The grinding

Grinding is the second step of comminution. This process deals with material that has already been reduced (<10 mm) and brings particle sizes up to micrometric dimensions. It is used in dry or wet processing (pulp).

Different techniques implement breaking principles such as compression, impact, attrition and abrasion to varying degrees. This operation, pushed forward through to micronization, at an extreme can lead to the amorphization of crystalline structures (mechanochemistry) to make the materials functional (manufacture of new binding, activation, etc.).

The most-used mills are ball mills, although CTP has a wide range of grinding techniques available to suit the characteristics of the material and the operational requirements:

GRINDING
Type	Materials	Particle size In (d₁₀₀)	Particle size Out (d₅₀)	Capacity
Vertical shaft vibration mill	Semi-hard, soft and crumbly	0-2 mm	0-30 µm	Batch 2 kg
Vertical shaft vibration mill	Semi-hard, soft and crumbly	0-2 mm	0-30 µm	100 kg/h
Ball mill	Hard, abrasive and crumbly materials	0-4 mm	0-60 µm	Batch 23 L
		0-4 mm	0-60 µm	Batch 65 L
		0-5 mm	0-60 µm	100-250 kg/h
		0-3.36 mm	0-200 µm	12 kg (Work index Bond)
		0-2 mm	0-40 µm	2-4 kg
		0-2 mm	0-40 µm	200 kg/h
		0-10 mm	0-50 µm	50 kg/h
Rod mill	Hard, abrasive and crumbly materials	0-20 mm	0-1 mm	Batch 2 kg
Rod mill	Hard, abrasive and crumbly materials	0-30 mm	0-2 mm	200 kg/h
Disk mill	Hard and abrasive materials	0-25 mm	0-5 mm	30-500 kg/h
Impact mill	Semi-hard to soft	0-20 mm	Screen 8 mm to 80 µm	0-100 kg/h
Hammer mill	Soft, crumbly and fibrous materials	0-30 mm	0-100 µm	1 t/h
Semi-autogenous mill	Hard, abrasive and crumbly materials	0-10 mm	0-0.5 mm	200 kg/h
Pin mill disintegrator	Soft, dry materials	0-2 mm	0-100 µm	50-100 kg/h
Pin mill disintegrator	Soft, dry materials	0-10 mm	0-100 µm	500 kg/h

MICRONISATION
Jet air mill	Semi-hard and crumbly	0-1 mm	0-5 µm	1-2 kg/h
Vibromill	Hard to soft	<10 mm	0-50 µm	50-100 cm³
Planetary mill	Hard to soft	0-3 mm	<30 µm	50 cm³