Screening of silicon powder - but please make it hydrogen-tight

19.09.2024, Remscheid, Germany

Valentina Weber, RHEWUM GmbH

Screening the finest silicon powder requires the highest purity standards. Not challenging enough? Then make it gas-tight for hydrogen! This is how it works:

The highest purity standards are required for the sieving of high-purity silicon powder, which is used in chip and solar panel production. Even the smallest impurities can have serious consequences for the quality of the end product. RHEWUM has risen to this challenge and supplied three RHEsono^® screening machines that have been specially developed for screening the finest silicium powder. The focus here was on a special technical requirement: hydrogen tightness.

One of the biggest technical challenges was that the screening machines had to be gas-tight, in particular hydrogen-tight (H2-tight). In a hydrogen atmosphere, the hydrogen protects the sensitive silicon powder from unwanted chemical reactions that could be triggered by metal ions (hydrogen passivation). This protective effect is crucial to ensure the high purity of the end product.

However, the extremely small hydrogen molecules can pass through steel and cause hydrogen embrittlement, which makes the material fragile and jeopardizes its structural integrity. To prevent this, the RHEsono^® machines have a special plastic coating on the inside. This coating protects the inside of the machine and prevents the hydrogen from weakening the steel. For components that could not be coated, a nitriding process was used to make them resistant to the effects of hydrogen.

Thanks to the hydrogen-tight design and a static housing with fixed flange connections, it was possible to operate the machines under an overpressure of 0.5 bar without the risk of leaks, material damage or explosion hazards whilse ensuring safe operation in accordance with ATEX directives. This precise sealing guarantees that neither hydrogen escapes nor external impurities enter the process, keeping the purity of the silicon powder at the highest level.

Effectiveness of RHEsono^® screening machines

The RHEsono^® machines from RHEWUM are equipped with a special vibration technology that transfers enormous forces directly to the screen mesh. As a result, adhesive forces between the silicium particles are effectively released, which significantly increases screening efficiency. The result is an extremely precise separation with a purity that meets the highest requirements.

Additional advantages of the RHEsono^®:

• ATEX-certified: Safe operation in potentially explosive atmospheres
• Self-cleaning mechanism: Increases efficiency and reduces maintenance requirements
• High reliability & durability: Robust design for long-lasting performance
• Low energy consumption: Efficient operation reduces operating costs

The combination of precise technology and exceptional purity levels makes these machines ideal for processing sensitive materials such as silicon powder.

Are you also facing a tricky challenge with your screening process? Contact us - we will find the right solution for your requirements.