How to prepare ammonium metatungstate? The researchers have proposed a preparation method of ammonium metatungstate - mainly used as a catalyst for petroleum cracking.
More details, please visit:
http://www.ammonium-metatungstate.com/index.html
A Preparation Method of Ammonium Metatungstate
Step One: Dissociation. 100kg of APT is heated and calcined in the rotary furnace at a temperature of 180°C for 50 min to prepare a dissociated material. At the same time, the inlet of the rotary furnace was fed with rare gas helium gas, the flow rate is 200 sccm.
Step Two: Leaching. Send the dissociated material to the reaction kettle, add 1 mol/L of dilute nitric acid for reaction, control the pH value to 3-5, and when the WO3 content in the solution reaches 150 g/L, stir for 10-20min to obtain AMT solution.
Step Three: Clarification and filtration. AMT solution was allowed to stand and age for 1 h in the first clarification tank, and then the clarified solution was filtered with a first bag filter to obtain filtrate A.
Step Four: Concentration, clarification and filtration. Filtrate A is heated and concentrated in the concentration reactor. The concentration temperature is 60°C. The pH value of the filtrate A is adjusted with ammonia water to 3-4. When the specific gravity of the filtrate A reaches 1.6, the filtrate A is sent to the second clarification tank, let stand and age for 2h, and then filter the clarified solution with a second bag filter to obtain filtrate B.
Step Five: Spray drying. Filtrate B was spray dried by a spray drying tower to obtain ammonium metatungstate. Wherein, inlet air temperature is 180 °C, outlet air temperature is 110 °C, and feed rate is100 kg/h. And 4kg of diatomaceous earth is placed on the bottom of the first clarification tank in Step Three and the second clarification tank in Step Four, respectively.
