1. Water removel: collect used oil to oil pool after dewater, placed in the oil refining pot, heat up to 70 ~ 80 ℃ after stop heating, and let it rest for 24 hours, row out surface water, and then slowly heat up to 120 ℃ (when the oil temperature is close to 100 ℃.
2. Acid pickling: stay oil cooled to room temperature, under the stirring slowly add sulfuric acid levels (about 92 ~ 98%), the dosage of acid for oil commonly 5 ~ 7% (according to degree of oil dirt).Half an hour after adding the acid, continue to stir, and then let it stand for 12 hours, the acid slag line.
3. Alkaline wash: after pickling oil to heat up to 80 ℃, adding soda ash (Na2CO3) under stirring, after fully stir well, let it stand for an hour, and then use dipstick test to neutral, then let stand for more than 4 hours, the alkaline row
4. The activated clay adsorption: heat oil to 120 ~ 140 ℃, under constant temperature and stirring to join activated clay used about 3.5% of the oil amount, after adding the activated clay, continue to stir in half an hour, in 110 ~ 120 ℃ under constant temperature static overnight, the next day strike filter.
5. Filter: use filter oil machine to filt oil