Write the equations for the Van Arkel method used for the refining of Zirconium, the two tempertures being `=870K` and `~=2070K`.

Explanation

To solve the question regarding the Van Arkel method for refining zirconium, we will outline the steps and provide the corresponding chemical equations at the specified temperatures of 870 K and 2070 K.

### Step-by-Step Solution:

1. **Understanding the Van Arkel Method**:
The Van Arkel method is a process used for refining metals, particularly those that are reactive and have impurities. In this case, we are focusing on zirconium.

2. **First Step (870 K)**:
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