A process for the magnetic separation of precipitated material from fluids with the aid of reusable, superparamagnetic compost particles

摘要

The invention relates to a method for the treatment of an aqueous fluid, comprising the steps of:(a) addition of magnetically separable particles to the aqueous fluid, wherein each of these particles, a plurality of nanoparticles with reversible magnetic properties and a matrix, which comprises an inorganic proportion of between 70 and 100% by weight, based on the matrix-weight, respectively, wherein the inorganic portion of the matrix to 80 to 100% by weight of sio₂ .i. the particles have an average diameter in at least one direction of at least 5 µm,ii. the particles having 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) have,iii. a loss of material from the nanoparticles with reversible magnetic properties of less than 2gew.-% at 12 - hours stirring of the magnetic particles, which can be detached in acidic and alkaline solutions with a ph value of 1 and of 12,(c) subjecting the particles on the aqueous fluid, to precipitated or in the fluid adhere to the floating substances,(d) separating particles with a separable magnetically adhering thereto substances from the aqueous fluid with the aid of a magnetic-field.In particular, the process comprises in this case, moreover, (b) the addition of a precipitating agent to the fluid, which is capable of taking up the desired dissolved substances precipitate therein, with the proviso that the steps (a) and (b) can be carried out in any desired sequence, or that the precipitating agent to the magnetically separable particles is flocculated and these can then be added to the aqueous fluid. The separated particles, with the aid of, for example, acid freed from the flocculation and be reused. The substances may be enriched in the acid is recovered, or, if appropriate, after working up – be dumped.