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| Ribeiro,Fabiana Rodrigues; Egreja Filho,Fernando Barboza; Fabris,José Domingos; Mussel,Wagner da Nova; Novais,Roberto Ferreira. |
| The industrial refining of kaolin involves the removal of iron oxides and hydroxides along with other impurities that cause discoloration of the final product and depreciate its commercial value, particularly undesirable if destined to the paper industry. The chemical leaching in the industrial processing requires treatments with sodium hyposulfite, metallic zinc, or sulfuric and phosphoric acids, in order to reduce, dissolve and remove ferruginous compounds. To mitigate the environmental impact, the acidic effluent from the leaching process must be neutralized, usually with calcium oxide. The resulting solid residue contains phosphorous, zinc, and calcium, among other essential nutrients for plant growth, suggesting its use as a macro and micronutrient... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Industrial residue; Fertilizer; Kaolin refining. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832007000500011 |
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| Soares,Liliane Catone; Egreja Filho,Fernando Barboza; Windmoller,Cláudia Carvalhinho; Yoshida,Maria Irene. |
| Despite the considerable environmental importance of mercury (Hg), given its high toxicity and ability to contaminate large areas via atmospheric deposition, little is known about its activity in soils, especially tropical soils, in comparison with other heavy metals. This lack of information about Hg arises because analytical methods for determination of Hg are more laborious and expensive compared to methods for other heavy metals. The situation is even more precarious regarding speciation of Hg in soils since sequential extraction methods are also inefficient for this metal. The aim of this paper is to present a technique of thermal desorption associated with atomic absorption spectrometry, TDAAS, as an efficient tool for quantitative determination of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metal; Analytical method; Weathered soils. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401100 |
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