In order to solve the problem of determination of boron in ammonium paratungstate(APT), the authors began with the study on determination way by ICP AES. The matrix effect and spectral interference of tungsten on boron in ICP AES were studied. The effects of acidity, time of boiling and time of putting aside were investigated. Combining with matrix seperation and factor correction, a new simple,rapid and accurate method for determination of B in APT was developed. The recovery is higher than 95.8%; the relative standard deviation of determination of 0.000 x %～0.00 x %B in APT is lower than 3%. The accuracy and precision of the method are satisfactory.

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The bulk structural evolution during the decomposition of ammonium paratungstate (APT) under various oxidizing and reducing gases was elucidated by the complementary techniques, in situ XAS, in situ XRD, and TG/DSC, combined with mass spectrometry. In the temperature range from 300 to 650 K, the decomposition of APT proceeds nearly independently of the gas employed. At higher temperatures, an oxidizing gas results in the formation of crystalline triclinic WO3 as the majority phase at

Coarse and spherical tungsten powders were prepared by wet hydrogen reduction.Ammonium tungstate solutions with the additives of Li,Na and K alkali metal salts were used as raw materials.The effects of the type and content of the alkali metal salts as well as reduction time on the microstructure,chemical composition,phase composition, and particle size of ammonium paratungstate(APT) and coarse tungsten powders were investigated by scanning electronic microscopy,energy dispersive

In this research, experiments on the production of ammonium paratungstate by the base-leaching process from rough tungsten ores produced by local individual miners in Jiangxi were carried out.The experimental results show the chemical components and properties of run-of-mine ore, the reaction temperature and pressure and the caustic soda concentration all have remarkable effects on the leaching rate. Technologically,by applying dispensation techniques and adding scheelite-decomposing agents the problem due to the high content of silicon and calcium in the ore can be solved . And a new process of tungsten production by the base-leaching method which had not been reported before was developed . By this process chemical reaction will go on without let-up during the operation while by the old one there are times when chemical reaction comes to be in equilibriumum and stops , and so the recovery rate can be noticeably increased , in fact,it reaches 99%.

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