Novel eco-friendly low cost and energy efficient synthesis of (Nd–Pr–Dy)2Fe14B magnetic powder from monazite concentrate

Syntheses of Nd2Fe14B magnetic powder by conventional method is a complicated multi-step process, which produces harmful pollutants and consumes a huge amount of energy and resources. Herein we report a simple chemical route for the preparation of (Nd–Pr)2Fe14B magnetic powder using monazite concentrate as a precursor. Th, U, Sm, and La impurities were removed from monazite leachate by roasting, solvent extraction and leaching the concentrate. Purified leachate consisting of Nd and Pr Chlorides was added to the FeCl3 solution, and the solution produced was co-precipitated with NaOH. RE and Fe hydroxide precipitates were converted to the oxides by annealing at 700 °C. Boric acid and CaH2 were added in the RE and Fe oxides produced, and this mixture was reduced and diffused to (Nd–Pr)2Fe14B. Magnetic properties of the (Nd–Pr)2Fe14B produced were enhanced by introducing antiferromagnetic coupling, induced by Dy addition and efficient removal of CaO byproduct through ball milling in ethanol which increased the BHmax from 3.9 to 11.45 MGOe. Process reported is energy efficient, environment-friendly, time saving and low-cost.

Geochemical Characteristics of the Soils of the Most Polluted Part of Baley (Zabaykalsky Krai)

The actual material for the present work were the results of elemental analysis of soil samples taken in the Central part of the neighborhood Novotroitsk city Baleya, the section from the former tailings processing plant for the extraction of thorium from monazite concentrate sand through the valley of the river with waste monazite alluvial bulk to the tailings gold processing plants. The interpretation of the obtained data showed high contents of a number of elements, significantly exceeding the MPC. The total indicator of soil pollution (pollution indicator), calculated for five chemical elements (Pb, As, Sb, Ag, Th), indicates a dangerous and extremely dangerous environmental situation for public health and the need for detailed geochemical monitoring of soils. An urgent problem is also the assessment of the contribution of aerosol transport of pollutants during the transportation of sludge from gold recovery factories on the territory of the district Novotroitsk

Optimal Monazite Concentration Processes for the Extraction of Uranium and Thorium Fuel Material

The optimal conditions for the nitric acid dissolution of precipitates of hydroxides and hydrated oxides of rare-earth elements, uranium, and thorium obtained after autoclave alkaline opening of samples of monazite concentrate have been determined. The distribution of radioactive impurities between the solid phase and the solution in the processes of alkaline opening, dephosphorization, and acid dissolution of the pulp was studied. Two options are proposed for the extraction of uranium and thorium in the presence of rare earth elements, followed by separation of the components using tributyl phosphate of various contents in the carbon diluent.