What is smelting: a pyrometallurgical process in which metal materials and other auxiliary materials are melted and quenched in a heating furnace, and the furnace materials undergo certain physical and chemical changes in the high-temperature furnace, producing crude metals or metal concentrates and slag.

In addition to new and recycled materials, it is sometimes necessary to add fluxes that make the furnace material easy to melt, as well as reducing agents added for certain reactions.

Common melting process characteristics and operating points of copper and copper alloys:

Characteristics and operating points of brass smelting process:

1. Zinc has excellent degassing and deoxidation properties. The purpose of adding deoxidizer phosphorus copper during operation is mainly to improve the fluidity of the alloy;

2. Brass containing more than 20% zinc can generally be produced based on the number of flame discharges;

3. Try to add zinc at low temperatures and remove slag at high temperatures to reduce melting losses;

4. The amount of flux added is about 0.1-0.5% of the weight of the furnace charge;

5. Iron is added as a Cu Fe intermediate alloy, and easily oxidizable elements such as arsenic, magnesium, etc. are added as intermediate alloys with copper.

Characteristics and operating points of bronze smelting process:

1. Bronze should be melted using a medium frequency induction furnace with silicon sand or magnesium sand lining, but when melting aluminum bronze using a core induction furnace, it is best to use neutral or alkaline lining;

2. Silicon bronze and tin zinc lead bronze have strong gas absorption properties, and calcined charcoal should be used as a covering agent. After loading, sufficient charcoal should be added immediately until the casting is completed and no more charcoal should be added to the furnace.

Characteristics and operating points of white copper smelting process:

1. White copper should be melted using a power frequency or medium frequency induction furnace, with silicon sand or magnesium sand lining;

To improve the thermoplasticity of ordinary white copper, titanium and zirconium can be added as modifiers.

When loading, if there is too little residual copper water in the furnace and nickel and iron are not easy to melt, it is allowed to add a small amount of copper first to accelerate melting.

When adding magnesium for deoxidation, magnesium is made of magnesium copper intermediate alloy, as shown in the picture

Methods to reduce smelting losses during the smelting process of copper and copper alloys:

1. Choose a furnace with a small melt pool area for melting. If a power frequency furnace is used instead of a reflector furnace.

2. Develop reasonable operating procedures. Alloy elements that are prone to oxidation and volatilization should be made into intermediate alloys and added at the end, or melted under the cover of flux. When loading materials, it is necessary to achieve a reasonable distribution of furnace materials, and try to use high temperature and rapid melting to shorten the melting time. Low temperature zinc addition is used when melting brass.

3. Scattered materials should be bundled or clumped for use.

4. Correctly control the furnace temperature. Select an appropriate melting temperature while ensuring the fluidity of the molten metal and other process requirements.

5. Generally, it is better to control the micro oxidizing atmosphere in the furnace gas;

6. Choosing a covering agent can prevent metal oxidation and reduce volatilization losses. Alloys containing elements such as aluminum and beryllium generally do not require the addition of a covering agent as they can form a dense oxide film on the surface of the molten metal; However, care should be taken not to damage the oxide film during operation;

7. Correctly select covering agents or fluxes to have sufficient fluidity and covering ability, while taking measures such as high-temperature slag scraping and slag removal to reduce metal loss in the slag.

8. Use deoxidizers to reduce the oxides of the base metal.

9. Using vacuum melting or protective gas melting

Article source: Internet

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