Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon

A sodium thiosulfate and sodium sulfide technology, applied in the direction of alkali metal sulfide/polysulfide, etc., can solve the problems of large equipment investment, difficult process control, and large carbon consumption, so as to reduce production costs, reduce environmental pollution, The effect of eliminating environmental pollution

Active Publication Date: 2005-01-05
ANHUI XUELANG BIOTECHNOLOGY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, it is necessary to strictly control the amount of air supply. If too much oxygen is supplied, the carbon will be excessively burned and the carbon consumption will be too large. If too little oxygen is supplied, the temperature will be insufficient, the reduction reaction will not occur, and the process control will be difficult.
In addition, the reaction speed is slow, the equipment investment is large, the cost is high, and the production efficiency is low, which is not conducive to industrialized production

Method used

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  • Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon
  • Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon
  • Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon

Examples

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Effect test

Embodiment 1

[0021] Embodiment 1: Sodium thiosulfate 50g, charcoal powder 20g are mixed homogeneously, are placed in the crucible, add a cover, only leave air hole, in case contact with air and burn. Put it into a microwave oven with an input power of 1000W and a microwave frequency of 2450MHz, and induce heating in the microwave cavity for 3 minutes. It was found that besides the formation of sodium sulfide, sulfur was also generated. The transformation rate of sodium thiosulfate is greater than 95%, and a small amount of sodium sulfate is also generated.

Embodiment 2

[0022] Example 2: Mix 50 g of sodium thiosulfate, 25 g of sodium hydroxide, and 20 g of charcoal powder evenly, put them in a crucible, place them in a 1000W, 2450 MHz microwave oven, heat for 3 minutes, and the reduction reaction can be completed. The conversion rate of sodium thiosulfate is greater than 98%, and no sulfur and sodium sulfate exist. The reaction mixture was dissolved in 100 ml of water, and excess carbon was removed by filtration to obtain a light yellow transparent liquid with a sodium sulfide content of 32%.

Embodiment 3

[0023] Example 3: Mix 50 g of sodium sulfate and 20 g of charcoal powder evenly, put them in a crucible, place them in a 1000W, 2450 MHz microwave oven, heat for 5 minutes, and the reduction reaction ends. The transformation rate of sodium thiosulfate is greater than more than 96%, and is processed by the method for example 2, obtains almost colorless and transparent sodium sulfide, content 15%.

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Abstract

The invention discloses a method of preparing sodium sulphide by using microwave induced carbon to reduce sodium thiosulfate, and its characteristic: in mole ratio of sodium thiosulfate to alkali 1 to 2, mixing sodium thiosulfate with excessive carbon for concentrating or spray-drying, using microwave to act on the obtained solid for 2-3 min and completing the reaction, after cooling, adding in water for dissolving, filtering and recovering the fully unreacted carbon, and the filtrate is sodium sulphide solution. It can economically and fast reduce the waste liquids containing sodium thiosulfates into sodium sulphides, and the produced sodium sulphides contain no organic impurities and can meet the requirement of circularly using.

Description

technical field [0001] The invention provides a method for reducing sodium thiosulfate to sodium sulfide with carbon under the action of microwaves. The method has high speed and low energy consumption, and can be widely used to recycle waste liquid containing sodium thiosulfate, thereby reducing production cost and environmental pollution. Background technique [0002] Sodium sulfide is a widely used reducing agent, usually used to reduce nitro compounds to amine compounds, especially for the reduction of aromatic nitro compounds to prepare aromatic amine compounds. It is usually prepared by absorbing hydrogen sulfide with alkali, or reducing sodium sulfate with carbon. The former is not widely used due to the limitation of the source and purity of hydrogen sulfide; while the latter is widely used in industrial production due to the easy availability of sodium sulfate and carbon raw materials, low price and good product quality. As shown in the following formula: [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/26
Inventor 李云政
Owner ANHUI XUELANG BIOTECHNOLOGY CO LTD
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