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A kind of preparation method of low-nitrogen high-purity calcium hydride

A pure calcium hydride, high-purity technology, applied in chemical instruments and methods, alkali metal/alkaline earth metal/beryllium/magnesium hydride, hydrogen, etc. Calcium hydride low purity and other issues, to prevent melting or even evaporation, fine particle size, reduce the effect of impurity content

Active Publication Date: 2019-03-22
有研资源环境技术研究院(北京)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the purity of calcium hydride at home and abroad is low, especially the content of gas impurities is high, the content of oxygen is as high as 0.6%, and the content of nitrogen is as low as 1000ppm. The quality of existing calcium hydride cannot meet the requirements of hydrogen fuel cells. Some technologies have their own problems:
[0005] (1) During the hydrogenation process, the reaction of calcium and hydrogen is almost instantaneous, and within 1 to 2 minutes, it can absorb 60% to 80% of the hydrogen in the entire reactor. It will become a vacuum with a residual pressure of only a few millimeters of mercury. If the equipment is not well sealed, it will absorb a large amount of air, which will not only affect the quality of the product, increase the nitrogen content, but also easily cause explosion hazards.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Put a stainless steel crucible with 99% purity and a size of 3cm×3cm high-purity calcium into the furnace, and evacuate to 10 - 3 Pa, washed with high-purity hydrogen for 3 times, filled with hydrogen to a slight positive pressure (0.2MPa), heated to 300°C at a rate of 3°C / min and kept at a constant temperature for 0.5 hours, and then hydrogenated (flow rate 0.1L / min) for hydrogenation For 0.5 hours, keep the hydrogen at a slight positive pressure (0.2MPa); raise the temperature to 500°C at a rate of 3°C / min, keep the temperature constant for 0.5 hours, and pass in hydrogen (flow rate 0.1L / min) for hydrogenation for 0.5 hours. Cool to room temperature in hydrogen, crush and sieve the obtained product after being released from the furnace, the nitrogen content in the prepared calcium hydride is 98ppm, the oxygen content is 0.4%, and the metal impurities Fe, Ni, Cu content are respectively 180ppm, 150ppm, 100ppm, particle size is 200 mesh.

Embodiment 2

[0024] Put a stainless steel crucible containing high-purity calcium with a purity of 99.2% and a size of 2cm×3cm into the furnace, and evacuate to 10 -3 Pa, washed with high-purity hydrogen for 3 times, filled with hydrogen to a slight positive pressure (0.3MPa), heated to 350°C at a rate of 4°C / min and kept at a constant temperature for 1 hour, and then hydrogenated (flow rate 0.2L / min) for 1 hour, keep the hydrogen pressure at slightly positive pressure (0.3MPa); raise the temperature to 450°C at a rate of 4°C / min and keep the temperature constant for 1 hour, feed hydrogen (flow rate 0.2L / min) for hydrogenation for 1 hour, and keep the hydrogen pressure at slight Positive pressure (0.3MPa); heat up to 550°C for another 2 hours, pass in hydrogen (flow rate 0.2L / min) for hydrogenation for 1 hour, and keep the hydrogen pressure at slightly positive pressure (0.3MPa). Cool to room temperature in hydrogen, crush and sieve the obtained product after coming out of the furnace, the...

Embodiment 3

[0026] Put a stainless steel crucible containing high-purity calcium with a purity of 99.5% and a size of 2cm×2cm into the furnace, and evacuate to 10 -3 Pa, clean with high-purity hydrogen for 3 times, fill with hydrogen to slightly positive pressure (0.5MPa), raise the temperature to 400°C at a rate of 5°C / min and keep the temperature constant for 2 hours, then pass in hydrogen (flow rate 0.5L / min) for hydrogenation 2 hour, keep the hydrogen pressure at a slight positive pressure (0.5MPa); raise the temperature to 550°C at a rate of 5°C / min and keep the temperature constant for 2 hours, feed hydrogen (flow rate 0.5L / min) for hydrogenation for 2 hours, and keep the hydrogen pressure at a slight Positive pressure (0.5MPa). Cool to room temperature in hydrogen, crush and sieve the obtained product after being released from the furnace, the nitrogen content of the prepared calcium hydride powder is 80ppm, the oxygen content is 0.35%, and the metal impurities Fe, Ni, Cu content a...

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Abstract

The invention discloses a preparation method of low-nitrogen and high-purity calcium hydride and belongs to the field of preparation of hydrogen storage and supply materials. A stainless steel crucible containing high-purity block calcium is put in a furnace, subjected to vacuum pumping after being covered with a lid, inflated with high-purity hydrogen for washing and then inflated with hydrogen till the micro-positive pressure state after washing, heating and hydrogenation are performed, a plurality of constant-temperature platforms are arranged, block calcium is cooled to the room temperature after hydrogenation is completed, a product is crushed and sieved, a calcium hydride product with the granularity of 200 meshes is obtained, wherein the nitrogen content is smaller than 100 ppm, the oxygen content is smaller than 0.4%, and the content of metal impurities including Fe, Ni and Cu is smaller than 200 ppm. The method has the advantage of slow hydrogen absorption, and the condition that calcium hydrogenation is hindered by violent reactions and metal calcium sintering is avoided; the content of nitrogen in calcium hydride is reduced, calcium hydride is high in purity and easy to crush, a technology is safe and controllable, and explosion is prevented.

Description

technical field [0001] The invention belongs to the field of preparation of hydrogen storage and hydrogen supply materials, and in particular relates to a preparation method of low-nitrogen high-purity calcium hydride. Background technique [0002] The development of new energy has brought about the rise of the battery field. ROHM hydrogen fuel cells have more exclusive advantages in the battery field. It overcomes the weaknesses of batteries such as dry batteries and lithium-ion batteries, and achieves a significant reduction in weight, high power and high safety. At the same time The convenience of the power supply has been improved, and it can be used as a portable power supply such as a smartphone. [0003] Calcium hydride is used as a hydrogen storage and hydrogen supply material for Rohm hydrogen fuel cells. It has the characteristics of a theoretical hydrogen desorption rate of >9wt%, a working temperature below 100°C, and a fast hydrogen absorption and desorption ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B6/04C01B3/00H01M4/88
CPCC01B3/001C01B6/04C01P2006/80H01M4/88Y02E60/32Y02E60/50
Inventor 王芳黄永章王力军薛红霞李婷赵若岐
Owner 有研资源环境技术研究院(北京)有限公司