Respective recovery method for rare earth concentrate multi-stage baking tail gases, and device thereof

Abstract

The present invention provides a respective recovery method for rare earth concentrate multi-stage baking tail gases, and a device thereof. The method comprises the following steps: 1, collecting the tail gases: the tail gas generated from first stage baking is introduced into a first tubular heat exchanger (1), and the tail gas generated from second stage baking and the tail gas generated from later stage baking are mixed and introduced into a second tubular heat exchanger (2); 2, condensing and absorbing: the tail gas generated from the first stage baking is subjected to self-condensation in the first tubular heat exchanger (1) to generate a hydrofluoric acid-rich cooling liquid, and the mixture comprising the tail gases generated from the second stage baking and the later stage baking is subjected to self-condensation in the second tube alignment heat exchanger (2) to generate a sulfuric acid-rich cooling liquid. According to the present invention, the tail gases generated from the first stage baking, the second stage baking and the later stage baking are respectively treated, and the recovery treatments are concurrently performed to obtain the hydrofluoric acid-rich cooling liquid or the sulfuric acid-rich cooling liquid, and the high concentration sulfuric acid can be obtained without the sulfuric acid concentration process.

Description

technical field [0001] The invention relates to the technical field of rare earth wet production technology, in particular to a method for separately recovering the roasting tail gas produced by the multi-stage roasting method of rare earth concentrate, especially a rare earth fluorocarbonate (REFCO 3 ), rare earth phosphate (REPO 4 ), Fluorite (CaF 2 )-based method of recovering the roasting tail gas produced by the multi-stage roasting method of concentrated sulfuric acid of mixed rare earth concentrate. The invention also relates to a device for separately recovering tail gas from multi-stage roasting of rare earth concentrate. Background technique [0002] Rare earth concentrate is a mixed rare earth concentrate mainly composed of rare earth fluorocarbonate, rare earth phosphate and fluorspar. my country is rich in rare earth concentrate resources, accounting for nearly 50% of the world's reserves. [0003] The mineral decomposition method of this kind of mixed rare ...

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Problems solved by technology

[0014] The technical problem to be solved by the present invention is to overcome the defects of difficulty in recovery of hydrofluoric acid and complicated rare earth roasting tail gas treatment process in the rare earth concentrate roasting tail gas treatment method, and to provide a separate recovery method for rare earth concentrate multi-stage roasting tail gas. Hydrofluoric acid (HF)-based roasting tail gas produced by first-stage roasting, roasting tail gas mainly sulfuric acid and only trace hydrofluoric acid produced by second- and subsequent-stage roasting, hydrofluoric acid and sulfuric acid are recovered at the same time, and no need Sulfuric acid concentration process can get high concentration of sulfuric acid

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