Method for preparing superfine cobalt powder in close-packed hexagonal structure or face-centered cubic structure by hydrogen reduction

A technology of ultra-fine cobalt powder and close-packed hexagonal, applied in the field of metal powder material preparation, can solve the problems of high equipment requirements, large operational hidden dangers, difficult industrialization implementation, etc., and achieves mild reaction conditions, low equipment requirements, and low operation difficulty. Effect

Inactive Publication Date: 2010-02-24
KUNMING INST OF PRECIOUS METALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The ultra-fine cobalt powder prepared by this method has a finer particle size and a single close-packed hexagonal crystal form, but the hydrogen pressure required by this method is relatively high (>2MPa), the requirements for equipment are too high, and there are great hidden dangers in operation, so it is difficult to industrialize implement
And because the particle size of cobalt powder is too fine and its oxidizing property is extremely strong, the purity can only reach about 95% in the case of vacuum drying, so it is difficult to meet the requirements of ultrafine cobalt powder products

Method used

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  • Method for preparing superfine cobalt powder in close-packed hexagonal structure or face-centered cubic structure by hydrogen reduction
  • Method for preparing superfine cobalt powder in close-packed hexagonal structure or face-centered cubic structure by hydrogen reduction
  • Method for preparing superfine cobalt powder in close-packed hexagonal structure or face-centered cubic structure by hydrogen reduction

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Cobalt sulfate heptahydrate was used as raw material and sodium hydroxide as precipitant to prepare superfine cobalt powder with single hexagonal close-packed structure. Add 200L of deionized water to the pre-reactor A, weigh 37.5kg of industrial pure sodium hydroxide, add it and stir to dissolve the sodium hydroxide; add 400L of deionized water to the pre-reactor B, weigh industrial pure heptahydrate sulfuric acid Cobalt 125kg, add wherein and fully stir to make cobalt sulfate dissolve; The lye in the pre-reactor A is pumped in the pre-reactor B, fully stirred to make it react completely, add the palladium chloride aqueous solution that configures (containing palladium chloride 12.5 g) 5L, stir evenly; pump the sediment water slurry reacted in the pre-reactor B into 3 Fill the reactor with nitrogen to discharge the air in the reactor, then empty it, fill it with hydrogen at 0.4MPa, heat it to 160°C and then fill it with hydrogen to keep the hydrogen partial pressure at...

Embodiment 2

[0028] Cobalt sulfate heptahydrate was used as raw material and sodium hydroxide as precipitant to prepare superfine cobalt powder with single face-centered cubic structure. Add 200L of deionized water to the pre-reactor A, weigh 37.5kg of industrial pure sodium hydroxide, add it and stir to dissolve the sodium hydroxide; add 400L of deionized water to the pre-reactor B, weigh industrial pure heptahydrate sulfuric acid Cobalt 125kg, add wherein and fully stir to make cobalt sulfate dissolve; The lye in the pre-reactor A is pumped in the pre-reactor B, fully stirred to make it react completely, add the palladium chloride aqueous solution (containing palladium chloride 20g )5L, stir evenly; pump the sediment water slurry reacted in the pre-reactor B into 3Fill the reactor with nitrogen to discharge the air in the reactor, then empty it, fill it with hydrogen at 0.4MPa, heat it to 150°C and then fill it with hydrogen to keep the hydrogen partial pressure at 0.9MPa, control the st...

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Abstract

The invention discloses a technical method for preparing superfine cobalt powder in a close-packed hexagonal structure or a face-centered cubic structure by hydrogen reduction, and belongs to the technical field of the preparation of metal powdered material. The invention comprises the following steps: excessive alkali is added into the water soluble salt of cobalt which is used as a raw material,obtained precipitation of hydroxide of the cobalt is directly transferred into a high-pressure autoclave without filtration and reduced under the catalysis of a small quantity of palladium chloride below 180 DEG C in poor hydrogen (<1MPa), the reduzate is reduced by secondary consolidation hydrogen in a hydrogen reducing furnace after being filtered, washed and dried and then crashed under the protection of inert gas, and finally, the superfine cobalt powder which has the granularity of less than 0.5um, big specific surface, even distribution and single close-packed hexagonal structure or face-centered cubic structure is produced.

Description

technical field [0001] The invention belongs to the technical field of metal powder material preparation, and in particular provides a combination of high-pressure hydrogen reduction and high-temperature solid-phase hydrogen reduction to prepare ultrafine spherical cobalt powder with a single hexagonal close-packed structure or a face-centered cubic structure. Background technique [0002] Ultra-fine cobalt powders, especially nano-scale cobalt powders, exhibit large surface effects, volume effects, and dielectric effects due to the relatively small number of atoms contained in them. These effects make ultra-fine cobalt powder have very different electrical properties, magnetic properties, mechanical properties, optical properties and structural properties, etc. , luminescent materials, ceramics and other fields have been widely researched and applied. [0003] In terms of cemented carbide, the cemented carbide using ultra-fine cobalt powder not only reduces the porosity an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/26
Inventor 汪云华昝林寒赵家春范兴祥吴晓峰李柏榆吴跃东
Owner KUNMING INST OF PRECIOUS METALS
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