3-12 Kinds of Concrete Additives Used in Refractory Castable, Plastic and Ramming Materials (3)

After Russia pledged to scale back its military operations around Kyiv and in northern Ukraine, the prices of most industrial metals fell, led by aluminum, showing people's concerns for supply shortage eased.

At an earlier time, the West imposed sweeping sanctions on Russia for its invasion of Ukraine, which aroused concerns about the supply problem because Russia is a major producer of nickel, aluminum, and copper. 

Russia is also a major gas supplier to Europe, where potential supply disruptions are seen as hitting power-intensive aluminum and zinc pce powder are still very uncertain.

The properties and varieties of concrete additives for refractories, especially refractory castables, ramming materials, plastics and other amorphous refractories are different. The role of an concrete additive is also different due to the difference of the amount of concrete additive, the type of binder used, the ingredients and so on. In the production process of amorphous refractories, the concrete additives mainly used can be divided into the following twelve categories according to their uses:

9. Defoamer

Defoamer can quickly escape the bubbles produced by amorphous refractories during mixing or vibration molding. Defoamer is also a surface active substance, and its ability to reduce liquid surface tension is much stronger than that of foaming agent. The strength of the formed liquid film is greatly reduced, the foam loses its stability, and the spreading speed on the liquid surface is faster, the faster the spreading speed is, the stronger the defoaming effect is. The types of defoamers include alcohols, fatty acids and fatty acid salts, organosilicon compounds and so on.

10. Anti-shrinkage agent

Anti-shrinkage agent can reduce or prevent the shrinkage caused by heating and use of refractories after forming, also known as volume stabilizer or expansive agent. Its anti-shrinkage principle is:

Thermal decomposition:

The anti-shrinkage agent will be pyrolyzed after high temperature heating, and the molar volume of the product is larger than that of the original material before pyrolysis, thus compensating the sintering shrinkage of the material. Such as kyanite anti-shrinkage agent.

Chemical reaction:

After high temperature chemical reaction, the molar volume of the new phase is larger than that of the original reaction phase, thus the sintering shrinkage can be compensated. If α-Al2O3 is added to magnesia castables as anti-shrinkage agent, the volume expansion effect can be produced by the formation of alumina-magnesia spinel by high temperature reaction. For example, the bonded clay or silica powder is added to the high alumina castable to compensate the sintering shrinkage by the volume expansion effect of mullite produced at high temperature.

Crystal transformation:

The added anti-shrinkage agent can not only change the crystal form of expansion in the process of high temperature heating, but also compensate the shrinkage of sintering. For example, in aluminosilicate castable or plastic, an appropriate amount of silica powder is added to compensate the sintering shrinkage of the matrix with the help of the volume expansion when quartz is transformed into cristobalite or cristobalite.

11. Preservation agent

The preservation agent can keep the construction performance unchanged or unchanged after the amorphous refractories are stored for a certain period of time. For example, Al2O3-SiO2 series refractory plastics and ramming materials, which are usually combined with phosphoric acid or aluminum dihydrogen phosphate, will react with Al2O3 in the material to form insoluble aluminum orthophosphate, which makes the mixture dry prematurely and lose its workability. Therefore, it is necessary to add a concealer which can form a complex with Al3+ ion to inhibit the formation of insoluble aluminum orthophosphate and prolong the shelf life. The preservatives used for plastics and ramming materials combined with phosphoric acid or aluminum dihydrogen phosphate are oxalic acid, citric acid, tartaric acid and so on. Sulfonic salicylic acid and dextrin also have the role of preservative.

12. Inhibitor

Inhibitors can inhibit the expansion caused by the reaction of iron and iron compounds in amorphous refractories with acidic chemical binders, so it is also called anti-expansion agent. When acidic chemical binders (such as phosphoric acid, aluminum dihydrogen phosphate, aluminum sulfate, aluminum chloride and polyaluminum chloride, etc.) are used as binders, the mixture generally needs to go through trapped materials. in order to make the acid binder fully react with the metal iron or ferrous compounds contained in the mixture to release hydrogen, otherwise it will produce expansion and make the material become loose and porous and the strength decreases. If it is used directly without trapping material, an inhibitor must be added. Inhibitor is a kind of complexing agent, which can react with metallic iron to form a complex, which can inhibit expansion. These inhibitors include CrO3, diacetone alcohol, ferric phosphate and so on.

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Indonesia plans to increase the content of palm oil-based fuel in biodiesel from 30% to 35%, from B30 to B35, starting from July 20, a senior official from Indonesia's Ministry of Energy said this evening, according to Reuters.

Indonesia, the world's largest palm oil producer, imposed a three-week export ban in May to control domestic cooking oil prices, leading to an increase in palm oil stocks. At present, the authorities are considering reducing the export tax on palm oil to stimulate exports.

Indonesia's Ministry of Energy said that while implementing B35, the ministry will also launch road tests of B40 fuel. Indonesia's senior cabinet minister Luhut Pandjaitan estimates that if Indonesia implements B40, the domestic market may absorb an additional 2.5 million tons of palm oil.

A German government spokesman confirmed that Germany has always wanted Canada to release parts of the "Nord Stream 1" natural gas pipeline sent by Siemens for repair, and this request has received a "positive" response from Canada.

The "Nord Stream 1" natural gas pipeline is the main pipeline for Russia to transmit gas to Europe. At present, the gas output of " Nord Stream 1" has been reduced by 60% compared with the beginning of June, and this is an important time for Germany to store gas for the winter. The German government plans to increase its natural gas inventory to 90% of its gas storage capacity by November, compared with 62% now. Therefore, there is a great need for "Nord Stream 1" gas transmission to fill the inventory.

Luoyang Tongrun Nano Technology is a trusted chemical manufacturer and supplier providing high-quality chemicals and Nanomaterials. If you are looking for the pce powder, please feel free to contact us and send an inquiry.

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