Mainly divided into high temperature melt extraction and gas injection carbonization two stages.
A tungsten concentrate was extracted Melt (mixture of wolframite concentrates or Scheelite and wolframite concentrate) and the Na 2 Si0 3, NaCl mixed, at 1050 ~ 1100 ℃ melted and the following reaction occurs:
2(Fe, Mn)W0 4 +3Na 2 Si0 3 +16NaC1====(Na 2 W0 4 ·8NaCl)+Na 2 (Fe,Mn) 2 Si 3 0 9
The obtained Na 2 W0 4 ·8NaC1 phase is immiscible with the silicate phase, so it is layered by density, the lower layer is a chloride-tungstate phase, and the upper layer is a silicate phase. After two phases are separated by decantation, typically 98% to 99% WO 3 and a small amount of iron impurities into the manganese tungstate, typical conditions are:
Ingredients: black tungsten concentrate NaCl: Na 2 Si0 3 = 33:47:20, when using white tungsten as raw material, generally should add A1 2 0 3 and NaF as flux, but white tungsten and black tungsten according to 1:3 ~3:1 ratio addition can also avoid adding flux.
Temperature and holding time: 1050~1100 °C, 2h.
Chloride-tungstate phase composition: 25% to 30% WO 3 , about 0.24% FeO, about 0.3% MnO.
Silicate phase composition: about 0.5% WO 3 , about 36% (FeO + MnO).
B Gas injection carbonization The chloride-tungstate phase is supplemented with NaCl to adjust the ratio. At 1050~1090 °C, natural gas is introduced into the following reaction:
Na 2 W0 4 +4CH 4 ==== Na 2 0+WC+3C0+8H 2
WC, WC was washed with 10% HCl and 3% NaOH.
Typical conditions are: chloride-tungstate phase composition: containing 25% to 30% W0 3 (ie, Na 2 W0 4 is 31.7% to 38%).
Reaction temperature: 1050~1070 °C.
Carbon utilization rate in CH 4 : about 2.2% (semi-industrial scale data, the same below).
The recovery rate of W0 3 into WC; about 90%.
The total cost of WC powder: about 30% less than the traditional method.
After the above-mentioned carbonized product is ground, it is leached three times with 6 mol/L hydrochloric acid at 65 ° C to remove impurities, and the composition of the obtained product is roughly: total carbon of 5.99% to 6.14%; free carbon of 0.06% to 0.08%; S: 0.003%~0.014%; 0: 0.53%~0.55%, A1: 0.001%~0.005%; Ca: 0.005%~0.01%; Cr: 0.05%~0.3%; Cu: 0.007%~0.01%; Fe: 0.001%~0.05%; Mg: 0.001%~0.01%; Mo: 0.01%~0.1%; Si: 0.001%~0.01%; Ni: 0.03%~0.1%, the particle size is 1~20μm, accounting for 85%~90% .
A tungsten concentrate was extracted Melt (mixture of wolframite concentrates or Scheelite and wolframite concentrate) and the Na 2 Si0 3, NaCl mixed, at 1050 ~ 1100 ℃ melted and the following reaction occurs:
2(Fe, Mn)W0 4 +3Na 2 Si0 3 +16NaC1====(Na 2 W0 4 ·8NaCl)+Na 2 (Fe,Mn) 2 Si 3 0 9
The obtained Na 2 W0 4 ·8NaC1 phase is immiscible with the silicate phase, so it is layered by density, the lower layer is a chloride-tungstate phase, and the upper layer is a silicate phase. After two phases are separated by decantation, typically 98% to 99% WO 3 and a small amount of iron impurities into the manganese tungstate, typical conditions are:
Ingredients: black tungsten concentrate NaCl: Na 2 Si0 3 = 33:47:20, when using white tungsten as raw material, generally should add A1 2 0 3 and NaF as flux, but white tungsten and black tungsten according to 1:3 ~3:1 ratio addition can also avoid adding flux.
Temperature and holding time: 1050~1100 °C, 2h.
Chloride-tungstate phase composition: 25% to 30% WO 3 , about 0.24% FeO, about 0.3% MnO.
Silicate phase composition: about 0.5% WO 3 , about 36% (FeO + MnO).
B Gas injection carbonization The chloride-tungstate phase is supplemented with NaCl to adjust the ratio. At 1050~1090 °C, natural gas is introduced into the following reaction:
Na 2 W0 4 +4CH 4 ==== Na 2 0+WC+3C0+8H 2
WC, WC was washed with 10% HCl and 3% NaOH.
Typical conditions are: chloride-tungstate phase composition: containing 25% to 30% W0 3 (ie, Na 2 W0 4 is 31.7% to 38%).
Reaction temperature: 1050~1070 °C.
Carbon utilization rate in CH 4 : about 2.2% (semi-industrial scale data, the same below).
The recovery rate of W0 3 into WC; about 90%.
The total cost of WC powder: about 30% less than the traditional method.
After the above-mentioned carbonized product is ground, it is leached three times with 6 mol/L hydrochloric acid at 65 ° C to remove impurities, and the composition of the obtained product is roughly: total carbon of 5.99% to 6.14%; free carbon of 0.06% to 0.08%; S: 0.003%~0.014%; 0: 0.53%~0.55%, A1: 0.001%~0.005%; Ca: 0.005%~0.01%; Cr: 0.05%~0.3%; Cu: 0.007%~0.01%; Fe: 0.001%~0.05%; Mg: 0.001%~0.01%; Mo: 0.01%~0.1%; Si: 0.001%~0.01%; Ni: 0.03%~0.1%, the particle size is 1~20μm, accounting for 85%~90% .
Iguang digital flexographic printing plate series have the following advantages such ad good ablation sensitivity, excellent imaging performance, sharp reduction of independent dots and lines, smooth platemaking process, easy operating of back exposure, high exposure latitude, fast washing and drying, excellent printing accuracy, long run length. They are suitable for the printing of fine packaging, pre printing, labels, cosmetics, hygiene products and pharmaceutical packaging such as films, papers, folding cartons, paper cups, bowls and other printing.
Thermal Ctp Plate,Offset Printing Graphic Films,Aluminum Thermal Ctp Plate,Tp-K Printing Plates
SUZHOU HUAGUANGBAOLI PRINTING PLATE CO.,LTD , https://www.huabaoiguang.com