Method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature

Patent metadata

Field	Value
Publication number	US-2021284531-A1
Application number	US-201616332391-A
Country	US
Kind code	A1
Filing date	Dec 13, 2016
Priority date	Sep 20, 2016
Publication date	Sep 16, 2021
Grant date	—

Abstract

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.

First claim

1 . A method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature, characterized in that: 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; and the solid-state ball milling is carried out in a non-oxidizing atmosphere.

2 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 1 , characterized in that: the molar ratio of the reducing agent to the reduced material is determined as follows:
let the molar amount of magnesium in the reducing agent be n 1 (n 1 ≥0), the molar amount of aluminum element be n 2 (n 2 ≥0), and the molar amount of calcium element be n 3 (n 3 ≥0), and let the number of oxygen in the reduced material be a, then (n 1 +1.5n 2 +n 3 ):a=(3:4) to (4:1).

3 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 1 , characterized in that: the non-oxidizing atmosphere is a mixed atmosphere of argon and hydrogen, or an argon atmosphere, or a hydrogen atmosphere, or vacuum.

4 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 3 , characterized in that: the pressure of the mixed atmosphere of argon and hydrogen is 0-2 MPa, the pressure of the argon atmosphere is 0-2 MPa, and the pressure of the hydrogen atmosphere is 0-2 Mpa.

5 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 1 , characterized in that: the ball mill is a high-energy oscillating ball mill.

6 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 5 , characterized in that: the ball mill has a ratio of grinding media to material of (5-50):1, a ball milling time of 1-20 h, and a rotational speed of 1000-1200 rpm.

7 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 1 , characterized in that: the purification is specifically as follows:
the milled mixture is dissolved in a solvent, and then filtered to obtain a clear filtrate, which is dried to produce purified sodium borohydride powder.

8 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 7 , characterized in that: the solvent is ethylene diamine.

9 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 7 , characterized in that: the drying is vacuum drying.

10 . The method for directly synthesizing sodium borohydride by solid-state ball milling at room temperature according to claim 1 , characterized in that: the sodium metaborate containing crystallization water is sodium metaborate dihydrate or sodium metaborate tetrahydrate.

Assignees

• Univ South China Tech

Inventors

• Ouyang Liuzhang
• Zhong Hao
• Chen Wei
• Wang Hui
• Liu Jiangwen
• Zhu Min

Classifications

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title

• B02C4/00

  Crushing or disintegrating by roller mills (with milling members in the form of rollers or balls co-operating with rings or discs B02C15/00; roller mills or roll refiners exclusively for chocolate A23G1/10, A23G1/12) · CPC title

• C01B3/065 Primary

  by reaction of inorganic compounds with hydrides · CPC title

• C01P2006/82

  water content · CPC title

• C01B6/21 Primary

  Preparation of borohydrides of alkali metals, alkaline earth metals, magnesium or beryllium; Addition complexes thereof, e.g. LiBH4.2N2H4, NaB2H7 · CPC title