2022年5月27日星期五

Tungsten Ores Directly Produces Coarse-Grain Tungsten Carbide

At present, 50 to 60% of the world's tungsten is used for the manufacture of tungsten carbide. Among them, rock drills in mining tools, three-cone drills in oil extraction, and coarse-grain tungsten carbide used in the hobs of tunnel shield machines account for a considerable part of tungsten carbide.

coarse-grained tungsten carbide image

As the main product of tungsten resource consumption, tungsten carbide can be used as the raw material to synthesize tungsten carbide directly. The tungsten carbide particles can greatly shorten the smelting process, and the ultra coarse grain tungsten carbide particles are widely used in mine rock drilling tools, which have higher added value than the general tungsten carbide.

Some scholars have proposed a method for preparing coarse grained tungsten carbide directly from tungsten ores. The main process is as follows:

Synthetic scheelite was synthesized from pure sodium tungstate and calcium chloride. Spare after drying.

According to the mass ratio of 33:43:8:9:7 to weighing artificial scheelite, reduced iron powder, graphite powder, alumina and silica, the vacuum induction furnace is placed in the vacuum induction furnace, the vacuum degree is less than 10Pa, the 30min is heated to 1600 ℃, and the heating is kept for 1 hours. After natural cooling, the crucible is removed from the induction furnace.

The slag phase and the metal phase are removed from the crucible, then the two phases are separated and the metal phase is removed. The 1:1 hydrochloric acid is added until the metal phase is completely dissolved, and the tungsten carbide is enriched at the bottom of the container.

The WC powder was separated from the solution, washed with water, and then concentrated with hydrochloric acid to remove impurities. After repeated washing, the purified tungsten carbide powder was obtained after drying.

The new method is made of tungsten ore as the main raw material, which is accomplished by reduction of carbonization at high temperature. The molten iron is melted and formed into a metal molten pool. Tungsten enters the molten iron and forms tungsten carbide with its carbon (tungsten is reduced to form tungsten carbide; raw carbon is used as reducing agent to reduce the oxide of tungsten, and tungsten carbide is formed with tungsten). The calcium in the ore will form slag with raw material alumina and raw material silica, and the impurity enters into the slag phase. After rinsing after acid leaching, the coarse grain tungsten carbide particles from several microns to several hundred microns can be obtained. It has low impurity content, complete crystalline form and complete carbonization. It can be used in the production of hard alloy and has great competitive potential.

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Bismuth Tungstate Photocatalysis for Marine Oil Sewage

With the development of shipping industry, marine and river water pollution caused by ships is becoming more and more serious. Some researchers have proposed a scheme of photocatalytic treatment of ship oil sewage by pre separation + fine filtration + deep oxidation.

bismuth tungstate photocatalysis for marine oil sewage image

(1) The oil sewage from the upper part of the tank is pumped into the direction of the upper entrance of the pool in tangential direction, forming a rotating flow, which is divided into a cylindrical type. Under the action of the centrifugal force of water, the oil particles with relatively small relative density converge to the central part of the pool and float up, so that the coarse oil particles are separated out in advance.

(2) Through the pre separated oily sewage into the fine filter, the fine filter is in turn from top to bottom, including overflow trough, filter material partition board, biomass filter layer, filter material bearing layer, filter material separator with pore size less than biomass filter material, filter material bearing layer is made up of gravel layer, so that raw material filter material is fixed on filter material separator and filter. Between the bearing layer, the pre separated oily sewage is brought to the overflow slot, and then the filter material is removed, the biomass filter layer and the filter material bearing layer are passed in order to realize the filtration and removal of the fine oil particles.

(3) The oily sewage is filtered into the deep oxidation unit and the deep oxidation unit is coated with bismuth tungstate photocatalyst. When the ozone is attached to small oil particles and emulsified oil particles with micro bubbles, the air flotation oxidation pool is entered with the flow of water. The floating of oil particles is realized through the buoyancy effect of ozone bubbles, and the oil particles are initially oxidized and degraded at the same time. The light ceramsite with the visible light catalyst of bismuth tungstate floating on the surface of the water, and the light source is irradiated. The energy transition produces a strong oxidizing free radical in the water, and further catalyzes the oxidation degradation of the floating oil particles. The flotation, ozone oxidation and photocatalytic oxidation are carried out in the flotation cell to achieve the separation and degradation of the remaining small oil particles and emulsified oil particles and sewage.

The three stage treatment process of "pre separation + fine filtration + deep oxidation" of marine oil sewage can simultaneously complete the separation and deep degradation of oil in oily sewage. It has the advantages of good separation effect, high purification efficiency, low labor cost and convenient operation.

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The Algae Pollution Treatment by Bismuth Tungstate Porous Material

A large number of domestic sewage and industrial waste water are discharged into rivers and lakes, resulting in eutrophication of water bodies, affecting the safety of water and living environment. The algae outbreak will cause the oxygen depletion in the water to lead to the death of the fish. The toxins released by some algae will poison the organisms. We should deal with the algae pollution quickly and effectively. It is an urgent need to control the water pollution.

algae pollution treatment by bismuth tungstate porous material image

At present, algae removal in water is often done by manual removal, and the treatment efficiency is low. Researchers have developed a new method for purifying algae: magnetic nanomaterials using solid phase, montmorillonite with porous materials as adsorbents, non-toxic and harmless adsorbents, adsorbents for algal porous materials and bismuth tungstate, a photochemical agent used to degrade algae and algae toxins. The method of scheme preparation is as follows:

(1) First, the adsorbents are evenly dispersed in water and then placed in a water bath reaction tank, through nitrogen protection, and then FeCl3•6H2O and FeCl2•4H2O are put into the water bath reaction tank with the molar ratio of 2:1. The mass ratio of adsorbents to magnetic nanomaterials is controlled in 1:0.4-1.4, and the temperature of water bath is controlled at 60°C -90°C. After mixing 15-30min, the ammonia water with a mass fraction of 30% was added, the pH value of the solution was controlled to 11-13, and the reaction for 2-4h was continued, and the unassembled magnetic nanomaterials and adsorbents were removed.

(2) The compound magnetic adsorbent is prepared with the adsorbent. The compound magnetic adsorbent and the bismuth tungstate photocatalyst precursor are added to the hydrothermal reactor. The mass ratio of the compound magnetic adsorbent and the bismuth tungstate is controlled in the 1:3, the hydrothermal method is at 160 -220°C, and the reaction is 10-24h. The magnetic adsorbent was loaded with light catalyst, and then cooled to room temperature after the reaction was completed. After washing and magnetic separation, the magnetic adsorbent and bismuth tungstate photocatalyst were loaded on the magnetic nanomaterials, and the magnetic compound alga removal agent was obtained by drying the adsorbent and the bismuth tungstate photocatalyst at 60-80°C.

(3) The magnetic compound algae removal agent is added to the eutrophic water containing algae according to the dosage of 0.8- 1.5g/L, stirring for 1-10 minutes, leaving the algae flocculant out for 5-10 minutes, and using magnets to remove the algae flocculant out of the water. The quality of the magnetic compound algae removal agent is better than that made of the algae, and the algae removal agent can adsorb and flocculate the algae and water. Pollutants such as nitrogen and phosphorus, improve the transparency of water, and purify the water quality.

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It Can Change Color? Unveil the Hidden Properties of Tungsten Oxide

At present, the market of electrochromic technology is quite extensive. Most of the electrochromic glass windows are made by applying translucent indium tin or fluoride tin oxide film to two pieces of glass to obtain electrical conductivity, and then apply electrochromic tungsten oxide to one of the glass, and then glue two pieces of glass together with a kind of glue like electrolyte.

electrochromism image

Electrochromic materials are divided into inorganic materials and organic materials. Inorganic materials can be divided into metal oxides and covalent metal complexes. The representative material of metal oxide is tungsten trioxide (WO3). The principle of discoloration is mainly that the energy of the inorganic material falls within the energy range of the visible light region, so when the valence of metal oxide changes, it can just cover the visible light area, reflect the color we see in the naked eye, and some special tungsten oxide derivatives. The compounds even possess bipolar characteristics of redox. In addition to tungsten oxide, the common covalent metal malocclusion is Prussian blue (Prussian Blue), and its principle is that absorption energy under different valence changes the absorption spectrum of the material itself.

The hidden function of tungsten oxide is expected to be applied in the field of new energy batteries. Recently, a high capacity and fast charge electrochromic battery has been developed. The battery is positive and negative with tungsten oxide (W18O49) nanowires and metal aluminum. It can establish an interface with users to identify the capacity by color change. When the state is transparent, the quantity of electricity is full, and the color gradually turns blue to mark the consumption of storage electricity, and the electricity is exhausted when the color is the deepest. The pool can be quickly charged by adding a trace of hydrogen peroxide, or using an external power supply to recharge and use the oxygen in the air to self - charge. The battery is more than 6 times as high as the same battery. This technology can change and improve the details and quality of life around us.

Electrochromic battery is a new type of battery which combines battery technology and electrochromic technology. It has unique color change characteristics. It can show the capacity of battery by the difference of its own color. A kind of interface is established between the user and the battery. However, electrochromic cells are facing many challenges at the present stage, and their capacity, charging time and cyclic stability are not ideal, but there is no doubt that electrochromic cells have an unlimited market potential.

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Lithium Ion Battery Used Nano Tungstic Acid Price on SEPT.16, 2022

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