Ground test sample to grain size of 0.85mm or smaller and apply heat to them, uniformly mixed, for 2-hr at 150~170 and then uniformly spread 0.5~1g of them onto the bottom of a weighting bottle (weight W) and close the lid and cool it down to room temperature in a desiccator.

Check the weight and mark it as W + W. Prepare three glass bottles filled with different amount of sulfur solution defined in Table 2 to maintain relative humidity 20%, 50%, and 90% defined in Korean Industrial Standard (KS A 2110 : Table 1).

Open the lid and insert the test sample and maintain each bottle at 25~30 for 48-hr, and then take the sample out and close the lid immediately to check the weight and mark it as W+ W. Calculate moisture absorption rate based on the following equation.
   
 
 
Table1) Absorption test
relative humidity (%)
an aqueous solution sulfate
weight (%)
specific weight (20/4)
20 %
58.6
1.433
50 %
43.1
1.330
90 %
16.0
1.109
 
Table2) Quality
Quality item
Unit
Quality
A-type
B-type
class1
class2
class1
class2
moisture absorption rate
at relative humidity 20%
%
8.0 over
3.0 over
moisture absorption rate
at relative humidity 50%
20.0 over
10.0 over
moisture absorption rate
at relative humidity 90%
30.0 over
50.0 over
moisture content rate
%
2.0 below
pH
-
4 - 8
specific resistance
cm
3000 over
ingredient
%
anhydrous pileus over 98 over
 
Check the weight of 0.5~1g of sample in a specific weighting bottle (weight W) and mark it as W+ W and put it into a desiccator at 150~170 and cool it down to room temperature in a desiccator. Check the weight again and mark it as W + W. Calculate moisture content rate based on the following equation.
   
 
Put 1g of test sample into 100cc hard glass beaker and add 20cc of diluted water. Cover the beaker with watch glass and apply heat for 30 min. to 80 and filter the solution and measure pH for filtered solution.
 
Put 50g of test sample into 400~500cc beaker and add 200cc of hot water (80) and stir the solution from time to time for 30 min. Filter the solution and evaporate the filtered solution and dry the rest at 105 and check the weight. Compare this to the initial sample weight and express the amount of water soluble material in weight ratio (%).
 
   
   
   
 
  Table 3) Coefficients according to expected external conditions
 
temperature humidity
where packaged freight is located
K
Level of external humidit
Heavily High temperature
and high humidity
12
average temperature 30~40,
average humidity ~90%
Reasonably High temperature
and high humidity
20
average temperature 35,
average humidity ~90%
Relatively High temperature
and high humidity
30
average temperature 25,
average humidity ~80%
Medium temp. and humidity
60
average temperature 20,
average humidity < 70%
 
 
 
 
 
 
 
Untitled Document
 
 
Untitled Document