Silica fume, còn được biết là microsilica, is produced as a by-product during the manufacturing process of silicon metal and ferrosilicon alloys, which are widely used in applications such as silicons, chế tạo chip máy tính, aluminum and steel production, và nhiều hơn nữa.

While these materials are incredibly important in industrial applications, their by-product silica fume plays a crucial role in the concrete industry. At Henan Superior Abrasives Import & Công ty xuất khẩu, Ltd., we supply silica fume or microsilica of various grades and concentrations. Continue reading to learn more about different micro silica fume grades and how they are used.

Silica Fume Overview

Before we dive into the differences among silica fume grades and their properties, let us have a quick refreshment of what silica fume is.

Silica fume, còn được gọi là microsilica, or volatilized silica, presents a pozzolanic material. The silica fume material looks like grey powder, quite similar to fly ashes or Portland cement. Silica fume consists mostly of amorphous or non-crystalline Silicon Dioxide (SiO2), with particles around 100 nhỏ hơn nhiều lần so với hạt xi măng trung bình.

Whenever natural properties of concrete need to be modified, silica fume can be added to concrete during batching, making concrete very durable and considerably stronger.

Silica Fume Properties

To summarize, the main properties of microsilica include:

• Size: The dimensions of silica fume particles are considerably smaller than that of cement particles. Each particle of silica fume is less than 1 đường kính micromet, with the average diameter being approximately 0.15 micromet. Như vậy, each microsilica particle is approximately 0.01 the size of a cement particle.
• mật độ lớn: Silica fume’s bulk density can range between 130 và 800 kg/m3, depending on the degree of the densification of the material.
• Trọng lượng riêng: Specific gravity describes the ratio of the substance’s density to the density of a standard reference. The specific gravity of silica fume can range between 2.2 và 2.3.
• Reaction time: Khi thêm vào bê tông, silica fume does not start reacting immediately. Thay thế, it remains inert for a short period of time. When the Portland cement and silica fume are combined, the process of mixing, or hydration, begins. During this hydration, two primary chemical compounds are produced: calcium hydroxide and calcium silicate. While calcium hydroxide doesn’t affect the properties of cement, calcium silicate hydrate leads to increased strength and durability.

Silica Fume Classification and Grades

Silica fume is classified into different grades and types based on its density, sự tinh khiết, and particle size. The price, hiệu suất, price, and applications of various grades are also different.

1. According to SiO2 Concentration

While many international standards require microsilica to have Silicon Dioxide or SiO2 content of at least 85%, the standard can range from country to country. Nói chung, silica fume can be subdivided into five categories based on its SiO2 content:

• SiO2 above 85%, with an average value above 88%. This type controls the loss of ignition, vì thế, is used for low-grade refractories and concrete.
• SiO2 above 90%, with an average value of 92%. This grade can be used in general refractory materials and bê tông to control related impurities by customer’s requirements.
• SiO2 above 92%, with an average value of 94%. This silica fume grade finds applications in medium- và high-grade refractories and involves specific requirements for fluidity.
• SiO2 above 94%, with an average value of 95%. This silica fume grade is produced from Zirconia and is white in color.
• SiO2 above 99%, with an average value of 99.5%.

At Henan Superior Abrasives Import & Công ty xuất khẩu, Ltd, we supply silica fume or microsilica with SiO2 content ranging from 85% đến 99%.

2. By Material Fume Density

In addition to CO2 concentration, silica fume can be divided into four groups based on its density:

• Original state. The density of silica fume in the original state ranges between 100-170 kg/m3. In this original state, silica fume bonds easily but is difficult to transport.
• Mild encryption. Mildly-encrypted silica fume has the density of 200-250 kg/m3. At this state, the material consists of no particles, with significantly easier transportation. Tuy nhiên, mildly-encrypted microsilica is still unstable under the influence of temperature.
• Semi-encryption. Semi-encrypted silica fume has a density of 250-350 kg/m3. At this density, numerous loose particles start to appear, which are not easy to bond. Tuy nhiên, the ease of transportation is significantly improved.
• High-density. Cuối cùng, high-density silica fume has a density of 550-750 kg/m3 and consists of mainly hard particles of different particle sizes and compactness. High-density microsilica is easy to transport.

Between these four groups, silica fume is often further classified into densified and khói silic không đông đặc.

Khói silica đậm đặc

Khói silica đậm đặc, or DSF, refers to dry densified silica fume with bulk density of 550-750 kg/m3. This type of microsilica is ready-to-use and produces incredibly durable, high-strength concrete with low rebound shotcrete and very low permeability.

Recommended Uses

DSF is recommended for use wherever shotcrete or high-performance concrete is required. Higher strengths reduce erection, production, and transportation costs, as well as column sizes, thus ensuring that new structural designs are possible. thêm vao Đoa, microsilica concrete produced with DSF has lower chloride permeability, making it highly suitable for bridge decks, cấu trúc bãi đậu xe, và công trình biển.

DSF allows for the production of dense, less permeable concrete, which is ideal to solve the problem of industrial floor deterioration in aggressive environments. When used in shotcrete, DSG increases overhead buildup and reduces rebound.

Properties of Densified Silica Fume

At Henan Superior Abrasives Import & Công ty xuất khẩu, Ltd, we offer several grades of densified silica fume, classified as Grade 85D, Grade 90D, Grade 92D, and Grade 96D. DSF is available with the following properties:

• Appearance: dark-grey powder
• Trọng lượng riêng: 2.2-2.3
• mật độ lớn: 550-750 kg/m3
• Hàm lượng SiO2: 85%-96%

Khói silica không tăng cường

While the chemical composition of densified and undensified silica fume is exactly the same, there are some important differences in their tính chất vật lý.

When silica fume is produced, it is smelted by a high-temperature electric arc furnace and collected in the form of undensified silica fume. This undensified silica fume is referred to as the “original ash,” as it is the initial state of microsilica. This type of silica fume is incredibly light, có mật độ 250-350 kg/m3, rất tích cực, và yêu cầu một không gian lưu trữ lớn.

Recommended Uses

Undensified silica fume is commonly used in pre-bagged products, such as repair mortars and grouts. Tuy nhiên, it is not widely used for concrete production due to its high price caused by the inconvenience involved with storage and transportation, along with lower demand.

Properties of Undensified Silica Fume

Tại Nhập khẩu chất mài mòn cao cấp của Hà Nam & Công ty xuất khẩu, Ltd, we offer several grades of undensified silica fume, classified as Grade 85U, Grade 90U, Grade 92U, Grade 96U, and Grade 99U. Undensified silica fume is available with the following properties:

• Appearance: dark-grey powder
• Trọng lượng riêng: 2.2-2.3
• mật độ lớn: 250-350 kg/m3
• Hàm lượng SiO2: 85%-99%

By Particle Size or Specific Surface Area

Hơn nữa, silica fume can be classified by the size and surface area of the particle:

• Median diameter of 0.3um. Most silicon powders in the world belong to this category, with almost all particle sizes falling under 1um, and the specific surface area of 15-25 m2 / g.
• Median diameter under 0.1um. This type of silica fume is typically found in high-purity silicon powders and is relatively rare. The specific surface area is usually more than or equal to 30m2/g.
• Median diameter of 0.5-2.0um. This type of microsilica has a specific surface area of 5-15m2/g and is also rare.
• Median diameter above 2.0um. Larger particle sizes are incredibly rare and lead to poor performance.

It is important to choose the appropriate type of microsilica powder according to the actual needs and required applications, which will lead to better results and more economical outcomes.

By Silica Fume Application

Hôm nay, microsilica is used in numerous industries, bao gồm vật liệu chịu lửa, chất dẻo, đất sét, vật liệu điện tử, chất kết dính, cao su silicone, đúc chính xác, và nhiều hơn nữa. Silica fume có thể được chia nhỏ hơn nữa dựa trên ứng dụng của nó:

• Vật liệu chịu lửa. Silica fume thường được sử dụng trong đúc, thiêu kết, và vật liệu chịu lửa hợp nhất. Ví dụ, nó có thể được sử dụng trong hiệu suất cao, cao cấp, và vật liệu đúc chịu lửa xi măng thấp và các bộ phận đúc sẵn, gạch thấm không khí, hào và muôi sắt quy mô lớn, và nhiều hơn nữa.
• Vữa và bê tông. Silica fume cũng có thể được sử dụng cho các bến cảng, các tòa nhà cao tầng, cầu đường sắt, đập hồ chứa, đường bê tông, và nhiều hơn nữa.
• Các lớp bảo vệ. Nano-silica sol đóng vai trò như một vật liệu tích cực để chống cháy, bảo vệ môi trương, và lớp phủ chống ăn mòn.
• Tường và vật liệu trang trí. Silica fume cũng có thể được sử dụng cho vữa cách nhiệt, vữa polyme, và như một tác nhân giao diện cho cách nhiệt tường.
• bột trét. Microsilica có thể được sử dụng trong bột bả để cách nhiệt tường bên ngoài và bên trong.
• Làm đầy và gia cố. Nó cũng được sử dụng làm vật liệu làm đầy và gia cố trong nhựa, cao su, tẩy, sơn, polyester không bão hòa, và nhiều hơn nữa.
• chất phụ gia. Cuối cùng, silica fume thường được sử dụng làm chất phụ gia trong các lĩnh vực hoạt động khác.

Choose Among Numerous Silica Fume Grades Available at HSA

Silica fume finds applications in a wide range of industries, and it is incredibly important to choose the right microsilica grade with the desired properties. may mắn thay, tại Nhập khẩu chất mài mòn cao cấp Hà Nam & Công ty xuất khẩu, Ltd., we supply microsilica of various grades and concentrations. Shop high-quality silica today.