Which of the following statements are correct ?

Options

A. A depressant prevents certain type of particle to come to the froth.
B. Copper matte contains `Cu_(2)S` and `ZnS`
C. The solidified copper obtained from reverberatory furnance has blistered appearance due to evolution of `SO_(2)` during the extraction.
D. Zinc can be extracted by self-reduction.

Explanation

To determine which statements are correct, we will analyze each statement one by one based on the principles of metallurgy and the extraction processes involved.

### Step-by-Step Solution:

1. **Statement 1: "A dispersant prevents certain types of particles from coming to the throat."**
- This statement is related to the froth flotation method used for the concentration of ores. In this method, a dispersant is indeed used to selectively separate hydrophobic (ore) particles from hydrophilic (gangue) particles. The ore particles attach to air bubbles and rise to the surface, while the gangue remains in the water below.
- **Conclusion:** This statement is **correct**.

2. **Statement 2: "Copper matte contains CuS and ZnS."**
- Copper matte is produced during the smelting of copper ores, specifically from copper pyrite (CuFeS2). The primary components of copper matte are Cu2S (copper(I) sulfide) and FeS (iron(II) sulfide). Zinc sulfide (ZnS) is not a component of copper matte; it is a separate mineral and is not present in the copper smelting process.
- **Conclusion:** This statement is **incorrect**.

3. **Statement 3: "The solidified copper of the primary furnace has a blistered appearance due to the evolution of SO2 during the extraction."**
- During the extraction of copper, particularly in the smelting process, sulfur dioxide (SO2) is indeed released. The blistered appearance of the solidified copper is due to the gas bubbles of SO2 that escape as the copper solidifies. This is a characteristic feature of blister copper.
- **Conclusion:** This statement is **correct**.

4. **Statement 4: "Zinc can be extracted by self-reduction."**
- Zinc is typically extracted from its ores (like zinc blende, ZnS) through processes such as roasting followed by reduction with carbon or through hydrometallurgical methods. Self-reduction is not a method used for extracting zinc. Instead, zinc sulfide is usually roasted to form zinc oxide, which is then reduced.
- **Conclusion:** This statement is **incorrect**.

### Final Evaluation:
- **Correct Statements:** 1 and 3
- **Incorrect Statements:** 2 and 4