Method for cleanly and efficiently extracting rare earth elements from waste fluorescent powder

Abstract

The invention relates to a method for cleanly and efficiently extracting rare earth elements from waste fluorescent powder, and belongs to the technical field of recycling the waste rare earth fluorescent powder. The waste fluorescent powder and alkali are mixed evenly at the mass ratio of 1:(0.1-10), and a mixture is obtained; the obtained mixture is heated to the temperature of 300-800 DEG C atthe microwave power of 1-5 kW to be subjected to low-temperature calcination for 0.5-1 h, and a calcined material is obtained; the calcined material is ground into powder, then a water solution is added according to the liquid-solid ratio of (1-6):1 ml / g, water leaching is carried out at the temperature of 25-80 DEG C for 5-30 min, after solid-liquid separation, water leaching residues and aluminum-containing aqueous leachate are obtained, and the water leaching residues are repeatedly water-leached 1-5 times; and a hydrochloric acid solution is added into the water leaching residues accordingto the liquid-solid ratio of (5-10):1 ml / g, acid leaching is carried out at the temperature of 25-80 DEG C for 0.5-2 h, and after solid-liquid separation, leaching residues and rare-earth-containingleachate are obtained. The method has the beneficial effects of being low in cost and high in rare earth recovery rate, achieving energy saving and environmental friendliness and the like.

Description

technical field [0001] The invention relates to a method for cleanly and efficiently extracting rare earth elements from waste fluorescent powder, and belongs to the technical field of recycling and utilization of waste rare earth fluorescent powder. Background technique [0002] Rare earth fluorescent lamps have been widely used in lighting systems in most countries at home and abroad due to their advantages of energy saving and environmental protection. At present, the production and usage of rare earth fluorescent lamps in my country rank first in the world. At the same time, a large number of rare earth fluorescent lamps are discarded in my country every year. Most of these discarded fluorescent lamps enter the landfill with domestic waste and are treated as solid waste. This not only causes the release of mercury in fluorescent lamps to pollute the environment, but also causes a great waste of rare earth resources. . As an important raw material of new materials of the...

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Problems solved by technology

Selective redox method can obtain high-quality yttrium oxide and europium oxide products, but its production process is complicated and the recovery cost is high

[0004] There have been many studies on the recovery of rare earths from waste phosphor powder at home and abroad, but because the blue powder and green powder in the phosphor powder belong to the magnesium aluminum spinel structure, it is difficult to destroy its structure by conventional acid leaching, and it is difficult to destroy the structure by alkaline roasting. It can decompose blue powder and green powder, but it usually needs to be roasted at a high temperature above 800°C for several hours, and the decomposition of phosphor powder is still not complete, and the leaching rate of rare earth Tb and Ce is still low, so the conventional alkaline roasting process has energy consumption Large size, high cost, large amount of alkali consumption, and low comprehensive recovery rate of rare earth

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