Metal Cutting Fluid Purification and Waste Treatment
Metal cutting fluid is a common industrial fluid used for metal working and machining operations such as drilling, tapping, deep hole boring, and gear and bearing machining. It is used to reduce friction and wear, remove heat generated by the process and reduce stress caused by the cutting process. It also reduces tool wear, resulting in improved surface finish and longer tool life.
Metal cutting fluid is typically composed of a base lubricant that contains emulsifiers, biocides, and a wide range of other additives. These fluids can also contain acids, alkalis, and solvents to provide greater lubrication, cooling and cleaning. Although these fluid formulations are designed to provide the optimum performance while being safe to the environment and operators, the materials used in metal cutting operations can cause fluids to deteriorate, creating a need for continuous fluid purification and waste treatment process.
The most effective way of purifying metal cutting fluid is through a cycle of filtration and centrifugation. In filtration, suspended particles, such as swarf and cutting lubricants, are collected on the filter medium. This method can be used to remove particles as small as 1 micron in size. Regular maintenance of filters is important to ensure effective filtration. Centrifugation, on the other hand, involves the separation of two immiscible phases in a fluid. This process can be used to separate the contaminants from the metal cutting fluid, allowing for its reuse.
The waste created by metal cutting operations is mainly composed of swarf and cuttings lubricant. As a result, fluid waste disposal can be difficult and potentially hazardous. It is important to ensure that the waste is adequately treated before being discharged into the environment. The most commonly used treatment process for metal cutting fluid waste is oil removal. This process removes the contaminants by fractional distillation, extracting the lubricant components of the waste stream while leaving the inorganic compounds. It is important to ensure that the waste oil is subsequently disposed of properly in accordance with environmental regulations.
Another method used to treat wastes resulting from metal cutting operations is biological treatment, which is generally used to treat wastewater contaminated with oil and grease. This process uses micro-organisms in an aerobic environment to break down the contaminants and turn them into harmless products. This process also reduces odor, resulting in clearer and less polluted waste water.
In addition to the above stated methods, physical-chemical treatment processes are also used for the treatment of metal cutting fluid waste. This process combines a series of operations including filtration, sedimentation, flotation and electrokinetic deposition. The application of physical-chemical techniques has proven to be very successful for treating wastewater containing high amounts of oil, grease and other suspended solids.
These are the most commonly used techniques for purification and waste treatment of metal cutting fluids. It is important to select the appropriate method for the purification and treatment of metal cutting fluid to ensure the safety of operators and the environment. Furthermore, proper filtration and regular maintenance is essential to extend the life of metal cutting fluids and reduce waste.
