Tungsten Oxide

In production, for some reason, some Ammonium Paratungstate (APT) products are not qualified in terms of academic composition or physical properties. A small amount of ammonium paratungstate waste may be produced during the production process, which can be recycled. The method of recovering unqualified ammonium paratungstate is mainly by dissolving and filtering, and then recrystallization is carried out. Therefore the factory directly use ammonia as the solvent at high temperature to dissolve APT, but APT in ammonia water is solubility, lead to dilute solution concentration,the dissolution time is long. Thus, the modern industry began to gradually over the use of APT thermal decomposition into ammonium metatungstate for recycle. The working mechanism of thermal decomposition is to control the appropriate temperature, calcined APT can be converted to ammonium metatungstate (AMT). According to the high temperature decomposition performance of APT·H 2 O, when APT·4H 2 O

Yellow Tungsten Oxide  (YTO) is a kind of tungsten trioxide, because the early purification of WO 3  color is mostly yellow, so the early tungsten trioxide compounds are known as yellow tungsten oxide.  Yellow tungsten oxide two different sizes of different particles, showing different color. When the yellow tungsten oxide crystal size is about 1.5um, it appears to be yellow. When the yellow tungsten crystal size is about 15um, it appears to be green. Although the appearance of different, the characteristics are similar. Before 1970s, yellow tungsten oxide was widely used, and a large amount of tungsten oxide was used in the production of metal tungsten powder and tungsten carbide powder, and a large number of applications and production of tungsten alloy products, such as tungsten copper, tungsten nickel, tungsten nickel iron, tungsten silver, tungsten rhenium, thorium tungsten and so on. Another part is used in the manufacture of paints, coatings and catalysts for the pe

Ammonium Metatungstate (AMT) is an important compound product in the process of tungsten smelting. It can be prepared by thermal degradation of Ammonium Paratungstate (APT) and can also be prepared by ion exchange with ammonium tungstate solution. Ammonium tungstate water soluble white crystalline powder or slightly yellow, ammonium metatungstate dissolved in water, ammonium paratungstate slightly soluble in water, which is the difference between ammonium metatungstate and ammonium paratungstate. Ammonium metatungstate is widely used as a raw material for the preparation of capacitors, nuclear shielding, flame retardants and corrosion inhibitors. It is also an excellent raw material for preparing superfine tungsten powder, high gravity alloy tungsten powder, phosphotungstic acid, arsenotungstic acid, silicotungstic acid. In fact, what really makes ammonium metatungstate play an important role is in the field of petroleum processing. The field of petroleum processi

Ion Exchange method is the process of preparing ammonium metatungstate . It is made from ammonium wolframate solution or ammonium paratungstate.  This method is also one of the main methods for preparing ammonium metatungstate (AMT) at present. The main mechanism of ion exchange method is that use NH 4+  in H+ solution of strong acid or weak acid type H+ cation resin to process ion exchange. Under the condition of pH 3.5, H+ enters solution , cook for 5 hours at 98 °C. Converting ammonium tungstate into stable ammonium metatungstate solution. Then after evaporation and concentration, ammonium tungstate was converted to stable ammonium metatungstate solution. Again after evaporation and concentration, AMT crystals were prepared by freeze crystallization or spray drying. The resin saturated by NH 4+  is recycled after treatment with hydrochloric acid solution.  Because of the simple process and convenient control, the ion exchange method can avoid the formation of AP

Ammonium Metatungstate (AMT) is an important compound product in tungsten smelting process.It is widely used in areas.  The common methods of preparing ammonium metatungstate include thermal degradation and ion exchange, extraction, nanofiltration, electrodialysis and neutralization. Nanofiltration membrane is a new type of pressure driven separation membrane developed since 1980s. Nanofiltration method is a membrane separation technique, which is independent from reverse osmosis membrane technology. Filter membrane is the main focus of nanofiltration. The separation performance of nanofiltration membrane is between reverse osmosis and ultrafiltration membrane. It has a good removal effect on low molecular weight substances, high valence ions, low valence cations and anions. Therefore, some scholars used the nanofiltration method to prepare ammonium metatungstate (AMT) from the original solution of ammonium paratungstate (APT) crystallization. The separation of ch

The extraction method is a preparation process that use ammonium tungstate with ammonium tungstate solution as raw material.  This method is also one of the processes for preparing Ammonium Metatungstate (AMT) at presnt. The extraction principle of ammonium metatungstate (AMT) extraction method is similar to that of ammonium tungstate extraction method, which needs to experience four stages including extraction, water washing and stripping. The whole extraction process is carried out in a box-type mixer-settlers, the difference is that in the reverse extraction operation, the concentration and dosage of the extractant are different. In the process of production, using ammonium tungstate solution as raw material, ammonium metatungstate was extracted by solvent extraction, extraction of NH4+ ion from ammonium metatungstate solution by a cationic extractant, then, the solution of pH in the condition of 3~4, ammonium metatungstate solution was obtained by reverse extraction.