Tungsten Smelting Liquid Ammonia Recycling and Utilization

The most common method for the production of ammonium para tungstate in tungsten smelting is ion exchange. Ammonium chloride is used as a desorption agent in almost all kinds of tungsten smelting. In order to prevent the production of ammonium para tungstate crystal during the process of desorption, a proper amount of ammonia water must be added to the desorption agent. Therefore, liquid ammonia is a necessary auxiliary material.

Liquid ammonia is usually stored in steel cylinders or steel tanks. The state laws and regulations have clearly stipulated that the critical capacity of liquid ammonia up to 10 tons is a major hazard source. On the one hand, the liquid ammonia storage device will increase the internal pressure in the case of fire or heat, and the risk of cracking and explosion will occur. On the other hand, the mixture of ammonia and air will form an explosive mixture. Once the leakage occurs, it is not only inconvenient to recover, but will also seriously pollute the environment, and will cause great harm to the surrounding people.

Researchers have created a method for the recycling of ammonia in a process of producing ammonium partrungstate.

In the process of producing ammonium para tungstate, the discharge port of the furnace in the process of producing the yellow blue tungsten process is parallel, and the ammonia gas produced in the two device is sent into the distillation column to separate the initial gas-liquid, and the initial gas liquid separation is retransmitted into the condensing system for a thorough gas-liquid separation, and then the ammonia gas is obtained. 73% of the ammonia gas is transmitted to the spray adsorption tower, and the ammonia is spray adsorbed with hydrochloric acid. The concentration of hydrochloric acid in the spray adsorption is used 1.35mol/L, and the ammonium chloride solution is obtained. The solution is collected in the container I and then the ammonium chloride solution in the container I is pumped into the Venturi device high 20.5M from the ground. The 27% of the residual gas is transmitted to the Venturi device, which causes the ammonium chloride solution to form a vacuum from top to bottom, dissolves ammonia in the ammonium chloride solution, and obtains a mixed solution of ammonia and ammonium chloride, and also is collected in the container I, and the mixed solution inside the container I is cooled to 10°C to ensure that the ammonia is non volatile. In order to realize the absorption of ammonia in a continuous cycle, the concentration requirement of the desorption agent needed in the process of production of ammonium para tungstate was required, and then the ammonia gas produced during the production of ammonium para tungstate was recycled.

The above method is both safe and environmental, and the input is less efficient and can completely recycle the ammonia emitted from the production process of ammonium para tungstate, thus achieving zero storage and zero consumption of liquid ammonia. 

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