Research of process factors increasing metal yield during aluminum waste remelting

The article presents the results of research determining the most effective technologies for increasing metal yield in the processing of aluminum-containing waste. In particular, peculiarities of the processes of melting aluminum alloys were analyzed using complex methods of furnace and off-furnace processing of charge material containing an increased amount of shovelling scrap and swarf. Studies on the impact of charge preparation and aluminum remelting technology were carried out in SAT-0,16 and IAT-0,4 furnaces on the АК12М2 alloy. Experiments proved that batchwise loading 20 kg of swarf briquette preheated to 300–400 °C into the SAT-0,16 furnace with the addition of flux (composition: NaCl – 50 %; KCl –35 %, Na3AlF6 – 15 %) in the amount of 3 % of total metal mass is the most efficient technology. This technology makes it possible to achieve a metal yield of about 94 %. The study of the remelting technology influence on IAT-0,4 furnace metal yield showed that the greatest effect can be obtained in case of furnace charge (95 kg swarf briquette) by batches of 2 kg into the 7 kg liquid bath with modifier flux (composition: NaCl – 62 %; KCl – 13 %, NaF – 25 %) added in the amount of 2 % from the total metal mass. This technology provides up to 93.5 % of metal yield. Data from 10 series of 5–9 melts were also analyzed with the comparison of metal yield results depending on the mass of briquetted swarf charged into the furnace. A histogram of the change in the porosity of AK12M2 and AK9 samples depending on the content of swarf in the charge (from 0 to 45 %) during remelting. It was found that an increase in the content of swarf in the charge, all other things being equal, leads to an increase in the average porosity score, which indicates the need for additional refining of such melts.

1. Consumption of aluminum, basic consumers’ — Aluminum association. http://www.aluminas.ru/aluminum/in_the_world/ (accessed: 15.07.2020) (In Russ.).

2. Deev V.B., Ponomareva K.V., Kutsenko A.I., Prikhodko O.G., Smetanyuk S.V. The influence of the conditions of melting of aluminum alloys on the properties and quality of castings obtained by gasified models. Izvestiya vuzov. Tsvetnaya metallurgiya (Izvestiya. Non Ferrous Metallurgy). 2017. No. 4. Р. 39—45 (In Russ.).

3. Nappi C. The global aluminum industry 40 years from 1972. World Aluminum. 2013. Р. 1—27.

4. Velasco E., Proulx J. Metal quality of secondary alloys for Al castings. Light Metals (The Minerals, Metals & Materials Society). 2006. P. 721—724.

5. Gesing R., Wolanski М. Recycling light metals from end-of-life vehicles. JOM. 2001. Vol. 53. P. 21—23.

6. Waite P. A technical perspective on molten aluminum processing. Light Metals. 2002. P. 841—847.

7. Leonard S. Aubrey, Dawid D. Smith, Luiz C.B. Martins. New product developments for aluminum cast houses. In: Aluminum cast house technology: Mater. 7-th Australian Asia Pacific Conf. (Australia, Hobart, 23—26 Sept. 2001). Warrendale: TMS, 2001. P. 23—43.

8. Neff D., Sigworth G., Gallo R. Melting and melt treatment of aluminum аlloys. Aluminum Sci. Technol. 2018. Vol. 2A. P. 143—164.

9. Ji-min Wang, Peng Xu, Hong-jie Yan, Jie-min Zhou, Shixuan Li, Guang-chen Gui, Wen-ke Li. Burner effects on melting process of regenerative aluminum melting furnace. Trans. Nonfer. Met. Soc. China. 2013. Vol. 23. No. 10. P. 3125—3136.

10. Nieckele A., Naccache M.F., Gomes S.P., Joao N.E. Combustion performance of an aluminum melting furnace operating with natural gas and liquid fuel. J. Brazil. Soc. Mech. Sci. Eng. 2010. Vol. 32. No. 4. P. 275—283.

11. Anyalebechi P.N. Critical review of reports values of hydrogen diffusion in solid and liquid aluminum and its alloys. Light Metals (The Minerals, Metals & Materials Society). 2003. P. 857—872.

12. Belov N.A., Alabin A.N. Energy efficient technology for Al—Cu—Mn—Zr sheet alloys. Mater. Sci. Forum. 2013. No. 765. P. 13—17.

13. Gavrilin I.V. Remelting aluminum shavings in foundries. Liteinoe proizvodstvo.1998. No. 8. Р. 7—9 (In Russ.).

14. Casatti R., Vedani M. Metal matrix composites reinforced by nano-particles: A review. Metals. 2014. Vol. 4. P. 65—83.

15. Badowsky M., Droste W. Hydrogen measurement practices in liquid aluminum at low hydrogen levels. Light Metals (The Minerals, Metals & Materials Society). 2009. P. 701—706.

16. Calvo-Dahlborg M. Structure of molten Al and eutectic Al—Si-alloy studied by neutron diffraction. J. Non-Cryst. Solids. 2013. Vol. 361. P. 63—69.

17. David H. DeYoung. Salt fluxes for alkali and alkaline earth element removal from molten. In: Aluminum cast house technology: Mater. 7-th Australian Asia Pacific Conf. (Australia, Hobart, 23—26 Sept. 2001). Warrendale: TMS, 2001. P. 99—113.

18. Grachev A.N., Leushin I.O., Leushina L.I. Scheme of the use of industrial waste in foundries. Liteinoe proizvodstvo. 2016. No. 8. Р. 34—37 (In Russ.).

19. Bel S., Davis B., Javaid A., Essadiqi E. Final report on refining technologies of aluminum. Report No. 2003- 21(CF). Canada, 2003. P. 1—3.

20. Velasco E., Nino J. Recycling of aluminium scrap for secondary Al—Si alloys. Waste Manag. Res. 2011. Vol. 29. No. 7. P. 686—693.

21. Yongxiang Yang, Yanping Xiao, Bo Zhou, Markus A. Reuter. Aluminium recycling scrap melting and process simulation. In: Sustainable developments in metals processing: Proc. John Floyd Int. Symp. (Australia, Melbourne, 3—6 July 2005). Carlton: AusIMM, 2005. P. 150—160.

22. Lyutova O.V., Volchok I.P. Welding characteristics of secondary aluminum alloys. Lit’e i metallurgiya. 2013. No. 4. P. 45—50 (In Russ.).