The possibility of using the chemical precipitation method of up-cycled ammonium paratungstate (APT) was studied and compared with the thermal decomposition method. WO 3 particles were synthesized by chemical precipitation method using a 1: 2 weight ratio of APT: Di-water. For thermal decomposition, APT powder was heated for 4h at 600 o C in air atmosphere. The reaction products were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), particle size analyzer (PSA), and field emission-scanning electron microscopy (FE-SEM). Thermogravimetric analysis (TGA) of the upcycled APT allowed for the identification of the sequence of decomposition and reduction reactions that occurred during the heat treatment. TGA data indicated a total weight loss of 10.78 % with the reactions completed in 658 o C. The XRD results showed that APT completely decomposed to WO 3 by thermal decomposition and chemical precipitation. The particle size of the synthesized WO 3 powders by thermal decomposition with 2 h of planetary milling was around 2 µm. During the chemical precipitation process, the particle size of the synthesized WO 3 powders showed a round-shape with ~0.6 µm size.

The possibility of chemical precipitation for recycled ammonium paratungstate (APT) was studied. WO 3 particles were synthesized by chemical precipitation method using a 1:2 weight ratio of APT:DI-water. At the 500℃ sintering temperature, the X-ray diffraction results showed that APT completely decomposed to WO 3 . For the granulated powder WC-Co, vacuum heat treatment at proper temperatures increases tap density and flow-ability. Hardness of the WC-Co thermal spray coating layer was measured in the range HV 831~1266. Spray conditions for the best characteristic values were an oxygen flow rate=1500 scfh, a fuel flow rate = 5.25gph and a gun distance = 320mm.