The double-chamber rectangular furnace smelts aluminum mainly with scrap aluminum, which is remelted, deslagging, and then cast into aluminum products.

In the smelting process, the most fundamental requirements are: shorten the smelting time as much as possible, accurately control the chemical composition, minimize the melting loss, adopt the best smelting method, and properly control the melting temperature, so as to obtain an alloy melt with high purity and chemical composition. The aluminum melting furnace is a typical periodic high-temperature smelting device, which usually starts from the aluminum ingot entering the furnace to the completion of smelting, and can be divided into the charging period, the melting and heating period, the refining and the insulation period. In the design of the rectangular smelting furnace, on the one hand, the flame should be fully contacted with the surface of the casting to enhance the convection heat transfer, and on the other hand, the heat exchange time between the high-temperature flue gas and the metal should be extended as much as possible to improve the operating efficiency.

The raw material sources of recycled aluminum are complex and there are many types of impurities. In addition to higher requirements for its recovery and separation technology, special recovery and remelting equipment is also required. At present, there are three types of recycled aluminum remelting devices widely used in my country, one is a rotary furnace, one is a side well furnace, and the other is a double-chamber heating furnace. Among them, the side shaft blast furnace is mainly used to process crushed materials and lightweight materials, the rotary furnace is mainly used for aluminum slag and aluminum ash, and the double-chamber melting furnace can process various forms of aluminum slag, which is the most commonly used equipment for recycling aluminum remelting. The double-chamber melting furnace was originally designed for processing extruded waste, but with the advancement of technology, it can now process aluminum ingots of various specifications, including aluminum ingots containing rubber, plastic, paint and oil. The aluminum ingots after separation and pretreatment can be directly sent to the double-chamber furnace for remelting.

According to its structural characteristics, the double-chamber furnace is divided into two parts, the waste chamber and the heating chamber. The aluminum liquid is sent from the heating chamber to the waste chamber through the feeding well by a circulating pump, and the aluminum liquid is used to melt the waste aluminum. The opening direction of the furnace door of the waste chamber and the heating chamber can be flexibly arranged according to the workshop plane. There are two major types of circulating pumps at present, one is a mechanical pump and the other is an electromagnetic pump.

The advantage of the double-chamber melting furnace is that it can treat the aluminum slag containing pollution, and carry out pyrolysis, waste gas combustion, rapid cooling and other processes at high temperature to achieve the standard emission of waste gas. Under high temperature conditions, it is first pre-treated at high temperature, dehumidified, and then pyrolyzed at high temperature to remove surface pollutants. Wet waste cannot be added directly to the aluminum liquid, especially the baling material. The high-temperature reaction mainly proceeds along the thermal bridge, and as the waste is suspended on the surface of the aluminum solution, the pyrolysis continues until the entire waste is immersed in the aluminum solution.

The waste gas containing pollutants generated during the pyrolysis process is introduced into the heating chamber, where it is fully burned and decomposed. By controlling the composition of the furnace gas in the heating chamber, on the one hand, sufficient oxygen can be supplied to the combustion of the combustible waste gas, and the safe and environmentally friendly incineration of the pyrolysis gas can be ensured. On the other hand, the double-chamber furnace can achieve the purpose of energy saving and consumption reduction by burning the combustible waste gas. On this basis, the regenerative burner is used to quickly cool the flue gas to prevent secondary pollution.

The above is the aluminum smelting process of the double-chamber rectangular furnace.