Simple Solutions That Work! Issue 15

26 EXCESSIVE SPLASHING CAUSES OXIDE GROWTH! Recommended Fluxing Procedures The following is a list of steps for flux application: 1. Apply flux to walls by broadcasting or spraying with a flux gun and use the appropriate flux (either A-128, A-130F or Amlox 109). Close door and heat for approx. 15 min. Step 1 is used only if wall flux is needed to remove build up. If not, go to step 3. 2. Open door, preheat scraping tool, scrape walls to remove build up. If build up is heavy, it will need to be taken off in layers with several applications. 3. After scraping walls, broadcast drossing flux over surface of bath (approx. 1/2 lb./1000 lb. of metal) depending on depth of dross layer. 4. Preheat rake and rabble flux thoroughly. 5. Dross layer should turn cherry red. If so, go to step 7. If dross is black, add a small amount of flux and repeat step 4 or turn on high flame for 5-10 min. 6. Rabble flux again. It should have cherry red dross. If dross is white hot, high flame was on too long. If dross is black, turn high flame back on for 5-10 min. 7. Pull dross to charge well. Rabble the dross in well to recover more metal. 8. Skim well, tapping skimmer to release additional metal while removing. 9. Use proper tools for the job. 10. Clean quickly and carefully. 11. Do a thorough job. Circulations Effect on Dross The alloy remains constant throughout the furnace when circulating properly. We recommend 5-7 volume changes an hour. This will keep a uniform temperature in the furnace, which will result in less dross and oxides formed. That’s because there is now no superheating of the surface of the metal. The BTU absorbed into the aluminum are distributed into the flow from the circulation and results in much lower surface temperatures (60-90 degrees F). This is beneficial because: • You save money of metal and refractory relines • It’s easier to clean a clean furnace • You save energy because of the density of hard oxide Auxiliary Equipment Every foundry secondary or die caster that produces dross should consider all the methods of recovering metal from that dross. There are rotary furnaces for large volumes of dross. For medium producers of dross, there are large dross presses that squeeze the aluminum out while it’s still hot and can even pour it back into the furnace while molted, which lowers costs because you don’t have to re-melt the metal. The third method is for smaller dross producers or those that want to do it with portable devices at each furnace. Dross stirrers work very well. This concept allows the furnace tender to place the hot dross in this bowl and apply additional flux, then allow the unit to stir the flux into the dross, which further reacts with the aluminum to remove it from the dross. It doesn’t make sense to pay someone else to get the metal out of your dross when you can recover it yourself. You can even pay for the investment in less than 12 months. There is money to be saved by recovering your own aluminum from the process, reducing scrap, and having cleaner furnaces. This amounts to hundreds of thousands of dollars a year for some foundries, secondaries, and large die casters. Appoint a metal saving guru within your organization to manage the metal you melt and send off for reclamation. This person will pay for themselves many times over. Contact: RICHIE HUMPHREY [email protected]