The present invention discloses a method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature, which comprises: performing solid-state ball milling on a mixture of a reducing agent and a reduced material by using a ball mill under room temperature, and performing purification to obtain sodium borohydride. The reducing agent comprises one or more of magnesium, magnesium hydride, aluminum, calcium, and magnesium silicide. The reduced material is sodium metaborate containing crystallization water or sodium metaborate, or is a mixture of sodium metaborate containing crystallization water and sodium metaborate. The solid-state milling is performed in a mixed atmosphere of argon and hydrogen, or an argon atmosphere, or a hydrogen atmosphere. The present invention has a simple process, a controllable and adjustable reaction procedure, mild reaction conditions, low energy consumption, low costs, high yield, no pollution, good safety, and easy industrial production.

In a hermetic vessel filled with hydrogen gas, a sodium borate and aluminum powder are reacted at not less than 400° C. and not more than 560° C. while performing stirring to produce sodium borohydride with the molar ratio of sodium contained in the sodium borate being larger than 0.5 relative to boron contained in the sodium borate.

In a hermetic vessel filled with hydrogen gas, a sodium borate and aluminum powder are reacted at not less than 400° C. and not more than 560° C. while performing stirring to produce sodium borohydride with the molar ratio of sodium contained in the sodium borate being larger than 0.5 relative to boron contained in the sodium borate.

A sodium borate, aluminum powder and fluoride powder are mixed together in a hermetic vessel filled with hydrogen gas, and the mixture is reacted at not less than 410° C. and not more than 560° C. to produce sodium borohydride.

A sodium borate, aluminum powder and fluoride powder are mixed together in a hermetic vessel filled with hydrogen gas, and the mixture is reacted at not less than 410° C. and not more than 560° C. to produce sodium borohydride.

A method for obtaining solid-state metal borohydrides without toxic precursors and expensive solvents includes dry mixing of metal hydrides and metal polyhydro-closo-borate starting materials. High pressure and heating is also used in the method. These materials can be used for hydrogen storage, general reducing agents, organic synthesis, wastewater treatment, and paper pulp bleaching.

A method for obtaining solid-state metal borohydrides without toxic precursors and expensive solvents includes dry mixing of metal hydrides and metal polyhydro-closo-borate starting materials. High pressure and heating is also used in the method. These materials can be used for hydrogen storage, general reducing agents, organic synthesis, wastewater treatment, and paper pulp bleaching.

A method for producing a tetrahydroborate includes a hydrogenating step (step S14) of exposing a borate to a hydrogen plasma while grinding the borate.

A method for producing a tetrahydroborate includes a hydrogenating step (step S14) of exposing a borate to a hydrogen plasma while grinding the borate.

The present invention discloses a method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature, which comprises: performing solid-state ball milling on a mixture of a reducing agent and a reduced material by using a ball mill under room temperature, and performing purification to obtain sodium borohydride. The reducing agent comprises one or more of magnesium, magnesium hydride, aluminum, calcium, and magnesium silicide. The reduced material is sodium metaborate containing crystallization water or sodium metaborate, or is a mixture of sodium metaborate containing crystallization water and sodium metaborate. The solid-state milling is performed in a mixed atmosphere of argon and hydrogen, or an argon atmosphere, or a hydrogen atmosphere. The present invention has a simple process, a controllable and adjustable reaction procedure, mild reaction conditions, low energy consumption, low costs, high yield, no pollution, good safety, and easy industrial production.