Preparation and Performance Optimization of Organosilicon Slag Exothermic Insulating Riser

Abstract

The exothermic insulating riser played an important role in the solidification process of metal liquid for the improvement of casting quality. This paper focused on the use of organosilicon slag to replace part of the aluminum powder as an exothermic agent for the riser, to reduce production costs and turn waste into treasure. The experiments firstly studied the effect of organosilicon slag content on the combustion temperature and holding time and determined the components of the riser exothermic agent and organosilicon slag. On this basis, the effects of the content of Na3AlF6 flux and alkali phenolic resin binder on the combustion heating time and strength properties of the riser were studied. And the ratio of mixed oxidants was determined by single-factor orthogonal experiments to optimize the addition of three oxidants, Fe3O4, MnO2, and KNO3. Finally, the performance of the riser prepared after optimization was compared with that of the riser prepared with general aluminum powder. The results showed that with the mixture of 21% organosilicon slag and 14% aluminum powder as the exothermic agent, the highest combustion temperature of the prepared exothermic insulating riser was 1451℃ and the holding time was 193 s; the optimal content of Na3AlF6 flux was 4%, and the best addition alkali phenolic resin binder was 12%; the optimized mixing ratio of three oxidants was 12% for Fe3O4, 6% for MnO2, and 6% for KNO3. Under the optimized ratio, the maximum combustion temperature of the homemade riser was 52℃ and the heat preservation time was 14% longer compared with the conventional exothermic insulating riser with 25-35% aluminum powder.

Exploration and Improvement of Room Temperature Properties for Organosilicon Slag Riser

“…SWY hydraulic universal testing machine was used to test the compressive strength of specimens; STD-III automatic electric permeability tester was utilized to measure the air permeability of specimens; HWP22-10S solid flash point tester was exercised to determine the flash point of organosilicon slag; SNB-2 rotary viscometer was employed to measure the viscosity of resol resin; Electric blast drying oven was exploited for heat treatment; Field emission scanning electron microscope was used to observe the microstructure morphology of specimens; LS-609 laser particle size analyzer was harnessed to analyze the particle size distribution of organosilicon slag [1].…”

“…The optimization method from the literature optimized the following: A-resin viscosity, B-resin addition, C-organosilicon slag addition, D-organosilicon slag particle size [1]. The orthogonal tests and the extreme value analysis were shown in Table 4 and Table 5, respectively.…”

“…It could be seen that the aluminum powder and resole resin have the highest costs among the riser materials. Under the condition that both risers could generate heat above 1500°C [1], the APR contained approximately 30% aluminum powder, 54.5% hollow floating beads, and 11% resole resin. In comparison, the OSR contained 14% aluminum powder, 21% organosilicon slag, 44.5% hollow floating beads, and 14% resole resin.…”

“…Previous studies had examined different aspects of performance. The effect of material composition and proportions on heating and insulation properties was studied [1], and the heat exchange coefficient between the riser surface and surroundings was evaluated [2]. Shrinkage defects could be influenced by different riser types in ductile iron castings [3].…”

“…However, the toxicity of the organosilicon slurry could be reduced through hydrolysis, and the added value of the organosilicon slag could be retained from the steam rinsing process, enabling resource utilization [5]. Previous experiments utilized the treated organosilicon slag to produce exothermic insulating risers, meeting the standards for conventional risers in terms of heating performance and insulation time while reducing production costs [1] . However, risers incorporating organosilicon slag displayed issues including low strength, high resin addition requirements, and easy ignition during drying.…”