Services a-z > Blast cleaning with silica-free abrasive

Blast cleaning with silica-free abrasive

The abrasive we use to remove defective, porous slag from the tubes of slag tap boilers does not contain any free silica, which means it does not pose a health risk. It is ideal for finishing and deburring metallic components with minimum damage to surfaces. In comparison to most chemical procedures, blast cleaning is environmentally friendly and, thanks to the reduced dust exposure, it’s safer too.

Our process: high-pressure compressors, a blasting machine, and a hose and nozzle (8–12 mm, tailored to the task in hand), create a pressure of 8 bar. The machine blasts the abrasive through the hose, so it impacts the surface in a circular beam with a diameter of 3 centimetres at speeds of 12–200 metres per second, removing the slag. Different types of abrasives can be used, such as Siligran, chilled cast iron grit, walnut shells, duroplast, glass beads, sintered corundum, and sand.

A single blasting machine in use for 10 hours consumes on average three tonnes of abrasive, although obviously the precise amount will depend on how firmly the slag is attached to the boiler surface. Any abrasive secondary waste created is removed by a suction vehicle and taken to a waste disposal facility, or incinerated in the boiler’s combustion system.

Blast cleaning offers many benefits: it allows the slag to be completely removed without damaging the surface below, and can be adjusted to suit the area in question. A rough blasting of the slag makes it possible to establish the current state of the combustion chamber and to clean away any baked-on debris. It clearly identifies any cracks, porous surfaces or missing pins – making it easier to take precise measurements and carry out repairs effectively.

Benefits at a glance

• Quickly cleans damaged surfaces 
• Removes defective slag in a controlled manner
• Technical expertise in tailoring blasting machine to specific requirements
• Silica-free abrasive
• Different types of abrasive available depending on requirements

Exposing damaged areas.