Extracting fibres from fibre feedstock

Abstract

A method of extracting natural fibres from a fibre feedstock, the fibre feedstock comprising gum between the natural fibres. Fibre feedstock is introduced into water with a first oxidizing agent. The first oxidizing agent partially reacts with the gum. The oxidizing agent is modified, such as by introducing a second oxidizing agent or reducing the concentration of the first oxidizing agent, and reacts with the partially reacted gum. The released fibres are then removed from the water.

What is claimed is: 
     
         1 . A method of extracting natural fibres from a fibre feedstock, the fibre feedstock comprising gum between the natural fibres, the method comprising:
 introducing fibre feedstock into water;   introducing a first oxidizing agent into the water and causing the first oxidizing agent to partially react with the gum;   selectively introducing a second oxidizing agent into the water to react with the partially reacted gum, the second oxidizing agent being more reactive than the first oxidizing agent; and   removing released fibres from the water.   
     
     
         2 . The method of  claim 1 , wherein the fibre feedstock is contained within a water-permeable container placed in a tank filled with water, and further comprising the step of agitating the fibre feedstock in the water by rotating the water-permeable container. 
     
     
         3 . The method of  claim 1 , further comprising the step of agitating the fibre feedstock by generating turbulence in the water. 
     
     
         4 . The method of  claim 1 , wherein the first oxidizing agent comprising oxygen, ozone, or a mixture of oxygen and ozone. 
     
     
         5 . The method of  claim 1 , wherein the first oxidizing agent is introduced using a manifold, a diffusion apparatus, or combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein the second oxidizing agent comprises hydroxyl radicals. 
     
     
         7 . The method of  claim 6 , wherein introducing hydroxyl radicals comprises generating the hydroxyl radicals in the water. 
     
     
         8 . The method of  claim 6 , wherein introducing the second oxidizing agent comprises concentrating the hydroxyl radicals in a limited volume of the water. 
     
     
         9 . The method of  claim 1 , wherein the second oxidizing agent is introduced into the water after the first oxidizing agent generates reaction products. 
     
     
         10 . The method of  claim 1 , further comprising the step of exposing the fibre feedstock to UV light, to ultrasonic energy, or combinations thereof. 
     
     
         11 . The method of  claim 1 , further comprises the step of removing the gases and dissolved gases from the water by selectively injecting compressed air into the water. 
     
     
         12 . An apparatus for extracting natural fibres from fibre feedstock that comprises gum between the natural fibres, comprising:
 a tank that contains water, the tank being capable of receiving the fibre feedstock;   a source of a first oxidizing agent;   a source of a second oxidizing agent, wherein the second oxidizing agent is more reactive than the first oxidizing agent;   a controller that:
 controls the source of the first oxidizing agent to introduce the first oxidizing agent into the water, the first oxidizing agent being capable of partially reacting with the gum of the fibre feedstock; and 
 selectively controls the source of the second oxidizing agent to introduce the second oxidizing agent into the tank to react with the partially reacted gum. 
   
     
     
         13 . The apparatus of  claim 12 , wherein the fibre feedstock is contained within a water permeable container within the tank, and the apparatus further comprises an actuator that rotates the container. 
     
     
         14 . The apparatus of  claim 12 , further comprising an agitator that generates turbulence in the water. 
     
     
         15 . The apparatus of  claim 12 , wherein the first oxidizing agent comprises oxygen, ozone, or a mixture thereof. 
     
     
         16 . The apparatus of  claim 12 , wherein the source of the first oxidizing agent comprises a diffuser and/or manifold in the tank. 
     
     
         17 . The apparatus of  claim 12 , wherein the source of the second oxidizing agent comprises a generator that generates hydroxyl radicals. 
     
     
         18 . The apparatus of  claim 12 , further comprising an ultrasonic transducer, a UV light source, or both an ultrasonic transducer and a UV light source in the tank. 
     
     
         19 . The apparatus of  claim 12 , further comprising an air injector adapted to inject air into the water of the tank and controlled by the controller. 
     
     
         20 . A method of extracting natural fibres from fibre feedstock that comprises gum adhered to the natural fibres, the method comprising:
 introducing the fibre feedstock into water;   in a first stage, injecting an oxidizing agent into the water and permitting the oxidizing agent to react with the gum, the oxidizing agent inducing an oxidation reduction potential (ORP) in the water, and wherein a sufficient amount of oxidizing agent is introduced to achieve a first ORP level; and   in a second stage, controlling an amount of oxidizing agent introduced into the water to reduce the ORP and permitting the oxidizing agent to continue reacting with the gum until the ORP is at or below a second ORP level; and   removing released fibres from the water.   
     
     
         21 . The method of  claim 20 , wherein the first ORP level is at least 500 mv. 
     
     
         22 . The method of  claim 20 , further comprising the step of filtering the water to remove released gum after the first ORP level has been achieved. 
     
     
         23 . The method of  claim 20 , wherein the second ORP level is 300 mv. 
     
     
         24 . The method of  claim 20 , wherein the gum comprises proteins, and in the first stage, the oxidizing agent denatures at least a portion of the proteins on exterior surfaces of the fibre feedstock. 
     
     
         25 . The method of  claim 20 , wherein a second oxidizing agent is injected into the water during or after the second stage. 
     
     
         26 . The method of  claim 20 , wherein the water is agitated during the first stage and the second stage.