The Fundamental Kinetic Characteristics of Aqueous Dissolution of Chloride and Fluoride Salts from Secondary Aluminium Dross

Abstract

The salt content in the secondary dross obtained beside the recovered aluminium by the hot processing of the primary melting dross hinders further utilization of this material. Secondary dross samples obtained from the industrial hot processing of the primary dross generated by the melting of aluminium alloy scrap were leached with water at room temperature with different Liquid/Solid (L:S) ratios. Vessel filling (the relative volume occupied by the sludge) in the shaking bottles required further consideration in the interpretation of the results. Samples taken regularly within 15 minutes during vigorous shaking showed that NaCl and KCl can be dissolved almost instantly, and completely irrespective of the parameter settings. However, the fluoride additive (CaF2) has a complex behaviour. The results suggest its relation to some side reactions indicating also the conditions of the hot process producing the examined material. The results suggest that the salt content of the secondary aluminium dross can be lixiviated within a 2 -4 minutes virtually completely, but the L:S ratio and the a vessel filling have to be coordinated. At the lowest L:S ratio examined of 1.0, a vessel filling of max. 11% should be observed to achieve this fast salt dissolution. The same dissolution rate can be reached with double the vessel filling (i.e. smaller unit) if the L:S is also increased in this ratio.

Waste-to-Reuse Foam Glasses Produced from Soda-Lime-Silicate Glass, Cathode Ray Tube Glass, and Aluminium Dross

“…The raw materials used to produce foam glass in this work were container glass, CRT glass (provided by Daniella Ipari Park Ltd., Debrecen, Hungary), and secondary aluminium slag (produced by Arconic-Köfém Mill Products Hungary Ltd., Szekesfehervar, Hungary). The metal and salt content of the as-received dross was removed by Kekesi et al [5] with the following method. After melting the aluminum slag to recover the molten metals, the remaining dross was crushed, milled, and washed three times with distilled water to dissolve and eliminate the salt content.…”

“…Since as-received dross contains hazardous components, it must be treated (leached with acid or alkali followed by water washing) prior to use [1,2]. Treated aluminium dross basically contains alumina (Al 2 O 3 ), spinel (MgO•Al 2 O 3 ), salt residues (NaCl, KCl, CaF 2 ), nitride (AlN), and small amounts of fluorides, chlorides, and other components (e.g., MgF 2 , NaAlCl 4 , KAlCl 4 , MgO, KMgF 3 , SiO 2 , Fe 2 O 3 , Al 4 C 3 , Na 2 O, K 2 NaAlF 6 ) [3][4][5][6][7]. The main problem with deposing the residual aluminium dross is the high reactivity with water and air humidity leading to the formation of hazardous and explosive gases, such as NH 3 , CH 4 , PH 3 , H 2 , and H 2 S [6].…”

Alumíniumolvasztási maradék salakok sótartalmának hatékony eltávolítása

“…mindenképpen szükséges. A keletkező por frakcióból a kloridos sók már szobahőmérsékleten is igen jól kioldhatók vízzel[6]. A finom porból történő vizes kioldás ugyan könnyen kivitelezhetőnek hangzik, azonban fontos a sótartalom minél teljesebb eltávolítását minimális oldószerigény és műveleti idő mellett elérni, hiszen a kristályos só kinyeréséhez szükséges bepárlás energiaigénye a gazdaságosságot jelentősen befolyásolja.…”