Fraunhofer-Gesellschaft

Publica

Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Verfahren zur magnetischen Abtrennung von Fällungsprodukten aus Fluiden mit Hilfe von wiederverwendbaren, superparamagnetischen Kompositpartikeln

METHOD FOR MAGNETIC SEPARATION OF PRECIPITATION PRODUCTS FROM FLUIDS USING REUSABLE SUPERPARAMAGNETIC COMPOSITE PARTICLES
 
: Mandel, Karl Sebastian; Hutter, Frank; Gellermann, Carsten

:
Frontpage ()

DE 102012212955 A1: 20120724
German
Patent, Electronic Publication
Fraunhofer ISC ()

Abstract
The invention relates to a method for treating an aqueous fluid, comprising the following steps: (a) adding magnetically separable particles to the aqueous fluid, each of these particles comprising a plurality of nanoparticles with reversible magnetic properties and a matrix which has an inorganic portion between 70 and 100 wt.% relative to the matrix weight, 80 to 100 wt.% of the inorganic portion of the matrix consisting of SiO2, wherein i. the particles have an average diameter in at least one direction of at least 5 [mu]m, ii. the particles have a surface (according to BET measurement) of at least 1 m2/g and a (cumulative) pore volume of less than 0.195 cm3/g (ml/g), iii. a loss of material from the nanoparticles with reversible magnetic properties of less than 2 wt.% occurs after 12 hours of stirring of the magnetically separable particles in acid and alkali solutions with a pH value of and of 12, (c) allowing the particles to act upon the aqueous fluid until precipitated materials or materials floating in the fluid adhere thereto, (d) separating magnetically separable particles with materials adhering thereto from the aqueous fluid with the aid of a magnetic field gradient. In particular, the method also includes (b) adding a precipitant to the fluid, which is able to precipitate desired dissolved materials therein, with the proviso that the steps (a) and (b) can be carried out in any sequence, or that the precipitant is flocculated onto the magnetically separable particles and these are then added to the aqueous fluid. The separated particles can be freed of the flocculation with the aid of, for example, acid and be reused. The materials accumulated in the acid can be recovered or - possibly after processing - be deposited.

: http://publica.fraunhofer.de/documents/N-310974.html