Efficient leaching technology of metal ions in chrysotile nanofiber

A nanofiber and chiropterite technology, which is applied in the field of efficient leaching of metal ions in silica nanofibers, can solve the problems of low pH value of tail acid, environmental hazards, high acid concentration, etc., achieve efficient leaching and reduce environmental costs Effect

Inactive Publication Date: 2012-02-15
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of technological process is simple and can effectively utilize resources such as magnesium and silicon in serpentine, but the disadvantage is that the concentration of the acid used is too high, such as 31% concentrated hydrochloric acid (patent 200610030750.9, etc.), 40-60% hydrochloric acid Concentrated sulfuric acid (patent 200810058252.4, 01131802.3, etc.), etc., which not only increases the burden on equipment and personnel in the leaching process, but also has a too low pH value of the tail acid formed, which is not conducive to neutralization treatment, or causes potential harm to the environment
Although high-concentration acid can effectively leach the metals in the chrysotile nanofibers to form high-purity silica, it is easy to cause fiber breakage during the leaching process and reduce the aspect ratio of the product silica nanofibers.
At the same time, due to the strong thickening property of the chrysotile nanofibers, the low liquid-solid ratio makes stirring and leaching impossible.
Due to the characteristics of this kind of chrysotile nanofibers that are not resistant to strong acid and thickening, the previously developed serpentine acid leaching process characterized by high concentration of acid and low liquid-solid ratio cannot be applied to it.

Method used

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  • Efficient leaching technology of metal ions in chrysotile nanofiber
  • Efficient leaching technology of metal ions in chrysotile nanofiber

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Two-stage hydrochloric acid countercurrent leaching, see the flow chart figure 1 . Hydrochloric acid solution with a hydrogen ion concentration of 0.8 mol / L was used as the leaching agent, and hydrochloric acid was added at a solid-to-liquid ratio of 1:50 g / ml. The leaching time of each section was 2 h, the temperature was 80 ° C, and the stirring speed was 500 rpm. Fresh chrysotile nanofiber solids were added in the first stage, and fresh acid was added in the second stage. The direction of the solid is one stage → two stages, and the direction of the liquid is two stages → one stage. At the same time, add 2% leaching aid oxalic acid in the second stage. The pH of the tail acid discharged after the first stage of leaching is measured each time. After 8 to 10 batches of leaching, the pH value of the tail acid is stable at about 0.8, and the countercurrent leaching system reaches equilibrium. After the solid discharged from the second stage is washed with hydrochloric...

Embodiment 2

[0036] The operation process is the same as in Example 1, except that the hydrochloric acid solution with a hydrogen ion concentration of 0.5 mol / L is used as the leaching agent, and hydrochloric acid is added at a solid-to-liquid ratio of 1:80 g / ml. The leaching time of each section is 4 hours, and the temperature is 95 ° C. The stirring speed is 700 rpm. Add 8% leaching aid sodium citrate in the second stage. The pH of the tail acid discharged after the first stage of leaching is measured each time. After 8 to 10 batches of leaching, the pH value of the tail acid is stable at about 0.8, and the countercurrent leaching system reaches equilibrium. After the solid discharged from the second stage is washed with hydrochloric acid of pH=2 and deionized water several times, silicon oxide nanofibers with a purity greater than 92% are obtained.

Embodiment 3

[0038] The operation process is the same as in Example 1, except that the hydrochloric acid solution with a hydrogen ion concentration of 1.0 mol / L is used as the leaching agent, and hydrochloric acid is added at a solid-to-liquid ratio of 1:40 g / ml. The leaching time of each section is 1 h, and the temperature is 60 ° C. The stirring speed is 400 rpm. Add 5% leaching aid sodium oxalate in the second stage. The pH of the tail acid discharged after the first stage of leaching is measured each time. After 8 to 10 batches of leaching, the pH value of the tail acid is stable at about 0.8, and the countercurrent leaching system reaches equilibrium. After the solid discharged from the second stage is washed with hydrochloric acid of pH=2 and deionized water several times, silicon oxide nanofibers with a purity greater than 92% are obtained.

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Abstract

The invention provides an efficient leaching technology of metal ions in chrysotile nanofiber and particularly relates to an efficient leaching technology of metal ions in silicon oxide nanofiber prepared from chrysotile, belonging to the fields of mineral materials and mineral processing. The efficient leaching technology uses chrysotile nanofiber as a raw material and one or more of low concentration sulphuric acid, hydrochloric acid and nitric acid as a leaching agent; and the countercurrent leaching technology with 2-4 sections is adopted, the efficient leaching of chrysotile nanofiber is performed for a proper time at the atmospheric pressure and at a proper temperature, the acid-leaching product is washed with dilute acid and water in sequence, and finally the silicon oxide nanofiber with higher purity can be obtained. By adopting the technology, the efficient leaching of metal ions can be effectively realized while the large length-diameter ratio of the product silicon oxide nanofiber can be maintained; and the equipment is simple, the operations are convenient, the acid consumption is extremely low, the pH value of the discharged tail acid is about 1 after the balance of the system, the subsequent magnesium extraction and neutralization treatment are performed easily and the environmental cost is reduced extremely.

Description

technical field [0001] The invention relates to a high-efficiency leaching process of metal ions in chrysotile nanofibers, in particular to a high-efficiency leaching method of metal ions in silicon oxide nanofibers prepared from chrysotile, and belongs to the field of mineral materials and mineral processing. Background technique [0002] Serpentine is a natural magnesium-containing silicate mineral. It is a 1:1 type layered silicate mineral composed of silicon-oxygen tetrahedral sheets and magnesia octahedral sheets. According to the different crystal internal structures It is mainly divided into three mineral species: lizardite, antigorite and chrysotile. The ideal chemical formula for serpentine is Mg 3 [Si 2 o 5 ](OH) 4 , where MgO content is 43.0%, SiO 2 The content is 44.1%. In addition, many metals exist in the serpentine lattice in the form of isomorphic substitution, including rare metals such as nickel, titanium, chromium, and palladium. As early as the 194...

Claims

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Application Information

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IPC IPC(8): C22B3/06C01B33/12
CPCY02P10/20
Inventor 刘琨冯其明张国范欧乐明卢毅屏
Owner CENT SOUTH UNIV
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