Application of compressed air in non-ferrous metal smelting and manufacturing

Non-ferrous metal smelting is to smelt non-ferrous metals from ore and turn them into ingots;

Non-ferrous metal manufacturing is to use non-ferrous metal ingots to be cast into blanks, and then to finish processing, if necessary, to spray treatment, and finally to manufacture industrial products.

1. Smelting of non-ferrous metals

In the smelting workshop of the electrolytic aluminum plant, there are many cranes that require compressed air, and they are generally equipped with screw air compressors. These screw air compressors can be directly installed on the crane because of their small size and light weight. Generally, a crane is equipped with a 3m³/min or 6m³/min air compressor with a pressure requirement of 0.6-0.7MPa, and the quality of the compressed air used is very low. According to the ISO/DP8573/1—88 quality level standard, the quality level of compressed air used in these cranes is generally set as 3-7-4, that is, solid particles: level 3; water content: level 7; oil content: level 4. The air compressor post-processing equipment in this link generally only needs to be equipped with a filter.

In addition to the compressed air used by the crane in the smelter, there is also the gas used for the instrument. The pressure is generally 0.6-0.7MPa. The quality level of the compressed air used is generally set as 2-3 (4)-2, that is, solid particles: Level 2: ; Water content: Level 3 or 4; Oil content: Level 2. The air compressor post-processing equipment in this link generally requires the use of a dryer and a filter.

2. Processing and manufacturing of non-ferrous metals

The processing and manufacturing process of non-ferrous metals is generally divided into three stages: the first stage is blank production; the second stage is finishing; the third stage is appearance spraying.

The first stage: blank production. First, make a mold according to the design drawings, and then melt and smelt the raw materials of non-ferrous metals (such as copper or aluminum, etc.). If necessary, add some metal elements in the specified amount during the smelting process to make it a non-ferrous alloy. After refining, the liquid non-ferrous metal is cast into the mold, and the blank is formed after cooling.

In this series of technological processes, many mechanical actions need compressed air to complete, such as the opening of the smelting furnace door, the lifting, hoisting and casting of the ladle containing liquid non-ferrous metals all need compressed air to complete. The pressure requirement of compressed air is generally 0.6～0.7MPa. The compressed air quality standard used here is not high, and the quality level is generally set as 3-7(6)-4, that is, solid particles: level 3; water content: level 7 or level; oil content: level 4. The air compressor post-processing equipment in this link generally only needs to be equipped with a compressed air filter.

The second stage: finishing. When the blank is finished, it needs to be finished. Finishing is generally carried out on CNC machine tools. The fixtures and tool loading and unloading of these CNC machine tools are all done by the pressure of compressed air.

For a CNC machine tool or machining center, the compressed air consumption is not very large, it may only be about 0.5m3/min. The total consumption depends on the number of processing equipment, and the pressure requirement is 0.6～0.7MPa. The quality requirements are not high, especially the oil content is not high, and the water requirement is that the pressure dew point is 10°C. The quality level of compressed air used by these equipment is generally set as 2-6-3, that is, solid particles: level 2; water content: level 6; oil content: level 3. The post-processing equipment here generally needs to be equipped with a dryer and a filter.

The third stage: appearance spraying. After finishing, the appearance of some parts or finished products needs to be sprayed to make it a real product.

In addition, some instrument air is also needed in these factories. The quality of instrument air is not as high as that of spraying air, and the amount of air used is not large. The compressed air system for spraying can be used directly, and the pressure is usually 0.6-0.7 MPa. According to the previous introduction, and in accordance with the ISO/DP8573/1—88 quality level standard, the quality level of compressed air used in instruments and spraying equipment is generally set as 2-2(3)-1, that is, solid particles: level 2; water content: 2 or 3 grade; oil content: 1 grade. The post-processing equipment here generally needs to be equipped with a compressed air filter to meet the air consumption standard.