1. General
This method is adopted by our Testing Department for graphite particle size testing.

2. Equipments

1) Vibrating machine, in accordance with GB 9909

2) Standard sieve, in accordance with GB 6003

3) Oven at working temperature between 105 and 110℃

4) Measuring balance, accurate to 0.01g

5) Stop watch

6) Fur brush

3. Method

1) Weigh about 50g of sample (accurate to 0.01g) with less than 1% moisture, pour into a standard bottom mounted sieve, and sift in the vibrating machine.

2) Sifting time depends on particle size of sample:

       a. 10 minutes for sample size of mainly larger than 75μm (200 mesh);

       b. 20 minutes for sample size of mainly smaller than 75μm (200 mesh), but larger than 45μm (325 mesh);

       3. 30 minutes for sample size of mainly smaller than 45μm (325 mesh).

3) Stop when the required sifting time is up, empty the content underneath the sieve, continue sifting for additional 1-minute periods, repeat until Sifting End Point is reached.  Weigh residue on top of, and the finer particles underneath, the sieve.

Sifting End Point: After finishing the initial sifting time, continue sifting for additional 1-minute periods.  Sifting End Point is reached when the finer particles underneath the sieve weighs less than 0.3% of the residue on top of the sieve.

4) Calculation

x _[1] = m_[1] / m *100%

x _[2] =(1-x _[1])*100%

In the above formula,
　　x _[1]  —— Percentage of residue on top of sieve (%)

　　x _[2]  —— Percentage of finer particles underneath sieve (%)

　　m_[1]  —— Weight of residue on top of sieve (g)

　　m    —— Total weight of sample (g)

5) Allowed Error

Allowed error between results of two parallel tests must be under 2.0% in the same laboratory, and arithmetic average of the two results is the final result.  Otherwise, sample and test again.