A device and a method for producing high-purity nano molybdenum trioxide are provided. The device comprises a raw material bin (1), a feeding machine (2), a subliming furnace (7), a first vent tube (24), a second vent tube (25), a spraying device (23) and a filtering assembly. The sublimated molybdenum trioxide is cooled with clean and dehumidified air so as to finally obtain the nano molybdenum trioxide, and the recycling mode is reliable, pollution-free and high in efficiency.

A polymerization installation with integrated combined absorption-diffusion and absorption-condensation unit, as well as to its use for the preparation of various polymers and copolymers by addition, emulsion, suspension or radical polymerization, which will find application in chemical industry. There are four structural units in the installation, as follows: supply unit (A), reaction unit (B), combined absorption-diffusion and absorption-condensation unit (C) and finished product discharge unit (D).

A connection pipe for coupling at least one reaction vessel used in producing titanium sponge with at least one recovering vessel for condensing and recovering magnesium and magnesium chloride separated from the titanium sponge in the reaction vessel; wherein the connection pipe is configured as a dual wall structure constituted of an inner pipe and an outer pipe, and comprises at least one heating unit provided between the inner pipe and the outer pipe, two or more sets of lead terminals located through the outer pipe to provide electrical connection to a power terminal in the outside of the connection pipe, insulators for sealing the lead terminals, lead wires for electrically coupling the heating unit with the lead terminals, and a stress absorbed portion provided on the outer pipe; wherein the stress absorbed portion is provided between the lead terminals thereby preventing short circuit and meltdown of the lead wires.

A method and system for formation of a polyarylene sulfide is described. The method includes a first stage in which a complex is formed in a reactor. The complex includes the hydrolysis product of an organic amide solvent and an alkali metal hydrosulfide. The complex formation reaction also forms hydrogen sulfide as a by-product. The method also includes treating a fluid stream that is pulled off of the reactor. The treatment includes scrubbing the fluid stream to recover hydrogen sulfide from the stream and return the hydrogen sulfide to the reactor. The recovery and recycle of the hydrogen sulfide can prevent loss of sulfur from a polyarylene sulfide formation process.

A multi-stage process and system for formation of a polyarylene sulfide is described. The multi-stage process can include at least three separate formation stages that can take place in three different reactors. The first stage of the formation process can include reaction of an alkali metal sulfide with an organic amide solvent to form a complex including a hydrolysis product of the solvent and an alkali metal hydrogen sulfide. The second stage of the formation process can include reaction of the complex formed in the first stage with a dihaloaromatic monomer to form a prepolymer, and the third stage can include further polymerization of the prepolymer with additional monomers to form the final product.