I. Making Crystallizer Solution
First decide what temperature is desired to start crystal growth. For schools,
a starting temperature between 40 C and 50 C is probably desirable to lower any risk
of a student burning themselves.
Use the Solubility Data Table. Check what the solubility in grams KDP/ gram solvent
is at the chosen temperature. Use that figure along with the weight of solution desired
to calculate how much KDP salt should be added to how much water. (The weight of
solution should be approximately 1000 g above the desired weight of solution in the
crystallizer tank).
Weigh out the appropriate amount of KDP salt in a large beaker. Add it to a large
round bottom flask (with the help of a funnel and stirring rod). Add the weighed-
out portion of water and heat the solution, stirring occasionally, until all the
salt is dissolved.
The solution will be filtered into the crystallizer tank where it will continue to
filter for 3 - 24 hours. It will then be overheated for 24 hours before it is ready
for use. (Overheat temperature should be at least 20 C higher than the saturation
temperature, typically 60-70 C).
|
