The authors have tried to control crystallizing refined sugar, beat sugar, raw sugar, glucose, glucose for medical use, MSG and other chemicals on an industrial basis, and have configuredvarious program control methods using temperature, super saturation, refractive index and Rheometer (Trade name) as growth factor detection elements.
As a result, the Rheometer based intermittent growth control system (IGCR) detected the valueof the embryo, which was a transitional material between the liquid and solid produced in motherliquor during growth, and controls its growth, fissioning and collapse.
This new development has resulted in a remarkable improvement in productivity and qualitycompared with conventional manual and automatic controls. The requirements for crystal growthsuggested that solution super saturation did not indicate crystallization speed, but that it was reallythe embryo value insted.
From this premise, in order to produce good quality salt crystals of different sizes, crystal growingspeed must be controlled, and therefore, it is necessary to detect the salt embryo value.
Therefore, a highly sensitive monel Rheometer has been developed, and as a resultof salt embryovalue measurement using this Rheometer, no change in the indication of the embryo value wasrecognized.
In this report, the method of checking for the presence of the embryo was adopted, since thetwo methods of continuous growth control by level (CGCL) and intermittent growth control bylevel (IGCL) differ in the growth and collapse of the embryo by assuming that the free energylevel indicated by the salt embryo was biased a little toward the solution when compared withsugar, etc. In addition, since crystal growth speed in the continuous crystallizing pan must be fixed, an experimentin embryo growth restriction control was made.As a result, it was confirmed that in comparison with the former, IGCL has a growing speedabout 4 times faster than CGCL, while for the later, the desired crystals (averagegrain size andgrain distribution) were attained.This is necessary to limit the seeds and brine supplied to the pan and changes in dischargedsalt volume.This report describes these experimental processes and the fundamentals of the control system established and actually used at each factory.

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A turbidimetric technique using 2-aminoperimidine was investigated for the determination ofsulfate ion in sea water. This method was simpler in procedures and more accurate in determinationthan the conventional gravimetric method by barium chloride and others.
The calibration curve obtained by the present method was linear for the range of 0to 10 mg/l, showing a satisfactory reproducibility as evidenced by the coefficient of variation of 1.70% foundfor repeated experiments. The coefficient of variation of the analytical results was less than 2.07% in this method.
The sulfate ion concentration in used sea water was found to be 2.66 g/l (sample A) and 2.48g/l (sample B) by the present method, showing a good agreement with the results obtained bythe gravimetric method using barium chloride. As a result of this experiment, it was proved tobe an effective method as being significant for rapid and simple determination of sulfate ion in sea water.

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