Safety research on fully enclosed filter washing and drying machine for refining and purifying rubber accelerator m by solvent method

2023/04/07

Rubber vulcanization accelerator M, the full name of rubber vulcanization accelerator 2-mercaptobenzothiazole, is a general-purpose accelerator, widely used in various rubbers, and has rapid vulcanization acceleration in natural rubber and general synthetic rubber. In addition, it also has certain plasticizing and anti-aging properties, and can be used as a retarder in chloroprene rubber. With the rapid development of my country's automobile and tire industries, the demand for rubber vulcanization accelerators and their derivatives has been stimulated and stimulated.


At present, the production process of rubber accelerator M at home and abroad will produce a considerable amount of "three wastes". It is no exaggeration to say that the environmental pollution problem in the production process of rubber accelerator M has become the main bottleneck restricting its development. Therefore, how to develop Relatively clean process technology, while strengthening the treatment and recycling of the "three wastes" generated in the current production process, has become a hot topic in the rubber additives industry
At present, domestic production enterprises mainly adopt the aniline method, which uses aniline as raw material to react with carbon disulfide and sulfur, which is divided into high-pressure method and normal-pressure method. Because the high-pressure method can realize continuous production, and the cost is low, it is favored in the industry. In recent years, most of the domestic production has chosen the high-pressure method.

The high-pressure aniline method is to synthesize the three raw materials of aniline, CS2 and sulfur under high temperature and high pressure, and then undergo a series of post-treatment separation and purification to obtain the rubber accelerator M. Its classic process is as follows:
(1) First, aniline and CS2 are dissolved at 220-280C and 8.0-10.0MPa to react to obtain the crude product M;
(2) Then through a series of separation processes such as alkali dissolution, oxidation, filtration, acidification, dehydration, and drying to obtain the fine product M;
(3) According to different post-treatments, it can be divided into acid-base method and solvent method.
The high-pressure aniline production process has stable conditions, low cost, and high product quality, but there are still high raw material consumption and high intermittent production costs.

The whole reaction process is performed intermittently, and the degree of continuous mechanization is low. Finally, the accelerator M and the solvent are removed or extracted by a centrifuge, solid-liquid separation, and drying are completed in multiple independent equipment. The operation is cumbersome and labor-intensive. Large quantity, poor operating environment, unstable product quality and other disadvantages. Furthermore, the use of centrifuges in the presence of organic solvents increases safety risks. At the same time, there is a lot of wastewater discharge, high electricity load, high-pressure synthetic waste gas H2S and excess CS2 are not recycled, and the discharged hydrogen sulfide is seriously polluted.

Therefore, further improving the yield of products, reducing costs, saving energy and reducing emissions have become urgent problems to be solved.



The new refining process of rubber vulcanization accelerator M fully utilizes raw materials, has low cost, simple process, energy saving and environmental protection. The process steps of the fully enclosed filter washing and drying machine are as follows:
(1) Add the crude rubber vulcanization accelerator M sodium salt solution into the reaction kettle, add water to control the sodium salt mass concentration at 55-65%, add dilute sulfuric acid dropwise, and neutralize the pH of the solution to 7-10;
(2) Add extractant to the solution obtained in the previous process, then feed pure oxygen, the reaction temperature is controlled at 40-50°C, and the extractant is a mixed solution of water, 27.5wt% hydrogen peroxide and 93wt% sulfuric acid;
(3) Add dilute sulfuric acid to the solution obtained in step (2), adjust the pH value to 5-9, and the stirring motor speed of the three-in-one reactor is 50-60r/min;
(4) Then use the fully-closed cylinder-cone three-in-one filter washing and drying machine to first settle and wash, then filter, wash and dry again.

After the post-treatment process, the high-quality rubber vulcanization accelerator M is obtained.



Solvent method rubber accelerator m refining and purification, fully enclosed filter washing and drying machine Technical advantages:
(1) The new refining method makes full use of raw materials, low cost, energy saving and environmental protection, simple and easy process, and convenient for large-scale industrial production;
Pure oxygen is passed into the crude M sodium salt, and pure oxygen can catalyze the intermediate product benzothiazole and anilinobenzothiazole in the crude M sodium salt to continue to react with sulfur to generate M, thereby increasing the M content in the crude M, the method The raw materials are fully utilized and the cost is saved.
(2) High-quality rubber promotes M, bright in color, 0.5-1.5% higher in purity than the prior art, 2-4% higher in yield, 1-1.5 h shorter in oxidation time, and 200-400 yuan/ton lower in cost.




Solvent method rubber accelerator m refining and purification, fully enclosed filter washing and drying machine
(1)- The machine is multi-purpose, and can complete various operations such as reaction, extraction, filtration, repeated filtration, washing, and drying in one machine, and the finished product can be obtained directly.
(2) The operating flexibility is large, and the operating cycle can be adjusted by adjusting the filter pressure difference, rotating speed, screw extrusion lead, etc., so as to adapt to the change of I process conditions.
(3) The machine can form a very thin filter cake on the surface of the filter medium or filter under the condition of no filter cake. The filtration rate per unit filtration area is very high, so the equipment is small and compact.


(4) Fully enclosed system with a good operating environment, especially suitable for handling toxic, flammable and explosive dangerous products and delicious food, biological products and pharmaceuticals that do not allow pollution.
(5) It can be concentrated and filtered. Especially when it is necessary to wash the material, the material can be concentrated first, washed thoroughly in suspension, and finally press-filtered.
This can reduce the handling of materials, reduce waste, do not need to re-pulp when washing, and the processed products are of high quality.


(6) It can be used for three operations of reaction, filtration, and drying, so that the functions of the three unit equipment can be completed on this one equipment, so that the equipment cost, floor space, labor intensity, and energy consumption can be reduced.
etc. are greatly reduced.
(7) The power consumption of this machine is low, and the extruded filter cake generally has lower water content than the flat-type three-in-one, and the operation is also convenient.





Solvent-method rubber accelerator m refining and purification, fully enclosed filter washing and drying integrated machine realizes the mechanization and automation of the solvent-method purified rubber vulcanization accelerator production line, effectively solves solvent volatilization, reduces production energy consumption, has safe operating environment, low labor intensity, and low operating costs low merit.

Aiming at the problem that the acid-base purification process will generate a large amount of wastewater, the fully enclosed cylinder-cone three-in-one filter washing and drying machine developed and produced by Wuxi ZhangHua Machinery Co., Ltd. can greatly reduce the amount of wastewater.



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