Processing Technogenic Raw Materials-Phosphorus Slags with the Production of Precipitated Nanosilica and Simultaneous Recovery of Valuable Components

The paper provides a flow sheet of the phosphorus slag processing to produce precipitated silica (white soot). The process conditions for opening phosphorus slag at the I stage of leaching have been selected: the nitric acid concentration is 3.5 mol/dm3; the ratio S:L = 1:3.5; the temperature is 60 oС; and the process duration is 1 hour. The parameters of the white soot production II stage have been determined: the HNO3 concentration is 6.5 mol/dm3; the ratio S:L = 1:3.5; the temperature is 50 oС; and the process duration is 1 hour. The temperature effect on the white soot structure and the specific surface have been established. At optimal process parameters, the white soot batches have been obtained with the main SiO2 component content of 88.2 and 90.5 %, and a specific surface of 170 and 182 m2/g, respectively. The through recovery of silicon into a commercial product is 98.0 % of its initial content in slag.

Comprehensive Processing Technology Of Slags Of Phosphorus Industry To Produce Precipitated Silica And Rare-Earth Concentrate

<p class="TTPSectionHeading">The report presents a technological scheme of complex processing of man-made waste of phosphorus production - slag to produce highly dispersed silicon dioxide and a rare-earth metal concentrate. The technological parameters of each operation of the technology are chosen. Recovery of <span>rare-earth metals</span> from phosphorus slags during various operations was, %: leaching – 95.0; extraction - 90.2; stripping on the average ~ 93.2; the production of ∑ REM oxide concentrate is 93.9. The composition of some batches of "white soot" obtained during processing of the technological scheme is shown.</p>