Study On The Hot-Reclamation Technology Of Used Resin Sands

The used sands may not be re-used if they are not reclaimed. As hundreds and thousands of the used sands were thrown off as solid waste, the high quality silica sand resource was wasted seriously, and the environment and under-water was also polluted. Thus, it has great value for protecting the environment and natural resource to reclaim and utility the used resin sands.In this paper, the heating temperature, the heating processes, the heating equipment and the foundry process properties of the hot-reclaimed sands were researched through theory analysis and experiment. Conclusions have been drawn as follow.The loss of Ignition of the pre-coated sands, the hot core-box sand and the ester hardening alkaline phenolic resin sands was determined at different heating temperature and time during experiment. The curves of the loss of ignition and temperature were given. The micro-feature of surface of the three kinds of sands hot-reclaimed at the different temperature and time was observed by cubic microscopy, so the adaptable heating temperature and time had been fixed. For the ester hardening alkaline phenolic resin sands, the sands can be heated at 500℃ for lOmin or at 600℃ for 5min. For the pre-coated sands, it will cost 5min to hot-reclaim the sands at 600℃. For hot core-box sands, when the temperature is 500 ℃, it needs 15min, wherever, when the temperature is 600 ℃, it needs 5min.The processing properties of the hot-reclaimed sands had been researched. Compared with the new sands, the shape of the hot-reclaimed sands is more round, the piled-density increases slightly, the gas of combustion and the hot-expansibility decreases, the tensile strength of samples of the hot-reclaimed sands improves. The processing properties of the hot-reclaimed sands are prior to that of the new sands.Based on the technology of fluid-bed, the fluid-bed, under witch oil is burning, is adopted as the hot-reclaiming equipment for the used resin sands. The structure of the equipment was designed, the reclaiming process is fixed, and the main technical of the equipment were also calculated. The heat consumption is 577387kW/t, the electric energy consumption is12kW/t, the temperature of the exhausted gas is 100 ℃, all of them are prior to that of the same abroad. The foundry process properties of the reclaimed sands satisfied the anticipated results.Exhaustion of the used sands and the consumption of the new sands are reduced through the hot- reclamation of the used sands. Thus, the environment and the natural resource are protected, witch brings in great society value. The works will profile Y1570240 per year with a fluid hot-reclaiming equipment of the used resin sands. The application of the hot-reclamation technique is consonant with the continuously growing stratagem, the equipment has bright prospect of market.