Study On The Purification And Regeneration Equipment Of Metalworking Fluid

Currently, machining method both at home and abroad still adds great pollution to the environment. Untraditional dry cutting, the dry machining of jet cooling and liquid nitrogen cooled are the main processing methods, which have both advantages and disadvantages, therefore, it is quite difficult for us to replace the dry machining with wet machining of water-based cutting fluids, the development of high performance green environment-friendly water-based metal cutting fluid is still of great importance. Despite of the gradual maturity and quantity of the methods of dealing with the sewage of metalworking fluids, they invariably result in the loss of a large number of effective components in metal processing fluid, it is significant for us to research a low treatment cost, energy saving, harmless to human, environment-friendly method.In view of the failure for metal processing fluids, the renewable metal processing fluid purification equipment is designed after investigation and analysis, which not only lows the cost of wastewater treatment, but also achieves energy conservation and emission reduction, even contributes to the environment, that is to say, killing three birds with one stone. The regeneration of metal processing liquid purification is mainly divided into water conditioning system, dissolved air outgassing system, ozone ultraviolet disinfection system, hetero-coagulation flotation system and slag drainage system, among them, dissolved air outgassing system uses firstly ozone then air as dissolved air; hetero-coagulation flotation system is a secondary flotation system, the primary separation zone and the secondary separation zone corresponding to the two sets of coagulant dosing line; sterilization methods combines the effects of ozone and ultraviolet.In commissioning period, the renewable metal processing fluid purification equipment is continuously running, the inflow of metal processing fluid is 600 L / h, the cycle period is 1 hour. The air inflow of ozone or air in dissolved air system is 7%; the inflow of the total dissolved air water is about 350L/h, including 210L/h in primary separation zone and 140L/h in secondary separation zone; the pressure of dissolved air pump is 0.5 MPa, the equipment circularly runs 5 hours, a sample is taken per cycle(namely a sample is taken per hour), by detecting pH, conductivity, COD, total bacteria, oil content, suspended solids and other indicators of processing liquids, the optimum time of the equipment is determined by 2 hours. After the renewable metal processing fluid purification equipment has circulated and purified 2 hours: the outflow pH is stably around 8; In the process of purification, processing liquid conductivity is almost stable; the loss ratio of outflow COD is less than 10%, the sterilization rate can reach 99.6%; the removal rate of outflow oil content can reach 90% or more, the removal rate of suspended solids can reach 95%; filtering performance is far better than raw water; the color changes from white to milky white and the unpleasant odor disappears. According to the national standard method of testing, the metal processing liquids which have been purified and regenerated meet GB6144-85, including the storage stability, pH value, antifoaming performance, anticorrosive performence, antirust and other performances.Experimental results show the feasibility of the method, which purifies the metal processing liquids by ”the secondary coagulation floatation separation technology & ozone ultraviolet sterilization”. Based on this method to design and develop, the renewable metal processing fluid purification equipment proves to be effective if the outflow meets the standard.