염기성 폴리올 및 식용유 정제에 사용하는 합성 규산마그네슘의 효율성은 정제능력과 여과속도를 통해 평가되며, 규산마그네슘의 입도 및 표면적에 따라 영향을 받는다. 본 연구에서는 합성변수인 반응온도, 주입속도, 주입순서(Si, Mg), Mg/Si의 반응몰비가 규산마그네슘의 입도에 미치는 영향을 조사하였다. 합성된 규산마그네슘은 합성공정, 분쇄공정, 정제공정으로 비교 분석되었다. 합성공정에서 반응 온도와 주입 속도는 규산마그네슘의 평균입도 변화에 영향을 주지 않는 반면, Mg/Si의 반응몰비와 주입 순서는 평균입도 변화에 주된 요인으로 작용하였다. 합성 후 규산마그네슘의 평균입도는 반응몰비가 0.125에서 0.500로 증가할 때 Mg 주입 시 약 54.4 μm에서 63.1 μm로 약 8.7 μm 증가하였고, Si 주입 시 47.3 μm에서 52.1 μm로 약 4.8 μm 증가하였다. 주입 순서 별 평균입도를 비교해보면 Mg 주입 시 59.1 μm, Si 주입 시 48.4 μm로 약 10.7 μm의 평균입도 차이를 보였으며 Mg을 주입하는 조건에서 약 2배 빠른 수세여과속도가 관찰되었다. 즉, 입도가 증가함에 따라 여과 시간이 단축되고 수세여과속도 증가로 생산성 향상에 기여할 수 있었다. 여과 후 분리된 cake형태의 규산마그네슘은 건조과정을 통해 단단한 고형체가 되고 분쇄공정을 통해 분말형태의 흡착제로 사용된다. 건조된 규산마그네슘의 물리적 강도가 감소함에 따라 분말의 평균입도가 감소하고, 이 강도는 반응몰비에 영향을 받는 것을 확인하였다. Mg주입 시 Mg/Si의 반응몰비가 증가함에 따라 규산마그네슘의 물리적 강도가 감소하여 분쇄 후 평균입도가 합성 후 평균입도에 비해 약 40% 감소하는 것을 관찰하였다. 이러한 강도감소는 평균입도 감소와 분쇄 후 미분량의 증가로 정제능력의 향상을 가져왔지만 정제여과속도 감소를 가져왔다. Mg 주입 시 반응몰비가 0.125에서 0.5로 증가할 동안 정제능력은 약 1.3 배가 증가하였으나 정제여과속도는 약 1.5 배가 감소하였다. 따라서 규산마그네슘의 생산성 향상을 위해서는 Mg/Si의 반응몰비를 증가시켜야 하지만, 폴리올의 정제여과속도를 증가시키기 위해선 반응몰비를 감소시켜야 한다. 규산마그네슘의 합성변수 중 주입순서와 Mg/Si의 반응몰비는 합성 후 평균 입도와 분쇄 후 평균입도 및 미분량 변화에 영향을 주는 주요인자로 생산성 및 정제능력을 결정짓는 중요한 합성변수이다.

The efficiency of the synthetic magnesium silicate used in basic polyols and edible oil purification is evaluated by its purification ability and filtration rate and is affected by the particle size and surface area of magnesium silicate. In this study, it was investigated the change on the particle size of magnesium silicate was influenced by the reaction temperature, injection rate, injection order (Si, Mg) and Mg/Si reaction mole ratio. The synthesized magnesium silicate was compared and analyzed for the synthesis, grinding, and refining processes. In the synthesis process, the reaction temperature and feed rate did not affect the average particle size change of magnesium silicate, while the reaction molar ratio of Mg / Si and the order of injection acted as main factors for the change of average particle size. The average particle size of magnesium silicate increased by 8.7 μm from 54.4 μm to 63.1 μm at Mg injection when Mg molar ratio increased from 0.125 to 0.500, and increased by about 4.8 μm from 47.3 μm to 52.1 μm at Si injection. The average particle size according to the order of injection was 59.1 μm for Mg injection and 48.4 μm for Si injection and the difference was shown 10.7 μm, therefore the filtration rate was about 2 times faster under the condition of Mg injection. That is, as the particle size increases, the filtration time is shortened and washing filtration rate can be increased to improve the productivity of magnesium silicate. The cake form of separated magnesium silicate after filtration becomes a solid through drying process and is used as powdery adsorbent through the grinding process. As the physical strength of the dried magnesium silicate increased, the average particle size of the powder increased and it was confirmed that this strength was affected by the reaction molar ratio. As the reaction molar ratio of Mg / Si increased, the physical strength of magnesium silicate decreased and the average particle size after grinding decreased by about 40% compared to the average particle size after synthesis. This reduction of strength resulted in an improvement of the refining ability due to the decrease of the average particle size and the increase of the amount of fine particle after the pulverization, but it resulted in the decrease of the purification filtration rate. While the molar ratio of Mg/Si was increased from 0.125 to 0.5 at Mg injection, the refining ability increased about 1.3 times, but the purification filtration rate decreased about 1.5 times. Therefore, in order to improve the productivity of magnesium silicate, the reaction molar ratio of Mg / Si should be increased, but in order to increase the purification filtration rate of the polyol, the reaction molar ratio should be decreased. In the synthesis parameters of magnesium silicate, the order of injection and the reaction molar ratio of Mg / Si are important factors affecting the changes in average particle size after synthesis and the changes of particle size after grinding due to the changes of compressive strength, therefore the synthetic parameter is an important thing that determines productivity and refining capacity.

Magnesium silicate Polyol Purification Particle size Reaction condition

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