Method for Producing Ammonium Metatungstate From Ammonium Paratungstate A method is disclosed for producing ammonium metatungstate from ammonium paratungstate. The method involves first roasting the ammonium paratungstate at from about 275 to about 300 for from about 10 hours to about 20 hours.

Process for Preparing Ammonium Metatungstate A process for preparing ammonium metatungstate using ammonium paratungstate as raw material comprising: (A) leaching wet ammonium paratungstate with nitric acid to obtain a dilute solution ofammonium metatungstate.

Method for Making Ammonium Metatungstate Prepare an ammonium paratungstate mixture including solid ammonium paratungstate and water. The mixture is contacted with a cation exchange material.

Kinetic Study of Retro-Aldol Condensation of Glucose to Glycolaldehyde Withammonium Metatungstate as Catalyst The kinetics of the retro-aldol condensation of glucose to glycolaldehyde was studied in a batch reactor at 423-453 K using ammonium metatungstate.

A NEW PRODUCTION METHOD OF AMMONIUM METATUNGSTATE—DONNAN DIALYSIS METHOD Zhou Kanggen (Department of Metallurgical Science and Engineering, Central South University of Technology, Changhsha 410083, China) Chen Xiaowen (Changsha Research Institute of Environmental Science, Changhsha 410083, China)

Pyrolysis preparation of WO3 thin films using ammonium metatungstate DMF_water solution for efficient compact layers in planar perovskite solar cells The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate(（NH4）6H2W12O40)DMF/water solution, and successfully applied as the efficient compact layers for the planar perovskite solar cells. The influence of the WO3 film thickness and the rinsing treatment of CH3NH3 PbI3 thin film with isopropanol on the photovoltaic performance of the corresponding perovskite solar cells was systematically investigated. The results revealed that the perovskite solar cell with a 62 nm thick WO3 compact layer achieved a photoelectric conversion efficiency of 5.72%, with a short circuit photocurrent density of 17.39 m A/cm2, an open circuit voltage of 0.58 V and a fill factor of 0.57. The photoelectric conversion efficiency was improved from 5.72% to 7.04% by the isopropanol rinsing treatment.

Method of Producing Crystalline Ammonium Metatungstate This invention relates to an improved method for pro ducing ammonium metatungstate. More particularly, the invention is concerned with a method for preparing ammonium metatungstate in crystalline form employing ammonium paratungstate as the starting material.