Abstract
The purpose of this article is to explain the process of obtaining ammonium molybdate from ammonium molybdate in a systematic way. In the experiments, 3 methods were adopted to test the reactivity of ammonium molybdate. Firstly, the precipitation method, which is composed of the simultaneous precipitation of ammonium molybdate in concentrate ammonium nitrate solution. Secondly, the extraction method, which uses an organic solvent as an extracting medium and obtains the product of ammonium molybdate. Last but not least, the combination of the two methods, that is, the solubilization of ammonium molybdate in concentrated ammonium nitrate solution and the extraction of it in organic solvent. The concomitant degree and yield of the products obtained by the three methods were compared and analyzed. Generally, the combination of precipitation and extraction method is preferred to obtain ammonium molybdate. Also, the optimum parameters are discussed.
Introduction
Ammonium molybdate (AM) is widely used in industrial production, such as dyes, mordants, pharmaceutical intermediates and water treatment agents. The yield of ammonium molybdate mainly depends on the production technology. Ammonium molybdate can be synthesized by the solvothermal method, but the reaction time is generally long and the reaction conditions are difficult to control.Therefore, the synthesis of ammonium molybdate via extraction method is recently used to obtain high-yield ammonium molybdate.
Materials and Methods
The experiment materials include ammonium nitrate, ammonium molybdate, organic solvents and distilled water. The reaction conditions of the three methods used in the experiment are listed in Table 1.
Table 1. Reaction Conditions of Three Methods
Method Temperature/℃ Solvent Time/min Precipitation 65 Concentrated ammoniumnitrate solution 90 Extraction 60 Ethanol 180 Combination 65 (40％Concentrated Ammoniumnitrate solution，60％Ethanol ) 150
Results and Discussion
1. Analysis of Ammonium Molybdate Product Yield
The yield of the products from three methods was compared. The recovery yield of ammonium molybdate is shown in Table 2.
Table 2. The Recovery Yield of Ammonium Molybdate (%w/w).
Method Yield Ammonium molybdate (%) Precipitation 75.4 Extraction 82.5 Combination 100.0
It can be seen from Table 2 that the yield of ammonium molybdate from the precipitation method is 75.4%. The yield is lower than that of extraction method, which is 82.5%. The combination of precipitation method and extraction method has the highest recovery rate of ammonium molybdate, which was 100% in this experiment.
2. Analysis of Ammonium Molybdate Quality
The quality of ammonium molybdate is analyzed by X-ray fluorescence. The content of ammonium molybdate in the three products is shown in Table 3.
Table 3. The Content of Ammonium Molybdate in Products(%)
Method Content of Ammonium molybdate (%) Precipitation 80.2 Extraction 78.5 Combination 81.3
The results show that the quality of the product obtained from precipitation method is higher than that from extraction method, with the highest content of ammonium molybdate being the product obtained from combination method.
Conclusion
In this experiment, three methods were adopted to obtain ammonium molybdate. The experiment results show that the combination of precipitation and extraction method has high yield and product quality. The optimum parameter of this method is 40% ammonium nitrate aqueous solution and 60% ethanol as extraction medium, reaction temperature of 65℃, and reaction time of 150min.
