Method for extracting and recovering rare earth elements from waste phosphor

Abstract

A method for extracting and recovering rare earth elements from waste phosphor comprises the following steps: (1) concentrated sulfuric acid is added into the waste phosphor, the mixture is uniformly mixed and placed into a high-temperature furnace for roasting, and rare earth is converted into a sulfate form; (2) a solid product after roasting is leached by water, rare earth sulfate enters the water and filtered, a leaching solution after filtering is separated from leaching residues; (3) oxalic acid is added into the leaching solution, pH is adjusted, rare earth is precipitated in a oxalic acid rare earth form, and rare earth oxide is obtained after filtering, drying and roasting. According to the method, the waste phosphor is subjected to processes of sulfatizing roasting, leaching, oxalic acid precipitation, oxalic acid rare earth roasting and the like to recover the rare earth elements in the waste phosphor, the process is simple, the operation is convenient, the cost is lower and the rare earth recovery rate is high.

Description

technical field [0001] The invention relates to the technical field of biological extraction, in particular to a method for extracting and recovering rare earth elements from waste 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 ranks first in the world. According to statistics, the annual output of rare earth fluorescent lamps in my country reaches 3.95 billion, and the consumption of trichromatic rare earth phosphors exceeds 5,700 tons. At the same time, more than 400 million rare-earth fluorescent lamps are discarded in my country every year, and the content of rare-earth fluorescent powder is close to 600 tons. At present, most of these discarded fluorescent lamps enter the landfill with domestic waste and are t...

AI Technical Summary

Problems solved by technology

Supercritical extraction greatly improves the recovery rate and extraction rate of rare earth metals, but the system essentially integrates nitric acid-dissolved phosphor powder with the extraction and separation process, and the uncertainty of the reaction can easily lead to system instability and affect the separation process

Although the above methods have achieved certain research results, there are still problems such as complicated process and low recovery rate of rare earth elements.