Improvement of iron removal from silica sand using ultrasound-assisted oxalic acid

Designing and optimization of separation process of iron impurities from kaolin by oxalic acid in bench-scale stirred-tank reactor

“…Oxalic acid is found to be the most promising organic acid because of its acid strength, good complexing characteristics and high reducing power (Ambikadevi and Lalithambika, 2000). Using oxalic acid, the dissolved iron can be precipitated from the leach solution as iron (II) oxalate dihydrate, which can be represented as a useful potential feedstock for added-value products (Du et al, 2011). Oxalic acid can be produced both by chemical and fermentative processes.…”

“…Several studies have evaluated the kaolin processing by different methods (Guo et al, 2010;Tuncuk et al, 2013;Zegeye et al, 2013) especially with oxalic acid and oxalic acid-producing strains of A. niger, to reduce its iron impurities and increase its quality (De Mesquita et al, 1996;Raghavan et al, 1997;Taxiarchou et al, 1997;Ambikadevi and Lalithambika, 2000;Cameselle et al, 2003;Mulligan et al, 2004;Calderon et al, 2005;González and Ruiz, 2006;Lee et al, 2007;Du et al, 2011;He et al, 2011;Martínez-Luévanos et al, 2011;Xia et al, 2012). In the previous studies (Hosseini et al, 2007;Aghaie et al, 2009), firstly, bioleaching of iron from a highly contaminated kaolin sample using two different strains of A. niger was carried out on laboratory scale and the effects of strain type, pulp density and time of clay addition on the iron removal were investigated by employing a 2 3 full factorial design.…”

Processing of quartz lumps rejected by silicon industry to obtain a raw material for silica glass

“…Several works as Lee et al (2009) and Liu et al (1996), report that the use of HF is the best way to reduce significantly the level of impurities such as Al and Li. However, more recent works [Du et al, 2011 andLi et al, 2010], avoided using HF as it is environmentally harmful and causes undesirable quartz mass losses. In this work we intended to evaluate if the use of HF on the chemical treatment was indeed necessary on the studied material, by comparing it with the results obtained using only HCl on a higher concentration.…”

“…Although there are several processing methods to reduce impurity levels in quartz, the characteristics of the ore are extremely important for obtaining a good processed quartz powder, able to be transformed into high-quality fused silica. Some of the processing methods include acid leaching [Du et al, 2011], electrochemical treatment [Dal Martello et al, 2011], and biological leaching [Arslan et Bayat, 2009]). Studies reveal that some of the impurities, as Al, Li and Ge, are preferentially located in the quartz crystal lattice itself, and not in other minerals present among quartz as inclusions or adsorbed material [Rakov, 2006, Götze, 2009].…”

Improvement the Quality of Egyptian Kaolin for Industrial Applications

“…In addition, the anatase (titaniferrous) and mica can also contain iron contaminants [1]. The presence of such impurities is prohibitive to the production of optical fibers, glass, ceramics and refractory materials, so considerable efforts have been devoted to the problem of removing these contaminants by physical, chemical, or combination between them [3].…”