High-quality walnut shell sanblasting should be made from premium walnut shells, processed through crushing, polishing, steaming, chemical treatment, and multiple screening steps. Walnut shells is not only wear-resistant and pressure-resistant, but also insoluble in acidic or alkaline water, exhibiting strong interception capacity and rapid filtration speed. After undergoing special processing (removing pigments, fats, oils, and charged ions), the walnut shells possesses excellent properties in water treatment, including strong oil removal performance, removal of solid particles, and easy backwashing, making it suitable for treating oily wastewater from oil fields.
Characteristics of walnut shell sanblasting:
Walnut shell sanblasting is a new generation of abrasive that replaces quartz sand abrasive, improving water quality and significantly reducing water treatment costs. It has stronger compressive strength; according to relevant test data, walnut shell particles with a diameter of 1.2-1.6 mm have an average compressive strength limit of 0.2295 KN (23.40 kgf), while those with a diameter of 0.8-1.0 mm have an average compressive strength limit of 0.165 KN (16.84 kgf). Furthermore, walnut shell sanblasting is chemically very stable, contains no toxic substances, and has very low solubility in acids, alkalis, and water. The loss of walnut shells in hydrochloric acid solution is 4.99%, and in sodium hydroxide solution, the loss rate is 3.8%, meaning it will not cause water quality deterioration.
Uses of walnut shell sanblasting:
Walnut shell sanblastings, as a filter media, possess the ability of ordinary filter media to intercept contaminants, directly trapping suspended particles in wastewater. Furthermore, walnut shell filter media, relying on its unique surface physicochemical properties, can remove emulsified oil particles from oilfield wastewater by adsorbing them onto the filter media surface or onto surface aggregates through adhesion.
The use of walnut shells as an adsorbent has been scientifically proven. However, the viscosity and surface tension of oil inversely affect the adsorption rate of walnut shells. Moreover, the recovery of oil from walnut shells is significantly higher than with other water media, achievable simply through compression. Walnut shell filter media is also suitable for filtering pre-treated well-washing wastewater.
