Reduction Method Of Sodium Metabisulfite For Gold

Sodium metabisulfite (Na2S2O5) is a commonly used reducing agent that can be used for the reduction of gold. The method of reducing gold with sodium metabisulfite has attracted much attention due to its simple operation, low cost, and high recovery rate. For the functions of sodium metabisulfite in mining, you can find it in Application And Effect Of Sodium Metabisulfite In Mining.

1. Principle

Sodium metabisulfite reacts with sodium hydroxide (NaOH) or sodium carbonate (Na2CO3) under acidic conditions to generate sulfite ions (SO32-), which have a strong reducing effect. Under the reducing force, gold ions can be reduced to metals. Meanwhile, the product of the reduction reaction sulfate ions and water, and the reaction equation is as follows:

2AuCl4 ^ -+3NaHSO3+3H2O → Au2+3NaHSO4+8HCl

2. Operation steps

2.1 Preparation

Firstly, prepare the necessary drugs and reagents. What is needed is sodium metabisulfite, sodium hydroxide, gold salt, and acid. Among them, sodium hydroxide or sodium carbonate is used to regulate the pH value of the reaction system, while acid is used to maintain the acidity of the reaction system.

2.2 Reaction

Add the required gold salt to acidic conditions and adjust the pH value of the reaction system by adding an appropriate amount of sodium hydroxide or sodium carbonate. Then, an appropriate amount of sodium metabisulfite is added to the reaction system, stirred evenly with a glass rod, and after the complete reaction, the product is poured out. After treatment, pure metal can be obtained.

3. Advantages and disadvantages

The method of reducing gold with sodium metabisulfite has the following advantages:

(1) Easy to operate without the need for advanced technology.

(2) Low cost, with a wide range of drugs and reagents.

(3) High recovery rate allows for the production of high-quality pure metals.

There are also some drawbacks:

(1) The reaction speed is slow and requires a long reaction time.

(2) Toxic gases may be generated during operation, and protection measures should be taken.

(3) After recycling, subsequent processing is required, which is a complex process.

4. Precautions

When conducting experiments on the reduction of gold with sodium metabisulfite, the following points need to be noted:

(1) Wear protective gloves, masks, and other safety measures during operation.

(2)Drugs,reagents, and equipment should be used under laboratory management standards.

(3) During the operation, there must be no ignition or smoking behavior.

(4) The treatment of products needs to comply with environmental regulations.

In summary, the method of reducing gold with sodium metabisulfite has the advantages of simplicity, low cost, and high recovery rate, thus it has been widely used in metal recovery and purification.