Use Fumed Silica as Anti-sedimentation Agents
Gold is a high-quality hedge hedging tool, favored by investors. Especially in recent years, with the increasing instability of the world economy, gold has become one of the preferred asset allocations of investors because of its functions of hedging and fighting inflation.
Earlier, the worsening situation in Ukraine sent gold prices soaring to a two-year high of $2,070 an ounce. But gold, along with other commodities, fell back last week as conditions changed and bulls took profits, hitting a low of $1,895 an ounce. Rising gold prices may also have an impact on the fumed silica prices.
According to China Business News, Goldman Sachs raised its gold price forecast in early March, considering Asian buyers' gold consumption demand, investment demand and central bank gold purchase demand continue to rise. Three -, six - and 12-month targets were raised to $2,300, $2,500 and $2,500 an ounce, respectively, from $1,950, $2,050 and $2,150. The last time all three accelerated was in 2010-11 when gold prices rose nearly 70%.
The World Gold Council has also noted that global gold demand is at its highest level in nearly two years, which is linked to a recovery in consumption and consumer sentiment to combat inflation.
Fumed silica is a kind of inorganic nanomaterial with a small particle size, large specific surface area, and high surface activity.
It is mainly used as a rheological auxiliary agent in paint and coating, which can effectively prevent flow hanging and thick edges in the construction process and improve construction efficiency.
In addition, silica in the coating is also used as an anti-sedimentation and dispersant aid, can effectively prevent the sedimentation of the pigment delamination, improve the coating weather resistance, scratch resistance, and the bonding strength between the coating and the substrate.
Fumed silica is an ideal anti-sedimentation agent, its hydrogen bond structure is very stable and uniform, and it is a three-dimensional network structure, which is very effective to prevent the precipitation of pigment in the coating system. Especially for the color paste system, the appropriate amount will greatly improve the stability of color paste, and can reduce the amount of wetting dispersant, to improve the applicability of color paste and reduce the influence of color paste on the coating system. At the same time, the anti-sedimentation effect of fumed silica is very beneficial to the storage of coatings, especially some pigments such as metal powder and thin sections, which are easy to precipitate and cannot be completely suspended, the use of fumed silica can ensure that its dispersion does not precipitate.
The precipitation of fumed silica is very beneficial for coating storage and transportation. For some pigments, such as metal powder and thin film, it is easy to precipitate and cannot be effectively suspended. The use of fumed silica can ensure that the mixture is uniform and does not cause sedimentation. In absolute non-polar liquid phase, such as hydrocarbons (hydrocarbons) without hydrogen bond (chemical structure such as R-H) bonding ability, halogenated hydrocarbon (halogen and hydrocarbon electrophilic addition or substitution reaction) solvent, the viscosity recovery time is only a fraction of a second; Thixotropic recovery in polar liquids, such as hydrogen-bonded amines (R-NH3), alcohols (R-OH), carboxylic acids (R-COOH), aldehydes (R-CHO), and dialcohols (such as Ho-Rh2-OH, where R- is a saturated alkyl group), can take up to several months, depending on the amount of fumed silica added and the uniformity of mixing. The fumed silica is pre-dispersed and added to the finished paint. Usually, a high-speed dispersing machine or three-roller machine is used to improve the dispersion effect. If the dispersion is not good, the paint film will have particles, affecting gloss and aesthetics.
In addition, as an anti-sedimentation agent, fumed silica is added to coppery acrylic resin conductive coating. The test proves that it can make the thermoplastic acrylic resin thixotropic and prevent the deposition of filler particles, but if the addition amount is too much, the coating becomes a gel state, the conductivity of the coating would be reduced.
In the powder system, because of the small particle size and high surface energy, silica can be adsorbed on the surface of the coating powder, and form a surface layer on the surface of the powder to improve the dispersion of the powder. In the same coating system, the addition of fumed silica can obviously shorten the dispersion time and improve the production efficiency.
The addition of fumed silica in wall coating can effectively prevent coating from hanging, improve the flatness of the construction surface, and also greatly improve the washing resistance and aging time of exterior wall coating. The bonding strength of coating film and the wall is also greatly improved, the hardness of coating film is significantly increased, and the surface self-cleaning ability is also improved.
The adsorption of fumed silica on the surface of powder coating can form a movable layer and produce a "ball bearing" effect, which can prevent the powder coating from absorbing moisture and agglomerating and improve the fluidity of powder coating.
The main function of floor paint is the rheological control, improving the weatherability and scratch-resistance of floor paint, and improving the leveling performance of the coating.
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According to Reuters, U.S. Treasury officials said they would discuss with G7 leaders pricing caps and tariffs on Russian oil as an alternative to the embargo, which would keep the market supplied, limit price spikes, and reduce Russian revenues.
The EU foreign ministers' meeting was held in Brussels. The meeting failed to agree on the sixth round of sanctions, including an oil embargo on Russia, because of objections from Hungary.
EU High Representative for Foreign Affairs and Security Policy said at a press conference after the meeting, that the meeting failed to reach an agreement on the final adoption of the sixth round of sanctions, the permanent representatives of member states to the EU will continue to discuss. The foreign ministers faced similar difficulties trying to reach an agreement on an oil ban. He said Hungary's position was based on economic rather than political concerns.
Hungary is highly dependent on Russia for energy, getting more than 60 percent of its oil and 85 percent of its natural gas from Russia.
A few days ago, the European Commission submitted the sixth round of proposed sanctions against Russia, including a total ban on Russian oil imports by the end of this year. Hungary immediately objected and said it wanted substantial compensation from the EU to offset its loss from giving up Russian oil.
The fumed silica price is predicted to increase in the next few days, due to geopolitical factors.