2019年12月23日星期一

Cyclohexanone Catalytic Reaction by Sodium Tungstate and Hydrogen Peroxide Mixed

Cyclohexanone is an important chemical raw material, widely used in fibers, synthetic rubber, industrial coatings, pharmaceuticals, pesticides, organic solvents and other industries.

Cyclohexanone is the main intermediate for the synthesis of caprolactam and adipic acid, and it is also a raw material for the preparation of spices, rubber antioxidants, adhesives, vinegar and fruit preservative phenolic phenol, and can also be used as fine chemical auxiliaries.

cyclohexanone production plant image

The traditional way to produce cyclohexanone is to produce cyclohexanol by hydrogenation of cyclohexanol, and then to reduce the cyclohexanol to the ring chamber by chemical method. There are two conventional preparation methods: One is in zinc catalyzed by 400 to 500 °C under oxidative dehydrogenation to cyclohexanone; The other was prepared by adding chromic acid catalyst with bleaching powder as oxidizing agent under weak acid condition. Among them, there is a problem, that is, there is no ideal catalyst, or the reaction conditions are harsh; or chromic acid is a toxic carcinogen, polluting the environment.

With the further study of sodium tungstate, the scholars found that the synthesis of adipic acid with cyclohexanone can be successfully catalyzed by sodium tungstate and hydrogen peroxide, scholars try again, using sodium tungstate as the main compound of hydrogen peroxide (H2O2), adding oxalic acid or phosphomolybdic acid and other acidic oxidant, made of tungstate compound catalytic agent. Through the catalysis of sodium tungstate composite catalyst, the synthesis process of the ring tunnel is quite smooth, the conclusion is that when the reaction temperature is 80 °C and the reaction time is 6h, only a small amount of tungstic acid compound catalyst mixture is used, the cyclohexanone yield is 98.2%, and the efficiency is 20% higher than the traditional chromic acid oxidizer.

Practice has proved again that sodium tungstate and hydrogen peroxide mixture can not only catalyze the synthesis of adipic acid from cyclohexanone, it also catalyzes the synthesis of cyclohexanol by cyclohexanone and may be a good catalyst for this type of chemical material, the most important thing is that sodium tungstate combined with hydrogen peroxide is not only effective, but also environmentally friendly, and can provide a better production environment for enterprises and society.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Tin Removal From Waste Tungsten Alloy Recycle

With the shortage of tungsten ore resources, the utilization of tungsten resources becomes more and more urgent.

Waste tungsten alloy is one of the main sources of tungsten recovery, according to statistics, about 35% of the tungsten in Europe and America developed from waste tungsten alloy recycling. With the emphasis on tungsten resources in China, the recycle rate of tungsten resources in China has been increasing year by year, and it has reached 20%.

In the tungsten recycling process, the sodium carbonate melting method of waste tungsten recycle process technology is more mature and wide applicability of the program, but it is inevitable that the leaching process in recycling of waste tungsten, scrap tin, phosphorus, chromium, molybdenum and other impurities may also enter coarse sodium tungstate solution, thus affecting the purity of tungsten products. The main impurities of the waste alloy are different, the treatment method varies according to material, here to introduce tin removal from crude sodium tungstate solution method of tin rich impurities.

 impurities removal in sodium tungstate solution image

In the alkaline process, the purification of sodium tungstate from waste alloy is usually made by magnesium ammonium phosphate method or phosphorus arsenic magnesium salt method. In the impure sodium tungstate solution, a small amount of soluble magnesium salt is added to produce ammonium phosphate, and generated magnesium salt or phosphorus arsenic magnesium salt, so as to remove arsenic and phosphorus.

In the impure sodium tungstate solution, a small amount of soluble magnesium salt is added to produce ammonium phosphate, magnesium salt or phosphorus arsenic magnesium salt, so as to remove arsenic and phosphorus. In the process of pH, silicon can simultaneously remove from the solution, but it can not effectively remove tin and tin, the best filtering stage only in the crude sodium tungstate solution phase, the follow-up process is very difficult to deal with.

For the treatment of tin in crude sodium tungstate solution from waste tungsten alloy recycle, some foreign scholars have proposed the scheme, which can be roughly divided into four stages. (1) Adding ammonium or hydrogen hydroxide to sodium tungstate solution. (2) Adding sulfuric acid, transfer PH to 9.5-10 and stir for half an hour. (3) Adding magnesium chloride into the solution which has been ammoniation and adjusted the pH value, and then the mixture is stirred for a period of about 12 hours to form a slightly soluble tin, arsenic, phosphorus and silicon compounds. (4) Stand aside for about 3 hours. A substance containing tin compounds can be precipitated.

When the insoluble substance is removed, the filter can be used to filter the insoluble matter in the solution and to obtain the purified solution containing tungsten, the content of tin obtained by the purified solution can reach or better than the purity of APT - 0, and it is very economical and feasible to evaluate the content of the waste alloy by the recycling standard of APT.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Sodium Tungstate Preparation From Scheelite Slime Recycle

Sodium tungstate is an important chemical raw material and an important intermediate product in tungsten metallurgy production.

Generally speaking, industrial production of sodium tungstate mainly uses scheelite concentrate or wolframite concentrate as raw material, and the production cost is higher.

In the tungsten concentrate production process, there are often some tungsten due to process or equipment reasons, lead to part of the tungsten ore grinding machine into powder or no successful flotation into the tailings, forming tungsten fine mud.

scheelite slime recycle image

The conventional recycle process of tungsten slime is tungsten slime - sodium tungstate - ammonium paratungstate. How can the sodium tungstate be recycled more efficiently by using tungsten slime? Compared with wolframite, fine scheelite slime is characterized by lower grade, more impurities, and more calcium containing molybdenum, which is more difficult to purify. In view of the above, we can use hot ball milling alkali decomposition ion exchange APT evaporation crystallization process. It has a strong adaptability to high calcium and low grade ore. It has three main stages:

1. The tungsten fine slime is decomposed by alkali method and hot ball milling, and most impurities are inhibited in the slag, so that the WO3 is transferred into the solution to produce sodium tungstate solution, and most of the impurities (P, As, Si, etc.) are left in the slag. 

2. The obtained sodium tungstate solution is evaporated and crystallized at once, and to recycle the alkali and remove impurities such as P, As, Si etc..

3. Sodium tungstate crystals were dissolved and filtered to obtain sodium tungstate solution. Unlike the sodium tungstate solution obtained from the scheelite concentrate, there is more molybdenum in sodium tungstate solution. The main work of this stage is to remove the molybdenum, can be selected by ion exchange or selective precipitation of tungsten and molybdenum separation. The sodium tungstate solution after molybdenum can be obtained by two times evaporation and crystallization, and can be converted into ammonium tungstate solution by ion exchange method, and then APT is prepared.

4. The above process can effectively deal with low grade and scheelite fine slime containing calcium and molybdenum. Some data show that the process of recycling scheelite fine slime from ore in Hunan, China, has a total recovery rate of 60-70%, and the effect is very good. Moreover, from the cost point of view, the majority of tungsten slime, according to WO3 measurement, the cost is only 60%-70% of the concentrate price. The recycle of tungsten slime is an effective way to reduce the cost of mining and prolong the mining life of the mine.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


2019年12月11日星期三

Chromium Removal From Waste Tungsten Alloy Recycle

With the shortage of tungsten ore resources, the utilization of tungsten resources becomes more and more urgent. Waste tungsten alloy is one of the main sources of tungsten recycle.

According to statistics, about 35% of the tungsten in Europe and America developed from waste tungsten alloy recycling. With the emphasis on tungsten resources in China, the recycle rate of tungsten resources in China has been increasing year by year, and it has reached 20%.

In the waste recycling process of tungsten alloy technology, recycle process of waste tungsten by sodium carbonate smelting process is relatively mature and widely applicable, much as it is used, but a lot of problems also appeared in the actual production, the most troublesome is chromium. During the leaching of waste tungsten alloy by sodium carbonate smelting process, a large amount of chromium impurity elements also enter into sodium tungstate solution, which can not meet the purity of tungsten products.

waste tungsten alloy image

The chemical properties of chromium show that the precipitation of chromium from sodium tungstate solution requires the reduction of Cr6+ to Cr3+, this process can be done by acid and alkali, but in the current industrial atmosphere, the alkaline process has the mass base.

If you want to remove chromium, you have to do it once more, removing impurities is necessary. In general, sodium tungstate crystals need a series of procedures, such as dissolution neutralization purification, removal of sulfide, acid extraction, extraction stripping, APT crystallization, etc.. Some experts believe that the removal of chromium during the curing stage is a wise choice, this is mainly the curing process can be carried out with the removal of chromium and molybdenum removal, this is less than the two stages of reduction, hydrolysis and filtration in the dissolution stage of crude sodium tungstate;

In the process of removing chromium by vulcanizing stage, sodium sulfide 4 times of theoretical quantity is added into the present process of molybdenum removal by sulfuration, besides, the chromium removal was controlled when the reaction pH value was 8-9, by selecting suitable temperature and aging time, better chromium removal effect can be achieved, moreover, it is necessary to add a filtration process on the basis of the original production process to accomplish the task. More importantly, in the curing stage, the APT obtained from chromium treatment can basically achieve the purity of APT - 0. From the recycling standard of waste alloys, this should be a very good result.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Sodium Tungstate Is Expected To Be a New Drug For Reducing Blood Lipids

Sodium tungstate is a kind of tungstate, and its chemical formula is Na2WO4.

In nature, sodium tungstate appears to be colorless crystalline or white crystalline powder, and sodium tungstate is now known to replace sodium vanadate in the treatment of diabetes. However, with the study of sodium tungstate in the field of medical treatment, some American scholars have suggested that sodium tungstate can also be used to treat hyperlipidemia and obesity.

Hyperlipidemia refers to the high level of blood lipids, can directly cause some serious harm to human health diseases, such as atherosclerosis, coronary heart disease, pancreatitis and obesity, this symptom is more common in the United States, which is related to diet. In medicine, high blood lipids are caused by elevated levels of triglycerides (TG) and total sterols (CHO) in the blood.

drugs image

In order to investigate the possibility of sodium tungstate in the treatment of hyperlipidemia, Chinese medical workers were tested with mice. During the course of the experiment, using poloxamer 407 intraperitoneal injection of rodents caused by elevated blood lipids, obtained hyperlipidemia animal model. Then the mice were divided into 4 groups, which were treated with ionized water, 100mg/Kg sodium tungstate, 200mg/Kg sodium tungstate and bezafibrate tablets (for the treatment of hyperlipidemia). By contrast, the researchers found that sodium tungstate had a hypolipidemic effect on hyperlipidemic Kunming mice, which significantly decreased the levels of serum total cholesterol (CHO) and triglyceride (TG) levels, lipid cholesterol (HDL-CHO) was elevated at the same time as the ester, and the effect of sodium tungstate was better than bezafibrate at 200 mg / kg.

The results showed that sodium tungstate had a hypolipidemic effect on hyperlipidemia, which could significantly reduce the level of serum total cholesterol and triglyceride, and balance the level of high density lipoprotein (HDL). Although sodium tungstate is currently in experimental phase, there is no doubt that sodium tungstate has the potential to develop new lipid-lowering drugs. As we all know, the formation of high blood fat is related to obesity, and the decrease of blood lipid often indicates the success of weight loss, in addition, hyperlipidemia is often associated with diabetes and hypertension. In the future, sodium tungstate can become a new blood lipid lowering drug which can control diabetes and control hyperlipidemia, it may reduce the pain of many patients.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Sodium Tungstate Can Also Treat Diabetes

Sodium tungstate is a kind of tungstate, and its chemical formula is Na2WO4.

In nature, sodium tungstate is a colorless crystalline or white crystalline powder, and is often used as a plant protection, metal corrosion inhibitor and photocatalytic agent because of its non-toxic and environmental advantages. But is rarely known by people that sodium tungstate can also be used to treat diabetes.

Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia. Hyperglycemia is caused by insulin secretion defects or impaired biological effects, or both. The consequences of diabetes are easy to cause eye, kidney, heart, blood vessels, nerves of chronic damage, dysfunction, such as high blood pressure, stroke, etc., is a healthy killer of middle-aged and elderly people. The traditional compound for the preparation of diabetes is vanadate, which is a simple inorganic vanadium compounds such as sodium vanadate, vanadyl sulfate etc.. Vanadium insulin has been widely used for many years to alleviate the incidence of diabetes and improve the physical condition of the diabetic and mimic the physiological function of insulin, however, vanadium has low toxicity, and long-term use of drugs will inevitably harm the liver, kidney and other organs.

sodium tungstate in the treatment of diabetes image

Many studies have found that sodium tungstate, like vanadate and other trace elements, can promote the synthesis and accumulation of glycogen, promote glycolysis and inhibit gluconeogenesis.

There were medical workers using sodium tungstate and sodium vanadate to compare tests, in animal studies, sodium tungstate can reduce normal blood glucose levels in type 1 and type 2 diabetic rats without causing hypoglycemia, even after a considerable period of withdrawal, the blood glucose levels of the treatment group remained normal or lower than the sodium vanadate control group. Although sodium vanadate has good hypoglycemic effect, but after a period of withdrawal, blood glucose levels rose earlier in animals treated with sodium vanadate. More importantly, although sodium salts are similar in biological properties to vanadate and other trace elements, sodium tungstate is less toxic and highly bioavailable.

Based on the above factors, it can be predicted that tungstic acid has more broad prospects for the prevention and treatment of diabetes than other trace elements, in the near future, with the end of clinical trials, sodium tungstate will bring the gospel to more diabetic patients.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


What You Don't Know About The Applications of Sodium Tungstate

Sodium tungstate is a kind of tungstate, and its chemical formula is Na2WO4.

The appearance is colorless crystalline or white crystalline powder, soluble in water, insoluble in ethanol, slightly soluble in liquid ammonia, when confront a strong acid it is broken down into tungstic acid dissolved in water.

Sodium tungstate, as a raw material for chemical synthesis of tungsten, is an important intermediate in the transformation of tungsten into metals, usually, the intermediate product is broken down by alkaline process, and sodium tungstate is obtained, but in here sodium tungstate refers to crude sodium tungstate containing impurities. It also needs to be obtained by ion exchange, precipitation, extraction and other processes. Finally, APT is obtained by evaporation crystallization. Although sodium tungstate is an intermediate product of tungsten in the process of transformation, we use a lot of sodium tungstate, usually used in industrial products in tungstate refers to chemically pure sodium tungstate, sodium hydroxide is prepared by tungsten trioxide.

sodium tungstate image

Sodium tungstate is not only a chemical product, but also a high-quality semiconductor material. It can be used to control environmental pollution and manufacture new energy materials. The known applications are as follows:

1. Applied in the manufacture of metal tungsten, tungstic acid, tungstate, etc..

2. Applied in mordant, analytical reagent, catalyst, water treatment chemicals, manufacturing fireproof, waterproof materials, as well as dodecatungstophosphate, borotungstate etc..

3. The compound of sodium tungstate and polyaspartic acid can be used as a metal corrosion inhibitor to prolong the service life of metals in corrosive environments such as sea water.

4. Textile agents used as a weighting agent for fabrics. This product is used as a fabric aid and consists of a mixture of sodium tungstate, ammonium sulfate, ammonium phosphate, etc., used for fireproofing and waterproofing of fibers. This kind of fiber can be made of fireproof rayon and rayon, can also be used for leather tanning.

5. The combination of sodium tungstate and hydrogen peroxide can effectively degrade dye wastewater methylene blue.

6. Sodium tungstate can optimize plant nitrogen absorption, improve fruit quality and avoid nitrogen loss.

7. Sodium tungstate can be used to adjust the absorption of NO3- N by Cassia albus, which increases the production of diesel fuel.

8. Sodium tungstate can be made into antifreeze by compounding, so as to prevent the tea plant from "cold disaster".

In addition, some scholars believe that sodium tungstate can promote islet cell proliferation, differentiation and secretion, reduce serum total cholesterol (CHO) and triglyceride (TG) level, and can be used as raw materials for the treatment of diabetes, can also be used for reducing blood lipid and weight loss.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.




2019年10月23日星期三

Monoalkyl Phosphate Preparation by Cesium Phosphotungstate

Monoalkyl phosphate is an important surfactant, widely used in chemical fiber, textile, leather, plastics, paper making and cosmetics. 

Monoalkyl phosphate usually synthesized by the esterification of phosphoric acid with aliphatic alcohols by esterification. The commonly used phosphorus agents are three oxychloride (POCl3) and phosphoric acid.

When phosphorus oxychloride is used as an agent for HCL, it is easy to cause environmental pollution, when phosphoric acid is used as a phosphate agent, although it is environmentally friendly, it is difficult to synthesize monoester, diester and three ester because of the low activity of phosphoric acid. Is there a way to improve the activity of phosphoric acid to help balance the benefits of the environment?

monoalkyl phosphate preparation image

Cesium phosphotungstate is a kind of heteropoly acid. It is a new type of multifunctional catalyst. It has not only oxidation reduction property, but also high catalytic activity and good stability, it can be used for homogeneous and heterogeneous reactions, and even can be used as phase transfer catalyst, the most important thing is that it is pollution-free to the environment. Some scholars have studied the synthesis of mono twelve alkyl phosphate by the direct esterification of lauryl alcohol and 85% phosphoric acid with cesium phosphotungstate as catalyst. Through investigation, we found that cesium phosphotungstate in the reaction process showed very high activity during the catalytic reaction, under the catalytic action of cesium phosphotungstate, the selectivity of MAP is 90% with the attraction between lauryl alcohol and phosphoric acid, a single twelve alkyl phosphate has been successfully synthesized. The effect is not weaker than three phosphorus oxychloride (POCl3). The most important is that it is safer and more environmentally friendly with phosphoric acid.

Over the years, cesium phosphotungstate has been recognized more and more by virtue of its excellent catalytic performance and non-toxic and harmless strength. So, when you're not satisfied with the catalytic effect of a certain chemical, you might be able to try cesium phosphotungstate.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


The PK Between Tungsten Trioxide and Titanium Dioxide Photocatalytic Performance

Photocatalysis is a photochemical reaction in the presence of a catalyst, it is a new science and technology.

Common photocatalysts include metal oxides (TiO2, ZnO, Fe2O3, Bi2O3, WO3) and metal sulfides (CdS, MoS2, MoSe2). Titanium dioxide TiO2 is the most white thing in the world, 1 grams of titanium dioxide can paint more than 450 square centimeter area to white. So it's the best paint for making white oil paint. The most well-known is that semiconductor photocatalysis performance of TiO2. TiO2 photocatalysis is widely used because of its high activity, photochemical stability, non-toxic and cheap.

Tungsten trioxide TiO2 is a kind of tungsten compounds that are widely used, It can be used not only for hard alloys, but also for dyes, the most commendable thing is that tungsten trioxide also with excellent photocatalytic performance. Like TiO2, WO3 also has high activity, photochemical stability, non-toxic and so on. If you compare the two, who can be better?

tungsten trioxide and titanium dioxide image

According to the data, TiO2 was the first compound to enter the field of photocatalysis, in 1972, the Japanese discovered that light irradiated TiO2 particles could cause water to undergo a sustained redox reaction, and began the history of photocatalysts. For a long time, TiO2 has been the preferred material for photocatalysis. Until 1983, the scholars in China used WO3 to treat printing and dyeing wastewater for the first time, and achieved very good results. Since then, WO3 has been discovered in application field and application, and gradually catch up from behind, outshining TiO2. How can WO3 compete with TiO2?

TiO2 was used as photocatalyst for a long time. But there are two fatal problems with the performance of TiO2, first, TiO2 has a narrow range of absorption of sunlight, which limits its use of solar energy. Second, photocatalytic reaction efficiency is low, generally not greater than 1%. With the increasingly serious problem of environmental water pollution, TiO2's capacity is too poor, TiO2's weaknesses are the strengths of WO3. From the performance point of view, the activity of WO3 photocatalytic degradation on organic pollutants is higher, the absorption and utilization on sunlight is better.

Tungsten trioxide has better chemical compatibility, WO3 can be mixed with ZnO, Bi2O3, rare earth La, Eu, Y and other elements to form a tungstate photocatalyst, not only pollution control, but also classify the printing and dyeing wastewater, antibiotic wastewater, metal wastewater targeted governance. Therefore, ignoring the price factor, the performance of WO3 undoubtedly has stronger competitiveness.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Cesium Tungsten Bronze

Cesium tungsten bronze (CsxWO3) is synthesized by solid phase method or liquid phase method with cesium carbonate and sodium tungstate as raw materials.

Cesium tungsten bronze is also called cesium tungstate. CsxWO3 is a non stoichiometric functional compound with a special structure of oxygen eight surface, with low resistivity and low temperature superconducting properties. But in recent years, cesium tungsten bronze is popular for its excellent UV and near infrared shielding performance, with high efficiency, insulation and light reflection effect, this makes it good in the manufacture of special glass, high-end insulation film and LCD screen manufacturing.

In recent years, with the increasing popularity of cesium tungsten bronze, more and more scholars have begun to discuss the liquid phase preparation of cesium tungsten bronze. Some scholars have adopted the hydrothermal method to obtain cesium tungsten bronze, sodium tungstate and cesium carbonate were used as raw materials, in the citric acid solution, the CsxWO3 powder with six square Cs0.33WO3 structure was synthesized by hydrothermal method, and the CsxWO3powder was fully ground and dispersed in a citric acid solution, cesium tungsten bronze film was prepared on glass slide by dipping and dipping method. 

future house image

Through the test of cesium tungsten bronze film, we can draw a conclusion, the CsxWO3 powders obtained by hydrothermal method exhibit strong ultraviolet absorption and short wave near infrared absorption performance, moreover, the absorbance in short wave near infrared region increases with the prolonging of reaction time and the increase of citric acid content. The hydrothermal method failed to solve the cost problem more effectively, but the most important advantage of hydrothermal method is low carbon environmental protection, and the process is easier to control than solid phase method. If more details are to be improved, the large-scale application of cesium tungsten bronze will soon be possible. 

In recent years, with the improvement of people's living requirements, the concept of green house has been popular among people, in the near future, nanotechnology will seep into every detail of live, perhaps our walls, windows, doors, and floors can be made of special glass or paint or film to achieve automatic thermostat adjustment. There is no need to open air-conditioning in summer or open heating installation in winter, real energy saving and environmental protection are achieved, and at that time, such as cesium tungsten bronze and other new materials will certainly have unlimited room for development.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.

【Know Tungsten】Sodium Tungstate Applications

Sodium tungstate, Na2WO4•2H2O, a tungstate of sodium, is useful as a source of tungsten. It is prepared from tungsten ores to manufacture tungsten by reducing it. It is often found as dihydrate.
sodium tungstate image
sodium tungstate image

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.

2019年9月19日星期四

Adipic Acid Catalyzed Preparation by Tungstic Acid

Adipic acid is mainly used for nylon 66 engineering plastics and raw materials, and in the production of various ester products.

Adipic acid is also used for polyurethane elastomer material, acidifier various foods and beverages, sometimes its better than citric acid and tartaric acid. Adipic acid has many functions and a huge demand, but it is a big polluter. The industrial process mainly uses nitric acid to oxidize cyclohexanol and cyclohexanone (KA oil). The method has high yield, but nitric acid seriously damages the equipment and produces a large amount of nitrogen oxides which pollute the environment seriously. With the improvement of human environmental protection consciousness, people urgently need to find environmental protection and pollution-free solutions to solve the problem of adipic acid production.

adipic acid producing equipment image

In recent years, Cao Fabin, a scholar, has proposed that adipic acid is used as catalyst to synthesize adipic acid, according to previous experience, he uses tungstic acid and hydrogen peroxide (H2O2) to make an acidic additive of tungstic acid, in the absence of organic solvent and phase transfer agent, catalyzed 30% hydrogen peroxide oxidation of cyclohexanol to synthetic adipic acid. In the research process, Cao Fabin also found that the addition of suitable active agents could help catalyze the catalytic effect of tungstic acid. After comparing the inorganic substances such as phosphoric acid, phosphorous acid, oxalic acid, resorcinol, sulfonic acid and salicylic acid, he thought that it was most suitable for adding sulfonic acid to an acidic additive of tungstic acid.

The final result shows that when the amount of tungstic acid is 2.5mmol, tungstic acid: acid additive: cyclohexanol: when hydrogen peroxide is 1:1:40:176 (molar ratio), in acid additive, the effect of cyclohexanol oxidation with sulfonic acid and salicylic acid is the best, the yield of reactive adipic acid was 87.8% and the purity was 99.9%. It is worth mentioning that, after the synthesis of adipic acid, acid sulfonic acid and salicylic acid can be put into production again and reused fifth times. The yield of adipic acid separation is still up to 81.5%.

China is a major producer of tungsten, it is feasible to produce an acidic additive of tungstic acid to realize the scale production of adipic acid, using tungstic acid catalyst cyclohexanol method not only has high efficiency, but also to achieve cost control, more importantly is environment friendly. Environmental protection is increasingly valued, enterprises can reduce investment in environmental protection because of the new process, and achieve benefits.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Why Sodium Silicate Is The Most Common Inhibitor of Scheelite Flotation

There are many inhibitors of scheelite flotation, but the most popular and widely used is sodium silicate, which is recognized by industry as the most effective and cost effective inhibitor.

Sodium silicate, commonly known as water glass, the molecular formula Na2SiO3 is a water-soluble silicate, is a kind of mineral binder, non-sulfide ore, especially a typical inhibitor of silicate minerals. Sodium silicate is selected in the floating scheelite and playing two main functions: one is to make the silica gel modified by physical adsorption on mineral surface, two is the adsorption of SiO32-, HSiO3-, OH- and H+ on the surface of quartz and silicate minerals, which increases the electronegativity and hydrophilicity of the mineral surface.

In scheelite flotation process, sodium silicate was inhibited in quartz, calcite and silicate, generally speaking, sodium silicate is selective when used in low dosage, but using too much will lose the selectivity.

water glass image

Therefore, in order to deal with the complex components of scheelite, people will find helper for sodium silicate, and achieve the ideal effect through the collocation of flotation. The main auxiliary of sodium silicate mainly has the following three members:

1. Metal ions such as AL3+, Mg2+, Cu2+, Fe2+, Ca2+, the combination of sodium silicate with these multivalent metal cations can be effective for fluorite and calcite, the main reason is that sodium silicate and metal cation form metal silicate colloid, and the selectivity of adsorption is enhanced.

2. Sodium silicate combined with Na2CO3. This combination can be used for the separation of scheelite from silicate minerals, its main function is CO32-, HCO3- can be preferentially adsorbed to the surface of calcium minerals, prevent the adsorption of sodium silicate, moreover, silicate minerals can be strongly inhibited by sodium silicate.

3. Temperature. The pulp heated 60-80 °C, can be used for separation of scheelite and calcite, the reason is that the sodium silicate can selectively remove the oleate anion on the calcite surface after heating.

Thus, in the process of scheelite flotation, how to use sodium silicate inhibitors is also a skill, whether it is heated flotation or room temperature flotation, according to the characteristics of sodium silicate can make scheelite flotation to achieve a multiplier effect.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Nano Cesium Tungsten Bronze Preparation by Solvothermal Method

Cesium tungsten bronze (CsxWO3) is synthesized by solid phase method or liquid phase method with cesium carbonate and sodium tungstate as raw materials.

Therefore, cesium tungsten bronze is also called cesium tungstate. Cesium tungsten bronze CsxWO3 has the function of oxygen compounds in eight face special structure, with low resistivity and low temperature superconducting propertiesaterials. It mainly used to make high-temperature insulation coating, building glass, Low-E glass, automobile insulation film, plant planting shed, LCD screen and so on.

Synthetic of cesium tungsten bronze can be obtained by solid phase method and liquid phase method. In the earlier period, most of cesium tungsten bronze was prepared by solid phase synthesis, such as vapor phase reduction and hydrogen reduction, but the synthesis of solid phase is difficult and the cost is too high. Therefore, with the increasing attention of cesium tungsten bronze, more and more scholars began to study the liquid phase preparation of cesium tungsten bronze and find a way to reduce the manufacturing cost.

cesium tungsten bronze image

Scholars dissolved 400kg sorbitol in a jacketed reactor and dissolved it into tungstate and cesium sulfate, the ratio of the mass ratio of tungstic acid to cesium sulfate is 1 : 0.33, the quality of sorbitol is 3 times the total mass of tungstic acid and cesium sulfate, after high speed stirring 30 min, pump into homogeneous machine to carry on the cycle homogenization, after 60 min, the product is pumped into the high temperature reactor which has been heated to 150 °C, and the high pressure reactor speed is set to 180 r/min. When the above material is completely transferred to the autoclave, turn off the valve of the high-pressure reactor, gradually increase the temperature of the reactor to 350 degrees, and keep 600 min for 150 degrees, release the reaction product, adding deionized water to the filter press, washing with deionized water and absolute ethanol until the sulfate content is below 100 mg/kg, and the content of ethanol is more than 80%, the filter cake is placed in a vacuum oven for drying, and then mechanical pulverization and air flow grinding are carried out to obtain the target product - dark blue cesium tungsten bronze nanometer powder.

The cesium tungsten bronze nano-slurry was added to the acrylic emulsion to coat the film, and the functional film with excellent transparent insulation performance was obtained. The results show that the nanometer tungsten bronze powder with good quality can be prepared by solvothermal method. The transmittance of the functional thermal barrier film at 950 nm is 9.2%, the transmittance of visible light at 550nm is 71%, fog is 0.5%, and the film has excellent infrared absorption characteristics, and it is an excellent transparent thermal insulation material.

Unfortunately, scholars do not seem to solve the cost problem of cesium tungsten bronze by using solvent method. Moreover, the organic solvents in solvent thermal process are volatile and the production process will cause environmental pollution. However, it is certain that the quality of cesium tungsten bronze prepared by solvothermal method is better than hydrothermal method. The results show that the nano cesium tungsten bronze film prepared by solvothermal method not only has good heat insulation effect, but also has a long service life, and the service life is more than 20 years.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Cesium Tungsten Bronze Preparation by Heat Insulation Film

Cesium tungsten bronze (CsxWO3) is a kind of tungstate powder synthesized by solid phase method or liquid phase method with cesium carbonate and sodium tungstate as raw materials.

Cesium tungsten bronze is also called cesium tungstate. As everyone knows, the sun's heat is mainly concentrated in the two part of the visible light and near infrared light, cesium tungsten bronze CsxWO3 particles can ensure good visible light transmittance, and can cover most of the near infrared caused by heat, and cesium tungsten bronze is an ideal material for manufacturing automotive insulation film.

However, in the manufacture of cesium tungsten bronze CsxWO3 heat insulation film, it is found that CsxWO3 particles are difficult to disperse in solution, and attached to the heat insulation film. In order to realize the near infrared shielding function of cesium tungsten bronze CsxWO3 particles, the dispersion and stability of particles in slurry must be improved, particle dispersion is enhanced by ball milling, ultrasonic addition, dispersant and surface modification.

nano cesium tungsten bronze film image

Some scholars use polyvinyl alcohol (PVA), polyvinyl butyral (PVB) and polyvinyl pyrrolidone (PVP) of the three kinds of membrane material to test cesium tungsten bronze heat insulation film preparation. After the Cs0.33WO3 slurry was obtained by hydrothermal method, the slurry was added into the 15L film solution after 3 hours ball milling and 20 minute ultrasonic wave addition,  at 80 °C, the water was mixed with 10min. Then, the foam 1% was added and the mixture was heated and stirred 20min, finally, three different materials of PVA, PVB, PVP cesium tungsten bronze coating film were prepared.

The results show that the average particle size of Cs0.33WO3 particles decreases after milling 3H with water as solvent. At the same time, the dispersion stability has been greatly improved. After adding polyethylene glycol - 400, the stability of cesium tungsten bronze particle dispersion is further improved, showing excellent near infrared shielding performance, through the transverse contrast of three kinds of film materials, scholars believe that PVA and PVP are Cs0.33WO3 coatings for film-forming substances has good transmittance of visible light and near infrared shielding property, at the same time, the cesium tungsten bronze coating with PVP as film forming material has the best adhesion strength.

If you have any inquiry of tungsten, please feel free to contact us:
Tel.: +86 592 5129696/+86 592 5129595
Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.


Green Catalytic Activity of Phosphotungstic Acid for Four Hydrogen Sulfide

Four hydrogen sulfide is a chemical intermediate of nitro spray paint, rubber and other solvents, so is often used in the protection of hydr...