Method for preparing lithium borohydride by means of solid-phase ball milling at room temperature

Patent metadata

Field	Value
Publication number	US-11807540-B2
Application number	US-201816977705-A
Country	US
Kind code	B2
Filing date	Oct 30, 2018
Priority date	Mar 14, 2018
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

A method for preparing lithium borohydride by means of room temperature solid phase ball milling, comprising the following steps: uniformly mixing a magnesium-containing reducing agent and a lithium metaborate-containing reducing material under a non-oxidizing atmosphere at room temperature, performing solid phase ball milling, isolating and purifying to obtain lithium borohydride. The method has the advantages of having a simple process, having a controllable and adjustable reaction procedure, having mild reaction conditions, energy consumption being low, costs being low, and output being high, while creating no pollution, being safe and cyclically using boron resources, having important practical significance.

First claim

What is claimed is:

1. A method for preparing lithium borohydride by means of solid-phase ball milling at room temperature, comprising the following steps:
under room temperature and non-oxidizing atmosphere, solid-phase ball milling, separating, and purifying uniformly mixed magnesium-containing reducing agent and a lithium metaborate-based material to obtain the lithium borohydride (LiBH 4 );
wherein the magnesium-containing reducing agent is one or more selected from the group consisting of magnesium, aluminum magnesium and calcium magnesium alloys;
the lithium metaborate-based material is composed of both hydrous lithium metaborate and anhydrous lithium metaborate, or the lithium metaborate-based material is hydrous lithium metaborate; and
the non-oxidizing atmosphere is an argon atmosphere or a mixed atmosphere of argon and hydrogen; the non-oxidizing atmosphere holds a pressure of 0-3 MPa.

2. The method of claim 1 , wherein the lithium metaborate-based material is hydrous lithium metaborate; wherein the hydrous lithium metaborate comprises LiBO 2 ·2H 2 O, LiBO 2 ·8H 2 O or LiBO 2 ·1/2H 2 O.

3. The method of claim 1 , wherein a mixing ratio of the magnesium-containing reducing agent to the lithium metaborate-based material is determined by:
( n 1 +1.5 n 2 +n 3 ): x =(1:1)˜(2.5:1)

wherein n 1 ≥0, n 2 ≥0, n 3 ≥0,
wherein a mole number of magnesium is n 1 , a mole number of aluminum is n 2 , a mole number of calcium is n 3 in the magnesium-containing reducing agent; wherein n 1 ≥0, n 2 ≥0, n 3 ≥0;
wherein x=2 or 4,
wherein a mole number of oxygen is x in the lithium metaborate-based material.

4. The method of claim 1 , wherein the ratio of ball-to-powder for the solid-phase ball milling is 10:1 to 70:1.

5. The method of claim 1 , wherein the rotating speed for the solid-phase ball milling is 1000 to 1200 rpm, and the ball milling time is from 1 h to 30 h.

6. The method of claim 1 , wherein the separating and purifying comprise dissolving the ball-milled mixtures in a solvent, filtering for removing insoluble residues, and evaporating the obtained clear filtrate under high vacuum;
wherein the solvent is diethyl ether which is distilled over Na.

Assignees

• Univ South China Tech

Inventors

• Ouyang Liuzhang
• Chen Kang
• Wang Hui
• Liu Jiangwen
• Zhu Min

Classifications

• C01B6/17 Primary

  Preparation from boron or inorganic compounds containing boron and oxygen · CPC title

• C01P2002/74

  by peak-intensities or a ratio thereof only · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title

• C01P2006/80

  Compositional purity · 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