Method for producing high-solubility ammonium heptamolybdate

An ammonium heptamolybdate, high solubility technology, applied in chemical instruments and methods, molybdenum compounds, inorganic chemistry, etc., can solve problems such as ammonia pollution, and achieve the effect of avoiding the crushing process, reducing process steps, and ensuring quality

Active Publication Date: 2014-08-27
JIANGSU DONGTAI FENGFENG TUNGSTEN & MOLYBDENUM MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Problems to be solved by the present invention: 1. Solve the problem of ammonia pollution in the production process of ammonium heptamolybdate; 2. Improve the quality of ammonium heptamolybdate so that it meets the requirement of high solubility (80g) in the petrochemical field

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] In a closed reaction kettle, put 10L of 15% ammonia water and 8Kg of ammonium tetramolybdate, heat it to 80°C with a heating furnace, and the air pressure is 1300 hPa, dissolve ammonium tetramolybdate, and control by adding ammonia water and / or pure water The pH value was 6, and the stirring speed was 50 rpm for 15 minutes. Then filter, cool the filtered filtrate in a water bath at 20°C, and then carry out high-speed centrifugal dehydration after cooling to 20°C to obtain granular ammonium heptamolybdate crystals, and then put the granular ammonium heptamolybdate crystals into a drying room for 40 After drying with hot air at ℃ for 2.5 hours, 6473 g of ammonium heptamolybdate was obtained, with a comprehensive crystallization rate of 81%. The analytical chemical indicators conform to GB657-79, and the solubility is 82g. After dissolving in water, the transparency can reach 95% of pure water.

Embodiment 2

[0021] In a closed reaction kettle, put 10L of 14% ammonia water and 8Kg of ammonium dimolybdate, heat it to 75°C with a heating furnace, and the air pressure is 1100 hPa, dissolve ammonium tetramolybdate, and control by adding ammonia water and / or pure water The pH value was 5, and the stirring speed was 60 rpm for 18 minutes. Then filter, cool the filtered filtrate in a water bath at 18°C, and carry out high-speed centrifugal dehydration after cooling to 18°C ​​to obtain granular ammonium heptamolybdate crystals, then put the granular ammonium heptamolybdate crystals into the drying room, 60 After drying with hot air at ℃ for 1.5h, 6145g of ammonium heptamolybdate was obtained, with a comprehensive crystallization rate of 76%. The analytical chemical index conforms to GB657-79, and the solubility is 80g. After dissolving in water, the transparency can reach 93% of pure water.

Embodiment 3

[0023] In a closed reactor, put 8L of 20% ammonia water, 8Kg of ammonium tetramolybdate, 2L of pure water, heat to 85°C with a heating furnace, and the air pressure is 1500 hPa, dissolve ammonium tetramolybdate, and add ammonia and / or Pure water, control the pH value to 5.5, and stir for 12min under the condition of stirring speed of 55rpm. Then filter, cool the filtered filtrate in a water bath at 19°C, and carry out high-speed centrifugal dehydration after cooling to 19°C to obtain granular ammonium heptamolybdate crystals, and then put the granular ammonium heptamolybdate crystals into the drying room for 50 After drying with hot air at ℃ for 2 hours, 6272 g of ammonium heptamolybdate was obtained, with a comprehensive crystallization rate of 77%. The analytical chemical indicators conform to GB657-79, and the solubility is 81g. After dissolving in water, the transparency can reach 94% of pure water.

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PUM

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Abstract

The invention discloses a method for producing high-solubility ammonium heptamolybdate. The method comprises the following steps of: in a sealed reaction kettle, dissolving ammonium tetramolybdate or ammonium dimolybdate in ammonia water with concentration of 14%-16%, and applying a certain gas pressure during dissolving; then, filtering and cooling liquor, carrying out high-speed centrifugal dehydration while cooling to 18-20 DEG C to obtain granulate ammonium heptamolybdate crystals; finally, drying. Compared with the existing production technology, environmental pollution is reduced as the method is carried out in the sealed reaction kettle; during dissolving, quality of ammonium heptamolybdate is improved by applying a certain pressure, so that produced ammonium heptamolybdate has solubility of over 80g. Meanwhile, when ammonium heptamolybdate is dissolved in water, light transmittance can reach 95% that of the pure water. Finally, ammonium heptamolybdate produced by the method disclosed by the invention does not need a crushing step, so that production efficiency is improved.

Description

technical field [0001] The invention relates to a production process of ammonium heptamolybdate. Background technique [0002] Ammonium heptamolybdate (ammonium paramolybdate) is a kind of molybdate product series, molecular formula (NH 4 ) 6 MO 7 o 24 4H 2 O, is a white or greenish crystalline powder. Insoluble in ethanol, the solubility in water at room temperature is generally above 40g. When the ammonium heptamolybdate produced by the general process is used as a reagent, the national standard is fully applicable, but as a raw material for acrylonitrile catalyst in the petrochemical field, the high resolution index cannot meet the product requirements. [0003] The classic method commonly used in the production of ammonium heptamolybdate is to add the ammonium of the present invention through a certain concentration of ammonia water, the temperature is 75 ° C ~ 85 ° C, and the pH value is 5.0 ~ 6.0. After filtration and separation, the clarified ammonium molybdate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G39/00
Inventor 吴勇本龚振宇徐志贤周圣安谢付根
Owner JIANGSU DONGTAI FENGFENG TUNGSTEN & MOLYBDENUM MATERIAL
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