Study On Regeneration Technology Of Waste Clay By Ultrasonic-assisted Solvent Extraction

Along with the increased demand for the lubricating oil in our country, the amount of waste clay generated in the lube refining process is also increasing. The waste clay contains about twenty percent ideal components and ten percent unideal components of the lubricant base oil. Serious environmental pollution and resource waste will happen if the waste clay couldn’t be handled in a reasonable way. Therefore, the regeneration of the waste clay and oil recycling has both economical and environmental meaning.Present technology for waste clay regeneration couldn’t completely achieve oil recycle and the recovery of the adsorption activity of the waste clay. This paper used the Liude refining waste clay as the study object. With the assistance of ultrasonic and solvent extraction, this paper found a proce`1ss which could not only realize sufficient oil recovery but also assure the adsorption activity of the reactivated clay under certain experimental conditions.The nonpolar solvent and polar solvent was used as the extraction solvent in this paper to extract ideal component and unideal component of the lubricant oil in the waste clay respectively. The pore structure of the waste clay was unclogged by sulfuric acid washing and the regenerated clay was obtained after rinsing and drying.This paper obtained the optimum processing conditions for waste clay regeneration through experiments under different conditions. The optimum conditions for ideal oil recovery were as follows: If the mass of the waste clay is 100 g, the nonpolar solvent is petroleum ether(90-120℃), the dosage of the petroleum ether is 60 ml, the ultrasonic frequency is 68 K Hz, the extraction temperature is 30℃, the extraction time is 10 min for one time. The optimum conditions for the unideal oil recovery were as follows: the nonpolar solvent is petroleum ether(90-120℃), the dosage of the petroleum ether is 60 ml, the polar solvent is ethanol(95%), the dosage of it is 15 ml, the ultrasonic frequency is 68 KHz, the extraction temperature is 30℃, the extraction time is 10 min, the above treatment cycles number was three. Then we replace mixed solvent with 100 ml 95 % ethanol and extract the unideal oil for one time with the above conditions. The optimum process conditions for sulfuric acid washing is as follows: the solid/liquid ratio(mass ratio) is 1:2, the sulfuric acid concentration is 10%, the washing time is 2h, the washing temperature is 100℃.The investigation of the properties of the regenerated clay and ideal oil showed that the property of the regenerated clay could reach the property standard for oil refining clay and the ideal oil could reach the performance standard for lubricant base oils. Meanwhile the refining capacity of the regenerated clay was close to the fresh clay. This paper not only achieved the activity recovery of the waste clay but also sufficiently recycled the oil contained in the waste clay as expected.