A method of recycling indium in waste liquid crystal display

A liquid crystal display and solution technology, applied in the direction of improving process efficiency, can solve the problems of secondary pollution, consumption of large chemical reagents, and lengthy processes, and achieve the effect of high recovery rate, promotion of development, and promotion of circular economy.

Active Publication Date: 2021-03-30
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of method has lengthy procedures and consumes a large amount of chemical reagents, which is prone to secondary pollution

Method used

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  • A method of recycling indium in waste liquid crystal display
  • A method of recycling indium in waste liquid crystal display
  • A method of recycling indium in waste liquid crystal display

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1: [Hbet][Tf 2 N]-H 2 O system extraction

[0031] Using the single factor control variable method, the study of 10-60 (v / v)% different proportions of [Hbet][Tf 2 N]-H 2 O mixed solution in a 10mL serum bottle, add 0.2g glass powder, set the heating temperature of 70, 80, 90°C in the oil bath, and the leaching effect of indium under different time series conditions such as 16, 20, 24, 28h, etc., to determine Optimal leaching experimental conditions. After the reaction is over, use a 0.22um nylon 66 membrane to quickly filter in the temperature range of 70-90°C to achieve solid-liquid separation. The obtained leaching solution was diluted with 5 (v / v)% nitric acid and analyzed for metal content with an inductively coupled plasma emission spectrometer. The effect of different leaching conditions on the leaching efficiency is as follows: figure 1 shown. figure 1 (a) shows that [Hbet][Tf 2 The increase of N] concentration is beneficial to improve the leachin...

Embodiment 2

[0033] Example 2: [Hbet][Tf 2 N]-ascorbic acid system extraction

[0034] At [Hbet][Tf 2 N]-H 2 In the O system, all the leaching of indium was realized and metal ions such as aluminum and calcium were effectively separated, but [Hbet][Tf 2 The separation effect of N] on Fe(Ⅲ) needs to be improved, which will cause the separation effect of indium and iron to be insignificant. Ascorbic acid can reduce Fe(III) to Fe(II), increasing the separation effect of indium and iron. Therefore, on the basis of the optimal leaching conditions, replace the same amount of water with 0.01M ascorbic acid solution, that is, form [Hbet][Tf 2 N]-ascorbic acid system, its effect is as image 3 shown. It can be seen from the figure that the leaching rate of indium is 99.75%, and the extraction rate is 98.63%. 2 N]-H 2 Compared with the O system, there is no obvious difference, but the difference is that the extraction rate of iron is reduced from 59.87% to 8.84%, which effectively promotes t...

Embodiment 3

[0036] Embodiment 3: washing and recovery of ionic liquid

[0037] Fully mix the indium-containing ionic liquid in the lower layer with 0.5M oxalic acid solution at a ratio of 1:1 (v / v), centrifuge at 10,000 rpm for 10 minutes to promote the separation of the two-phase solution, and measure the oxalic acid solution with an inductively coupled plasma emission spectrometer and the type and content of metals in the organic phase. Oxalic acid is used as a cleaning agent for ionic liquids, and metal ions are transferred to the oxalic acid solution, and its effect is as follows: Figure 5 shown. It can be seen from the figure that 95.71% of indium and other metal ions are transferred to the oxalic acid solution. After washing with oxalic acid, the ionic liquid was washed 4 times with ice water, and the obtained clean ionic liquid could be reused, and the reuse effect was as follows: Figure 6 shown. It can be seen from the figure that during secondary utilization, the leaching r...

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Abstract

The invention belongs to the field of national scarce resource recycling, and discloses a method for recycling indium in a waste liquid crystal display. The method for recycling the indium in the waste liquid crystal display comprises the following steps of (1) crushing the waste liquid crystal display into glass powder, and carrying out high-temperature leaching reaction in an acidic ionic liquidsystem; (2) carrying out solid-liquid separation on the reaction product obtained in the step (1), cooling and layering a leaching agent, and extracting to obtain an ion liquid organic phase containing the indium; and (3) reacting the ion liquid organic phase containing the indium obtained in the step (2) and an oxalic acid solution, fully vibrating, centrifugally layering to obtain an indium-containing oxalic acid solution on the upper layer and ionic liquid on the lower layer, and separating to obtain an oxalic acid-containing solution. According to the method for recycling the indium in the waste liquid crystal display provided by the invention, an acid leaching and extracting integration process is effectively realized, a process flow is simplified, the indium leaching separation efficiency is high, and the environment pollution is reduced; and meanwhile, the ionic liquid can be recycled, so that the usage amount of a chemical agent is reduced, and a new method is provided for waste treatment and recycle.

Description

technical field [0001] The invention belongs to the field of recycling and utilization of national scarce resources, and in particular relates to a method for synchronously leaching and extracting indium in waste liquid crystal display screens with an acidic ionic liquid. Background technique [0002] Indium is an important strategic resource with limited global reserves. Nearly 70% of indium resources are used to manufacture indium tin oxide, an important component of liquid crystal displays in electronic products. Technological innovation has rapidly increased the amount of scrapped electronic products. Recycling waste LCD screens can not only solve the environmental pollution caused by it, but more importantly, it can realize the recycling and reuse of metal resources. At present, the recovery technologies for indium resources in waste liquid crystal displays mainly adopt vacuum carbonization / chlorination, bioleaching and hydrometallurgical processes dominated by chemical...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B58/00
CPCC22B7/007C22B58/00Y02P10/20
Inventor 朱能武罗德亮李遥吴平霄
Owner SOUTH CHINA UNIV OF TECH
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