Method for preparing narrow-distributed ultra-fine yttrium oxide by sodium carbonate precipitation

Abstract

The invention discloses a method for preparing narrow-distributed ultra-fine yttrium oxide by sodium carbonate precipitation. The method utilizes sodium carbonate as a precipitating agent and yttriumchloride as a material liquid and a parallel feeding method, strictly controls the conditions in seed crystal preparation, precipitation aging and staged roasting, especially controls the temperate and pH in the seed crystal preparation and precipitation aging and the temperature in the staged roasting, and prepares the narrow-distributed yttrium oxide powder with the primary particle sizes of less than or equal to 100nm, the secondary particle size D50 of less than or equal to 4 micrometers and (D90-D10) / (2D50) of less than 1.0. The method has the advantages of low cost, easy industrialization and removal of ammonia nitrogen pollution, can transform the advantages of China's plutonium resources into economic advantages and plays an important role in promoting the upgrading of the China'srare earth industry.

Description

technical field [0001] The invention relates to the field of rare earth hydrometallurgy, in particular to a method for preparing narrowly distributed ultrafine yttrium oxide by precipitation of sodium carbonate. Background technique [0002] Yttrium oxide is an important rare earth compound and a key basic raw material for the preparation of rare earth luminescent materials, crystal materials, ceramic materials, catalytic materials and other high-tech materials. With the continuous expansion of its application fields, the relationship between the full manifestation of the intrinsic properties of yttrium element and the material performance indicators has become more and more obvious. In the field of high-tech materials, the quality requirements for rare earth yttrium oxide powder have changed from simple chemical composition and purity requirements to crystal form, A change in the direction of taking into account the control of physical properties such as particle size and d...

AI Technical Summary

Problems solved by technology

However, the ammonium bicarbonate precipitation method commonly used in industry produces a large amount of ammonia nitrogen wastewater, and the concentration is dilute, so it is difficult to treat it up to the standard

Therefore, some enterprises use sodium carbonate, sodium bicarbonate and other precipitants instead. The unit consumption of sodium bicarbonate precipitation is high (6 mol sodium bicarbonate is required to precipitate 2 mol of yttrium), while the consumption of sodium carbonate to precipitate yttrium is low (only 3 mol is required to precipitate 2 mol of yttrium) Sodium carbonate), but the above-mentioned direct precipitation methods such as sodium carbonate and sodium bicarbonate all have the common problem that the direct addition of the precipitant will easily make the concentration of the local precipitant too high, resulting in uneven supersaturation, and it is difficult to achieve fine powder particle size and Organic unity with narrow distribution range, unable to controlly produce ultrafine yttrium oxide powder

In addition, the researchers used the homogeneous precipitation method to solve the problem. This method ensures that the precipitant is uniformly and slowly precipitated in the entire solution through chemical reactions, so that the supersaturation can be controlled within an appropriate range to achieve the goal of controlling the particle growth rate. The purpose is to obtain ultrafine particles with uniform particle size, compactness and high purity, but the disadvantages of this method are that the concentration of reactants is low, the yield is also low, and it is difficult to scale up; and the most commonly used precipitants are urea and hexamethylene tetra Amines, the inevitable introduction of ammonia nitrogen wastewater, limited industrial application