A mixing apparatus includes a phosphoric acid aqueous solution supply, an additive supply, a tank, a phosphoric acid aqueous solution supply path and an additive supply path. The phosphoric acid aqueous solution supply is configured to supply a phosphoric acid aqueous solution. The additive supply is configured to supply an additive configured to suppress precipitation of a silicon oxide. The phosphoric acid aqueous solution supply path is configured to connect the phosphoric acid aqueous solution supply with the tank. The additive supply path is configured to connect the additive supply with the tank. The additive is supplied while fluidity is imparted to the phosphoric acid aqueous solution supplied from the phosphoric acid aqueous solution supply into the tank.

There is provided methods and systems for disaggregation and deagglomeration of small scale materials such as carbon nanotubes by cavitation of a treatment substance. The treatment substance may be a substance such as CO.sub.2 which is capable of undergoing phase changes. Systems must be capable of withstanding high pressures, and cavitation may be done by ultrasound, mechanical agitation, injection of a jet stream, or other methods. Materials treated via the methods of the invention may be removed without the use of chemical surfactants or other chemical modification means, and may be further used in a battery.

A mixing apparatus includes a phosphoric acid aqueous solution supply, an additive supply, a tank, a phosphoric acid aqueous solution supply path and an additive supply path. The phosphoric acid aqueous solution supply is configured to supply a phosphoric acid aqueous solution. The additive supply is configured to supply an additive configured to suppress precipitation of a silicon oxide. The phosphoric acid aqueous solution supply path is configured to connect the phosphoric acid aqueous solution supply with the tank. The additive supply path is configured to connect the additive supply with the tank. The additive is supplied while fluidity is imparted to the phosphoric acid aqueous solution supplied from the phosphoric acid aqueous solution supply into the tank.