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A method for preparing high-purity porous silicon dioxide from waste circuit boards

A technology of porous silica and waste circuit boards, applied in the field of environmental engineering, can solve the problems of low utilization value, waste of resources, and few utilization methods, etc.

Inactive Publication Date: 2018-08-21
FUJIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are not many ways to utilize non-metallic powders that account for about 70% of the weight of circuit boards. The main components of non-metallic powders are thermosetting resins, glass fibers, ceramic materials, brominated flame retardants, residual metals and other additives. It is directly landfilled or simply used as a filler for other materials, which has low utilization value and causes a great waste of resources.

Method used

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  • A method for preparing high-purity porous silicon dioxide from waste circuit boards

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Experimental program
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Effect test

Embodiment 1

[0015] Such as figure 1 As shown, firstly, the waste circuit board non-metallic powder is mixed with 2mol / L dilute hydrochloric acid at a solid-to-liquid ratio of 1:25g / mL, and heat pretreatment is performed at 90°C. The purpose of pretreatment is to remove waste circuit board non-metallic powder. Residual metal elements in the metal powder, pretreatment for 5 hours; filter, wash and dry the precipitate. The non-metallic powder of waste circuit board after hydrochloric acid pretreatment was subjected to subcritical water oxidation activation. The subcritical water oxidation activation process can achieve two goals: one is to decompose and remove the organic materials containing brominated flame retardants, and the other is to activate and prepare porous silica. The specific process of subcritical water oxidation activation is as follows: control the temperature of the subcritical water oxidation reactor to 250°C, the pressure to 5 MPa, and the reaction time to 30 minutes. Aft...

Embodiment 2

[0017] Such as figure 1 As shown, firstly, the waste circuit board non-metallic powder is mixed with 2mol / L dilute hydrochloric acid at a solid-to-liquid ratio of 1:25g / mL, and heat pretreatment is performed at 90°C. The purpose of pretreatment is to remove the waste circuit board non-metallic powder The residual metal elements in the solution were pretreated for 5 hours, filtered, and the precipitate was washed and dried. The non-metallic powder of waste circuit board after hydrochloric acid pretreatment was subjected to subcritical water oxidation activation. The subcritical water oxidation activation process can achieve two goals: one is to decompose and remove the organic materials containing brominated flame retardants, and the other is to activate and prepare porous silica. The specific process of subcritical water oxidation activation is as follows: control the temperature of the subcritical water oxidation reactor to 300°C, the pressure to 7MPa, and the reaction time ...

Embodiment 3

[0019] Such as figure 1 As shown, first mix the non-metallic powder of the waste circuit board with 2mol / L dilute hydrochloric acid at a solid-to-liquid ratio of 1:25g / mL, and perform heating pretreatment at 90°C. The purpose of the pretreatment is to remove the non-metallic powder of the waste circuit board Residual metal elements in the solution were pretreated for a certain period of time for 5 hours, filtered, and the precipitate was washed and dried. The non-metallic powder of waste circuit board after hydrochloric acid pretreatment was subjected to subcritical water oxidation activation. The subcritical water oxidation activation process can achieve two goals: one is to decompose and remove the organic materials containing brominated flame retardants, and the other is to activate and prepare porous silica. The specific process of subcritical water oxidation activation is as follows: control the temperature of the subcritical water oxidation reactor to 350°C, the pressur...

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Abstract

A disclosed method for preparing high-purity porous silicon dioxide by using waste circuit boards comprises the following steps: mixing a non-metal powder of waste circuits and diluted hydrochloric acid with the concentration of 2 mol / L according to the solid-liquid ratio of 1:25 g / mL, and heating at 90 DEG C for 5 h; after heating is finished, filtering, washing and drying the precipitate obtained through filtering, so as to obtain a pre-product; and adding the pre-product into a subcritical water oxidation reaction kettle; performing subcritical water oxidation reaction at a temperature of 250-350 DEG C under a pressure of 5-10 MPa, and reacting for 30-60 min; and after the reaction is finished, cooling the reaction kettle to room temperature, filtering the cooled product, and washing and drying the precipitate obtained through filtering, so as to obtain the high-purity porous silicon dioxide material. According to the method, the high-purity porous silicon dioxide material with high added value is prepared by employing a hydrochloric acid pretreatment and subcritical water oxidation activation technology and activating the non-metal powder of waste circuit boards.

Description

technical field [0001] The invention belongs to the field of environmental engineering, and in particular relates to a method for preparing high-purity porous silicon dioxide from waste circuit boards. Background technique [0002] In recent years, with the acceleration of the replacement of electronic products and the shortening of the life cycle of electronic products, a large number of discarded electronic products pose a huge threat to environmental safety. As the most basic component of electronic products, the safe and efficient disposal or resource utilization of waste circuit boards has become the focus of attention from all walks of life. At present, the recycling of waste circuit boards mainly adopts mechanical crushing to dissociate the metal in the circuit boards, and then separates metal materials and non-metal materials through electrostatic, magnetic, gravity and other sorting methods. Metal powders are of high value and can be sold directly on the market. H...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/18
CPCC01B33/18C01P2006/12C01P2006/80
Inventor 修福荣齐莹莹翁慧玮
Owner FUJIAN UNIV OF TECH