Method for preparing thorium oxide by utilizing monazite excellent molten slag

Abstract

The invention discloses a method for preparing thorium oxide by using monazite excellent molten slag. The method comprises the following steps: carrying out reselection or magnetic separation treatment on the monazite excellent molten slag, and carrying out filter pressing treatment to obtain corresponding filter residues A; sequentially performing hydrochloric acid dissolution, ammonium bicarbonate precipitation treatment and filter pressing treatment on the filter residues A to obtain corresponding filter residues B, and repeatedly performing hydrochloric acid dissolution, sodium carbonate precipitation and filter pressing treatment on the filter residues B to obtain neutral filtrate C; carrying out suction filtration treatment on the filtrate C to obtain filtrate D, slowly adding hydrochloric acid into the filtrate D, and filtering to obtain thorium-uranium carbonate precipitate; slowly adding hydrochloric acid into the thorium carbonate uranium precipitate until the pH value of the solution is 1, and carrying out counter-current extraction and back extraction to obtain raffinate E; and adding an oxalic acid solution into the raffinate D for treatment to obtain thorium oxalate precipitate, and continuing drying and roasting treatment to obtain thorium oxide powder. According to the method, the aim of avoiding multiple times of extraction for extracting thorium from the monazite excellent molten slag is achieved.

Description

technical field

[0001] The invention relates to the technical field of chemical smelting, in particular to a method for preparing thorium oxide by using monazite slag. Background technique

[0002] Monazite is an important phosphate rare earth mineral, often accompanied by more radioactive elements such as thorium and uranium, and a small amount of rutile, ilmenite, zircon and quartz and other minerals. The decomposition methods commonly used in industry mainly include sulfuric acid, soda ash roasting method, and sodium hydroxide alkali boiling decomposition method. At present, the most widely used method is sodium hydroxide alkali boiling decomposition method. Monazite concentrate is heated to 130-160°C in a sodium hydroxide solution to undergo a solid-liquid multiphase reaction, and the decomposition degree of rare earth, thorium, and uranium is affected by various factors. After decomposing and washing the alkali-soluble substances, an alkali cake composed of hydroxide p...

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