone with a diameter of 2" in the circuit. The fresh material is fed in via a screw conveyor.

**Vertical roller mill "STEFANIA"**

A total of three different vertical mills, in the form of vertical roller mills, are in use in the CEMTEC pilot plant. The largest of these is the vertical roller mill "STEFANIA", which has a disc diameter of 670 mm. The mill can be operated with a hot gas generator so as to combine the process steps grinding and drying in one step. The mill is equipped with the latest generation of turbo-classifier, which is operated with a nominal air flow of 5000 Bm³/h. Products with d98 = 6 µm (based on calcium carbonate) can be produced here. As a special feature the coarse fraction of the air separator can be discharged out of the mill.

**Available batch mills**

A total of five batch mills are in service, these being used for product generation and identification.

• Batch mill "RESI" ø 0.3 x 0.6 m (rod mill), minimum required sample quantity 15 kg

• Batch mill "ELLA" ø 0.3 x 0.3 m (ball mill), minimum required sample quantity 15 kg

• Batch mill "MINNA" ø 0.8 x 0.9 m (ball mill), minimum required sample quantity 70 kg

• Batch mill "FIFFI" ø 0.5 x 0.4 m (ball mill), minimum required sample quantity 20 kg

• Batch mill "GRETCHEN" ø 0.5 x 0.4 m (ceramic mill), minimum required sample quantity 20 kg