Energy-saving technology and measures for foundry produ […]
Energy-saving technology and measures for foundry production
The foundry industry is a major energy consumer in the machinery industry. High energy consumption, low energy utilization, serious pollution, and poor economic benefits restrict the development of the foundry industry. Reasonable use of energy and vigorous efforts to save energy is an important task of the foundry industry.
Energy-saving technology and energy-saving measures include the following aspects.
1. Old sand recycling and reuse
In the industrialized countries of Europe and the United States, the reuse of used sand has always been a major research topic, and good research results have been obtained, and it has been put into industrial production. When casting non-ferrous metal parts, iron castings and steel castings. According to the sintering temperature of the old sand, the old sand is regenerated mechanically. The regeneration rate is roughly 90%, 80% and 70%, respectively. The combination of old sand recycling and wet regeneration is the most economical and ideal choice. The two-stage wet regeneration removal rate (Na2O) can reach 85%-95%, and the single-stage can also reach 70%. 90% of the old sand is recycled and reused, and the quality is close to that of new sand. The British company uses thermal regeneration, which can increase the regeneration rate by about 10% to 20%. Moreover, the cost recovery period of the thermal process used sand recycling equipment is relatively short, and the cost can be recovered after two years of operation. After the recovered zirconium sand that cannot be regenerated by mechanical method is treated by thermal method, the quality of the reclaimed sand is better than that of new sand. In the United States, the annual consumption of sand used in the foundry industry is about 5 million tons. BastianKC and AllemanJE have found that the used sand after foundry is used as a highway roadbed material. It can fully meet the performance requirements of materials used in highway construction. Its performance is also better than that of new sand of the same species.
2. Recycling of binder
Environmentally friendly sand core inorganic binder and sand treatment and regeneration technology have received more and more attention. A company’s Beach-BoX inorganic binder is a fluid containing a variety of minerals. The core sand uses 95% sand and 5% binder. For example, if the casting is dry-processed, the binder remains in the sand for activation. The binder can be reused many times without adding new binder as long as 2.5% of water is added, which means that the maximum amount of binder added per batch in production is only 1.6% by removing water. It causes the chemical reaction of the binder component to harden. The usable time is unlimited, but the relative humidity should not exceed 70%. The mixed sand can be stored for a long time if it is sealed. FoundryAutomation and MEG's binders are in powder form. They are used in aluminum alloy cores, storage and pouring, and they do not generate gas, and there are no environmental problems that may be caused by resin-based binders. 85% of the water from wet sand cleaning can be reused, and 100% of the recovered materials can be reused.
3. The regeneration of molds and mold materials
Since the 1990s, the U.S. and European countries have treated mold materials or recycled mold materials discarded by precision casting manufacturers through special purification treatments, and then adjusted the composition according to different needs of users to form "recycled-recycled mold materials". The key to the technology is to use advanced multi-stage filtration or centrifugal separation to speed up the operation process and obtain a purer mold material. MittererC discovered in research on aluminum casting molds. Coating a hard film on the surface of the steel mold can effectively inhibit corrosion, use the protective effect of nitrogen and carbides to improve the resistance to thermal cracking, corrosion and other damage behaviors, and replace the thick oxygen-based coating material with a thin film. Thereby effectively extending the life cycle of the casting mold. Its core technology is PACVD technology, namely plasma chemical vapor deposition.
4. Energy-saving technology centered on smelting
The energy consumption of the smelting part of castings accounts for about 50% of the total energy consumption of castings, and the casting waste caused by smelting accounts for about 50% of the total waste. Therefore, the use of advanced and applicable smelting equipment and smelting process is the main measure of energy saving.