A method for preparing low-magnesium calcium sulfate dihydrate by-product from rare earth sulfate solution

A low-magnesium calcium sulfate dihydrate, rare earth sulfate technology, applied in the direction of calcium/strontium/barium sulfate, process efficiency improvement, etc., can solve the problems of high oxalic acid price, oxalic acid toxicity, high cost, etc., and achieve high rare earth yield, Significant economic benefits and low production costs

Active Publication Date: 2021-10-26
甘肃稀土新材料股份有限公司
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  • Application Information

AI Technical Summary

Problems solved by technology

However, the price of magnesium oxide is more expensive, and the cost is higher compared with calcium hydroxide neutralization
Invention 201310480788.6 discloses a method for separating calcium and magnesium from rare earth industrial wastewater to reduce the calcium content in rare earth industrial wastewater and realize recovery. Sodium oxalate is used as a precipitant to separate calcium and magnesium ions in wastewater, but this method is inevitable Remains of oxalic acid in the decalcified magnesium solution, oxalic acid is toxic, forming another pollution
At the same time, the price of oxalic acid is higher, and the cost of this process is also higher than that of pure magnesium oxide neutralization process

Method used

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  • A method for preparing low-magnesium calcium sulfate dihydrate by-product from rare earth sulfate solution
  • A method for preparing low-magnesium calcium sulfate dihydrate by-product from rare earth sulfate solution
  • A method for preparing low-magnesium calcium sulfate dihydrate by-product from rare earth sulfate solution

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Experimental program
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Effect test

Embodiment 1

[0019] Example 1, take 1 L of a rare earth sulfate solution with a concentration of 30 g / L and an acidity of 0.4 mol / L, and prepare a calcium hydroxide slurry with a mass ratio of calcium hydroxide to aqueous solution of 1:20. The prepared calcium hydroxide slurry was evenly added dropwise to the rare earth sulfate solution at a flow rate of 4.5ml / min with a peristaltic pump under stirring for neutralization reaction. The neutralization reaction temperature was controlled at 40°C, and the reaction time was 60min. : 1.5~2.0, after the reaction, stir and age for 120min, filter the precipitate, the filtrate is clear, and the total rare earth yield of sulfuric acid rare earth solution reaches 99.96%. The prepared CaSO 4 2H 2 O, washed twice with 0.1mol / L dilute sulfuric acid solution, then rinsed once with tap water, the filtrate basically has no rare earth content (trace 0.03g / l), and the rare earth is recovered from the filtrate. Dry the filter cake at 40°C to obtain CaSO 4 2...

Embodiment 2

[0020] Example 2, take 1 L of rare earth sulfate solution with a concentration of 14.5 g / L and an acidity of 0.2 mol / L, and prepare a calcium hydroxide slurry with a mass ratio of calcium hydroxide to aqueous solution of 1:10. The prepared calcium hydroxide slurry was evenly added dropwise into the rare earth sulfate solution at a flow rate of 9ml / min with a peristaltic pump under stirring to carry out neutralization reaction. The neutralization reaction temperature was controlled at 25°C, and the reaction time was 30min. : 1.5~2.0, after the reaction, stir and age for 60min, filter the precipitate, the filtrate is clear, and the total rare earth yield of sulfuric acid rare earth solution reaches 99.95%. The prepared CaSO 4 2H 2 O, wash twice with 0.5mol / L dilute sulfuric acid solution, then rinse once with tap water, the filtrate has almost no rare earth content (trace 0.03g / l), and dry the filter cake at 40°C to obtain CaSO 4 2H 2 O samples. XRD diffraction as image 3 ...

Embodiment 3

[0021] Example 3, take 1 L of a rare earth sulfate solution with a concentration of 24.8 g / L and an acidity of 0.34 mol / L, and prepare a calcium hydroxide slurry with a mass ratio of calcium hydroxide to aqueous solution of 1:10. The prepared calcium hydroxide slurry was uniformly added dropwise into the rare earth sulfate solution at a flow rate of 4.9ml / min with a peristaltic pump under stirring to carry out neutralization reaction. The neutralization reaction temperature was controlled at 30°C, and the neutralization reaction time was 55min. PH: 1.5-2.0, after the reaction, stir and age for 90 minutes, filter the precipitate, the filtrate is clear, and the total rare earth yield of sulfuric acid rare earth solution reaches 99.98%. The prepared CaSO 4 2H 2 O, wash twice with 0.5mol / L dilute sulfuric acid solution, then rinse once with tap water, the filtrate has almost no rare earth content (trace 0.03g / l), and dry the filter cake at 30°C to obtain CaSO 4 2H 2 O sample, X...

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Abstract

The invention relates to a method for preparing low-magnesium calcium sulfate dihydrate by-product from a rare earth sulfate solution. The method uses the rare earth sulfate solution produced in the process of sulfuric acid smelting and separating rare earth concentrate as a raw material, and uses calcium hydroxide as a neutralizing agent. By controlling the concentration of calcium hydroxide slurry, REO concentration in rare earth sulfate solution, reaction time, reaction temperature, neutralization pH value, aging method and other conditions, the yield of rare earth will not be lost, and the supply for downstream rare earth smelting, that is, extraction and separation, will be qualified. Under the condition of rare earth sulfuric acid feed solution, CaSO can be prepared to meet the requirements of cement, building materials, chemical industry and other industries. 4 2H 2 O by-products. And its CaSO 4 2H 2 O quality achieved: m （CaO） ≥30.9%, m （MgO） ≤0.05%. The overall process realizes the lower cost of industrialized production, and lays a solid foundation for green production and circular economic utilization.

Description

technical field [0001] The invention relates to a method for preparing a low-magnesium calcium sulfate dihydrate by-product from a rare earth sulfate solution, and belongs to the technical fields of hydrometallurgy and industrial environmental protection. Background technique [0002] The Baiyan Obo Rare Earth Mine is the largest rare earth mine in the world. Its rare earth minerals are mainly composed of bastnaesite and monazite. At present, more than 90% of the rare earth concentrates are decomposed by concentrated sulfuric acid intensified roasting process. After the concentrate is roasted and decomposed, the rare earths are converted into water-soluble rare earth sulfate forms, which can be leached with water to obtain a rare earth sulfate solution with a certain concentration of rare earths. Because a certain amount of sulfuric acid is entrained in the roasted ore, the acidity of the water leaching solution is relatively high. , the water immersion solution also dissolv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B59/00C22B3/44C01F11/46
CPCC01F11/46C22B3/44C22B59/00Y02P10/20
Inventor 郭小龙白立忠韩满璇李月红李向东马彩红唐东梅范庆忠
Owner 甘肃稀土新材料股份有限公司
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