Cryogens can be an effective way to reduce the size of materials that cannot be ground under normal conditions. Many materials that are resilient at ambient temperatures become brittle and glass-like under low temperatures. As a result, these materials can be pulverised through impact or shearing. This form of grinding can also be used to create unusual particle shapes or sizes.
Various materials are suited to cryogrinding. For instance, materials that are tacky or oily can often be solidified and ground. Products that are heat-sensitive can be processed at a temperature level that allows them to be ground without degrading or melting. In addition, cryogenic impact can debond multicomponent materials such as chrome-plated ABS (plastic). And spices can be ground without loss of volatile oils and flavours, thus preserving and enhancing their quality.
Choice of cryogrinding agents
The most widely accepted refrigerant for cryogrinding is liquid nitrogen (-196°C). Unlike CO2, liquid nitrogen (LIN) does not go through a solid phase, instead transitioning directly to a gaseous state. LIN can thus be directly injected into a grinding mill. During the solid-to-gas phase change, it produces a powerful cooling effect on the product. Solid carbon dioxide (also known as dry ice) or liquid CO2 can also be used as grinding coolants if temperatures below -78°C are not required.
We deliver a tailored, dedicated supply concepts for cryogrinding installations, extending from gas supply and storage systems through supply lines to pressure and temperature control solutions.
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