고령토의 염산침출 슬러리를 25-60℃, 1-5 기압 범위에서 가압여과시켰다. 염산침출 전 고령토를 700℃에서 1시간 하소시키는 경우와 하소하지 않고 직접 염산침출시키는 경우에 대한 여과속도를 비교하였다. 25℃에서 여과시 고령토의 하소여부가 여과속도에 큰 영향을 주지 않았으나, 여과온도가 60℃로 증가되면서 하소시킨 고령토의 경우 여과속도가 보다 높은 것으로 나타났다. 압력이 1에서 5 기압으로 증가되면서 케이크 저항은 하소했을 경우 8.1×10¹⁰에서 9.3×10¹⁰(m/kg), 하소하지 않았을 경우 1.11×10¹²에서 6.37×10¹²(m/kg)으로 증가하였다. 여과케이크의 함수율은 여과압력 1기압에서 하소한 고령토의 경우 1.24(g water/g dry solid), 하소하지 않은 고령토의 경우 1.12(g water/g dry solid)이었다. 고령토의 하소 여부에 관계 없이 함수량 만큼의 세척수를 사용하여 3회 세척함으로써 케이크의 세공 사이에 남아 있는 알루미늄의 90-93%를 회수할 수 있었다.

Pressure filtrations of the slurry resulted from HCl leaching of a clay have been carried out at temperatures between 25 and 60℃ with the pressure varied from 1 to 5 atm. The filtration rates were compared between the clay calcined at 700℃ for one hour before HCl leaching and the clay without the calcination. At the filtration temperature of 25℃, the calcination had little effect on the filtration rate. As the temperature was increased to 60℃, however, the calcination gave a higher filtration rate. When the filtration pressure was increased from 1 to 5 atm, the cake resistance increased from 8.1×10¹⁰ to 9.3×10¹⁰ m/kg with the calcined clay and 1.11×10¹² to 6.37×10¹² m/kg with the uncalcined clay, respectively. Under a filtration pressure of 1 atm., the water content of the cake was 1.24 g water/g dry cake with the calcined clay and 1.12g water/g dry cake with the uncalcined clay. Irrespective of whether the clay was calcined or not, 90 to 93% of the aluminum in the mother liquor trapped in the cake could be removed by washing the cake three times with a equal volume of water.

Pressure Filtration Clay Calcination HCl Leaching

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