Method for recovery of carbon fiber by use of low temperature molten salt

Abstract

The invention discloses a method for recovery of carbon fiber from a thermosetting polymer based carbon fiber reinforced polymer material by use of a unitary, binary composite or ternary composite low temperature molten salt system (melting range: 100-400 DEG C). A composite molten salt is prepared in a certain proportion, and then is heated to melt, a carbon fiber reinforced polymer material is added into the composite molten salt for heating until the carbon fiber is separated, the carbon fiber is dragged out and put into water for cleaning, the carbon fiber suspends in the upper layer of the solution, and polymer degradation matters sink to the bottom. The method is simple in process and easy to control, and has no need of large and special instrument equipment, no toxic and harmful gas emissions in a treatment process, and no waste liquids and other secondary pollution after treatment, the carbon fiber is easy to separate, and at the same time inorganic salts dissolved in the water can be recovered and recycled, so that the method has economic, efficient, green and other advantages.

Description

technical field [0001] The invention relates to a technology for treating carbon fiber reinforced polymer recycled carbon fiber with a single, binary composite or ternary composite molten salt system with a melting point in the range of 100°C-400°C. Background technique [0002] Based on environmental protection and its own economic value, it is of great significance to recover carbon fiber materials from carbon fiber reinforced polymer materials. However, there is no particularly effective recycling method for thermosetting polymer-based CFRP, and various methods still have different shortcomings. [0003] According to whether the recovery process uses media, the current treatment methods can be divided into two categories: one is the use of chemical media (organic solvents or concentrated nitric acid), including supercritical methods, solvothermal methods, microwave methods, etc.; the other is no media, For example pyrolysis. [0004] Pyrolysis is currently the only comm...

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Problems solved by technology

[0004] Pyrolysis is currently the only commercial technology that can be mass-produced. However, this method consumes a lot of energy because the processing temperature is generally not lower than 300°C (440-550°C is a commonly used temperature range). On the other hand, high temperature is also easy to cause damage and damage to the performance of carbon fiber, reducing its mechanical properties

Media methods (supercritical, solvothermal, microwave, common heating) have lower temperatures (generally less than 240°C) compared to pyrolysis, however in such methods, for sealed sys

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