Dicyandiamide production method

A production method, dicyandiamide technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of easy explosion of calcium carbide, large amount of residue and dust, high safety requirements, etc., and achieve production cost The effect of reducing and reducing environmental pressure and improving safety

Inactive Publication Date: 2012-01-18
宁夏北极星化工有限公司
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Problems solved by technology

Due to the high energy consumption and large amount of residue and dust in the production process of calcium carbide, the production cost is high and the pressure on environmental protection is high, and calcium carbide is prone to explosion during production and transportation, and the safety requirements in the production and transportation process are high, and the product is effective. Nitrogen content around 19-23%

Method used

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  • Dicyandiamide production method
  • Dicyandiamide production method
  • Dicyandiamide production method

Examples

Experimental program
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Effect test

Embodiment 1

[0021] Such as figure 1 As shown, the lime is now crushed to 20 meshes, mixed evenly according to the weight ratio of urea:lime 1:1, put into the calciner, and heated to about 200-240°C under the protection of nitrogen for calcination for 2 hours, and then heated up After calcining at 650-700°C for 3 hours, a compound mainly containing calcium cyanamide is obtained. The obtained compound mainly containing calcium cyanamide is reacted according to the existing calcium cyanamide hydrolysis and polymerization methods to obtain dicyandiamide. At this time, the effective nitrogen content in the intermediate product calcium cyanamide can reach more than 23%.

Embodiment 2-3

[0023] On the basis of embodiment 1, change the relevant process parameters as follows:

[0024]

[0025] The effective nitrogen content in the intermediate product calcium cyanamide obtained in the above-mentioned embodiment 2 can reach more than 23.5%.

[0026] The effective nitrogen content in the intermediate product calcium cyanamide obtained in the above-mentioned embodiment 3 can reach more than 25%.

[0027] In the above examples 1-3, after recovering the tail gas generated in the calcination process, the tail gas mainly contains ammonia, carbon dioxide and nitrogen that does not participate in the reaction and plays a protective role. The above tail gas is passed through an ammonia absorption tower sprayed with hydrochloric acid to obtain an ammonium chloride solution. Add the obtained calcium cyanamide into the hydrolysis tank, and then pass through the carbon dioxide collected after passing through the ammonia absorption tower, and the nitrogen that does not par...

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Abstract

The invention relates to a dicyandiamide production method, which comprises the process steps of pulverization, mixing, calcining, hydrolysis, polymerization and dicyandiamide obtaining. The dicyandiamide production method has the following characteristics that: because the urea used as chemical fertilizers in the prior art and lime with wide sources are used as raw materials, on one hand, the production cost is reduced, on the other hand, the safety in the production process is improved, the process condition in the whole production process is simple, very good use prospects are realized, the tail gas is recovered in the calcining process, the cyclic utilization is realized, the environment protection pressure is reduced, and economic benefits are improved. In the calcining process, the tail gas sequentially passes through an ammonia absorbing tower and a calcium cyanamide hydrolysis pool, and calcium carbonate can be produced. The rest nitrogen gas can be directly returned to a calcining furnace for being reused after the drying treatment, and the efficient nitrogen content of the calcium cyanamide produced by the process can reach 23 percent to 25 percent and is higher than the efficient nitrogen content of the calcium cyanamide produced by a calcium carbide process.

Description

technical field [0001] The present invention relates to the production method of dicyandiamide. Background technique [0002] At present, the production of dicyandiamide in China adopts the process route of calcium carbide and nitrogen reacting under heating conditions to generate lime nitrogen, followed by hydrolysis and polymerization to obtain dicyandiamide. Due to the high energy consumption and large amount of residue and dust in the production process of calcium carbide, the production cost is high and the pressure on environmental protection is high, and calcium carbide is prone to explosion during production and transportation, and the safety requirements in the production and transportation process are high, and the product is effective. The nitrogen content is around 19-23%. Contents of the invention [0003] The purpose of the present invention is to overcome the defects in the above-mentioned prior art and provide a production method of dicyandiamide with low ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C279/28C07C277/08
Inventor 高靖国赵黎明
Owner 宁夏北极星化工有限公司
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