title: Germanium recovery from gasification fly ash: evaluation of end-products obtained by precipitation methods.
abstract: In this study the purity of the germanium end-products obtained by two different precipitation methods carried out on germanium-bearing solutions was evaluated as a last step of a hydrometallurgy process for the recovery of this valuable element from the Puertollano Integrated Gasification Combined Cycle (IGCC) fly ash. Since H(2)S is produced as a by-product in the gas cleaning system of the Puertollano IGCC plant, precipitation of germanium as GeS(2) was tested by sulfiding the Ge-bearing solutions. The technological and hazardous issues that surround H(2)S handling conducted to investigate a novel precipitation procedure: precipitation as an organic complex by adding 1,2-dihydroxy benzene pyrocatechol (CAT) and cetyltrimethylammonium bromide (CTAB) to the Ge-bearing solutions. Relatively high purity Ge end-products (90 and 93% hexagonal-GeO(2) purity, respectively) were obtained by precipitating Ge from enriched solutions, as GeS(2) sulfiding the solutions with H(2)S, or as organic complex with CAT/CTAB mixtures and subsequent roasting of the precipitates. Both methods showed high efficiency (>99%) to precipitate selectively Ge using a single precipitation stage from germanium-bearing solutions.
authors.affiliation: Escuela Superior de Ingenieros de Sevilla, Departamento de Ingeniería Química y Ambiental, Camino de los Descubrimientos, s/n. Isla de la Cartuja, Seville, Spain. fatimarroyo@esi.us.es
authors.forename: Fátima
authors.initials: F
authors.lastname: Arroyo
authors.forename: Oriol
authors.initials: O
authors.lastname: Font
authors.forename: Constantino
authors.initials: C
authors.lastname: Fernández-Pereira
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
authors.forename: Roberto
authors.initials: R
authors.lastname: Juan
authors.forename: Carmen
authors.initials: C
authors.lastname: Ruiz
authors.forename: Pilar
authors.initials: P
authors.lastname: Coca
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002396:Catechols / Q000737:chemistry; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D011232:Chemical Precipitation; D060729:Coal Ash; D003247:Conservation of Natural Resources / Q000379:methods*; D005857:Germanium / Q000302:isolation & purification*; D006862:Hydrogen Sulfide / Q000737:chemistry; D007220:Industrial Waste; D008669:Metallurgy; D052638:Particulate Matter / Q000737:chemistry*; D012996:Solutions
chemical_list: D002396:Catechols; D002593:Cetrimonium Compounds; D060729:Coal Ash; D007220:Industrial Waste; D052638:Particulate Matter; D012996:Solutions; D005857:Germanium; D002244:Carbon; D006862:Hydrogen Sulfide; D000077286:Cetrimonium