TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The mass ratio of zinc oxide: glycerol: urea: Lewis base is 1:1-70:10-60:0-0.25, preferably 1:3-49:26-40:0-0.12. The Lewis base is oxalic acid, benzoic acid, salicylic acid, tartaric acid, carbonic acid, sodium salt of acetic acid, potassium, calcium hydrate, zinc acetate, zinc ammonium ion complex and/or zinc salt.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The solid-liquid separation is carried out by filtering, centrifuging or settling; where the filtering is done by using pressure filter, vacuum filter or mechanical filter; the centrifuging is done by using intermittent filtration centrifuge, continuous filtration centrifuge, centrifuge tube, disc centrifuge or centrifugal machine; and the settling is done by using three-foot settlement centrifuge, spiral discharging settling centrifuge or settlement machine.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method comprises: either adding the mixture of all the ingredients at one time; or adding zinc oxide, Lewis base and glycerin, and adding urea at the end of first reaction; or adding zinc oxide, Lewis base and part of glycerol, and adding urea reactor and glycerol, at the end of first reaction. The first reaction is carried out at normal pressure, at 80-280 degrees C, preferably 130-160 degrees C, and controlling the reaction time for 0.5-10 hours, preferably 1.5-3.5 hours. The second-stage reaction is carried out at 0-30 kPa, at 80-180 degrees C, preferably 0-10 kPa, at 130-160 degrees C, and then controlling the reaction time for 0.5-9 hours, preferably 3-5 hours. The separation process is carried out by atmospheric and vacuum multi-column distillation and simulated moving bed chromatographic separation. The solvent recovery process is distillation, flashing or any other solvent recovery process. Preferred Components: The precipitating agent is methanol, ethylene glycol, acetone, butanone, pentanone, hexane and/or cyclohexane. The removing agent is water, methanol, ethanol, acetone or a solvent capable of dissolving Lewis bases and urea, and which does not dissolve zinc glycerate. The simulated moving bed chromatographic adsorbent used for separation is silica gel, activated carbon or ion exchange resin. The eluent is methanol, ethanol, acetone, ethyl acetate, dichloromethane, cyclohexane and/or n-hexane.