Which of the following options are correct?

Options

A. Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast
B. In extraction of silver, silver is extacted as cationic complex
C. Nickel is purified by zone refining
D. Zr and Ti are prified by van Arkel method

Explanation

To determine which of the provided options are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Option A: Cast iron is obtained by remelting pig iron and scrap iron and coke using hot air blast.**
- **Analysis**: This statement is correct. Cast iron is indeed produced by remelting pig iron along with scrap iron and coke, typically in a blast furnace. The process involves the addition of carbon and other elements, resulting in a material that is harder and more brittle than pig iron.
- **Conclusion**: **Correct**

2. **Option B: In extraction of silver, silver is extracted as cationic complex.**
- **Analysis**: This statement is incorrect. In the extraction of silver, silver is typically extracted as an anionic complex, not a cationic one. Therefore, this statement does not hold true.
- **Conclusion**: **Incorrect**

3. **Option C: Nickel is purified by zone refining.**
- **Analysis**: This statement is also incorrect. Nickel is primarily purified using vapor phase refining methods, such as the Mond process, rather than zone refining.
- **Conclusion**: **Incorrect**

4. **Option D: Zr and Ti are purified by van method.**
- **Analysis**: This statement is correct. Zirconium (Zr) and Titanium (Ti) are purified using the Van Arkel method, which involves the formation of volatile iodides that can be decomposed to yield pure metals.
- **Conclusion**: **Correct**

### Final Answer:
The correct options are **A** and **D**.