Synthesis of Calcium Aluminates from Non-Saline Aluminum Dross

Abstract

The present work examines the synthesis of tricalcium aluminate (for use as a synthetic slag) from the non-saline dross produced in the manufacture of metallic aluminum in holding furnaces. Three types of input drosses were used with Al2O3 contents ranging from 58 to 82 wt %. Calcium aluminates were formed via the mechanical activation (reactive milling) of different mixtures of dross and calcium carbonate, sintering at 1300 °C. The variables affecting the process, especially the milling time and the Al2O3/CaO molar ratio, were studied. The final products were examined via X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The reactive milling time used was 5 h in a ball mill, for a ball/dross mass ratio of 6.5. For a molar relationship of 1:3 (Al2O3/CaO), sintered products with calcium aluminate contents of over 90% were obtained, in which tricalcium aluminate (C3A) was the majority compound (87%), followed by C12A7 (5%).

Maximize the use of municipal waste generated by the hydrogen peroxide industry in the production of high-quality refractory CAC

“…2 ). The dominance of the C 3 A phase over the mayenite phase in the case of CA40 and CA50 mixes may return to the observed increase of CaO wt% compared to the Al 2 O 3 content in these two mixtures 26 . At 1450 °C, CA40 and CA50 mixes were fully melted, while CA60 and CA70 mixes survived due to their high alumina content.…”

Effects of Different CaO/Al2O3 Ratios on the Phase Composition and Desulfurization Ability of CaO-Based Desulfurizers in Hot Metal

“…Aluminum will react with water, resulting in ammonia (NH 3 ), flammable gases (hydrogen (H 2 ), and methane (CH 4 )) [20,21], thereby causing stinky burning and serious harm to groundwater and ecosystems [22][23][24]. According to the studies of C. Y. Lin, F. H. Lu, and Z. Su et al [25,26], the AlN in AD will transfer to Al 2 O 3 when the temperature is higher than 1000 • C. Hence, many studies have investigated sintered calcium aluminate from aluminum dross [26][27][28]. Z. Su et al revealed that a 1.7 molar ratio of Ca/Al roasting for 120 min at 1400 • C under ambient atmosphere would result in high-purity dodecacalcium heptaaluminate (C 12 A 7 ) [26].…”

“…Hu et al showed that mixing CaO and secondary aluminum dross in a 0.6:1 (mass ratio) solution resulted in premelted calcium aluminate slag after calcinated at 1723 K for 2 h [27]. F. A. López et al noted that using CaCO 3 and aluminum dross as sources for a 1:3 molar ratio of Ca/Al mixture and sintering at 1300 • C would result in two kinds of calcium aluminate, tricalcium aluminate (C 3 A) and C 12 A 7 [28]. Using aluminum dross in steel melting will benefit two methods.…”

Waste to Wealth Strategy: Preparation and Properties of Lightweight Al2O3-SiO2-Rich Castables Using Aluminum Dross Waste

“…Meanwhile, some ceramics, refractories, and glasses were successfully prepared based on the chemical compositions of ADW. López et al [16] synthesized calcium alu-minates from the non-saline dross produced during manufacturing metallic aluminum in holding furnaces. Romero et al [17] sintered glass-ceramic tiles by the sinter-crystallization of mixtures composed of aluminum slag and reclaimed packaging glass.…”