Ammonium Paratungstate Preparing Tungsten Rod 2/2

Remarks:
1) The process conditions supposed to be: The temperature in the blue tungsten One-Reduction process may be: 530, 550, 580, 620, 650, 670℃, and the flow rate of hydrogen is 2.0~3.0m³/h, also the dew point is less than or equal to 60℃, boat loading amount is 300~350g, and the tungsten dioxide output will contain oxygen at rare of 12~14%;
2) The conditions of Secondary-Reduction are like bellows: temperature of 700, 750, 800, 830, 860, 860℃, the flow rate of hydrogen is 3.0~5.0 m³/h, the dew point is less than or equal to 60℃, boat loading amount is 280~320g.
5. Pickling
Washing the fine, medium and coarse tungsten powder respectively with the 5~6% concentration of hydrochloric acid and hydrofluoric acid to remove impurity;
6. Mix powders
Mix fine, medium and coarse tungsten carbide powder at the ratio of 20~25:50~60:20~25 in a mixer for 25 ~ 30min;
7. Forming at the condition of cold isostatic pressing
8. Sintering at high temperature
Sintering the tungsten billets which is pre-sintered in a vertical melting machine under the protection of hydrogen, set a certain conditions, then we get the tungsten which is needed.

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