Multi-element analyzer

Multi-element analyzer is a key instrument used for determining the chemical composition of metal materials such as steel and iron. It is widely applied in industrial and mining enterprises, including metallurgy, mining, machinery, foundry, chemical industry, research institutes, and technical quality supervision departments. These analyzers come in various types, such as computer multi-element analyzers, microcomputer high-speed analyzers, metal multi-element analyzers, carbon-sulfur analyzers, infrared carbon-sulfur analyzers, and ore element analyzers. Among them, carbon-sulfur analyzers are particularly popular. This article will focus on the combustion method used to determine carbon and sulfur content, highlighting the role of additives in this process.

Types of Commonly Used Additives

The combustion method for analyzing carbon and sulfur typically involves several common additives, such as Sn, Cu, Fe, CuO, V2O5, Cr2O3, SiO2, SnO2, Si, W, Mo, MoO3, WO3, B2O3, and others. The choice of additive varies depending on the combustion system. For example, high-frequency furnaces usually use tungsten particles, electric arc furnaces often use iron powder and silicon-molybdenum powder, while tube furnaces may employ tin particles. In some cases, special or composite additives like TH-100 are used for specific test samples. High-frequency furnace combustion may also involve composite additives containing tin, which can enhance the efficiency of the analysis due to their unique properties.

The Role of Additives

Additives play a crucial role in the combustion process. One of their primary functions is to act as a flux, lowering the melting point of the sample so that it can be fully melted and allow gases like CO2 and SO2 to escape. Iron, for instance, has a melting point around 1529°C, and at temperatures below 1500K, it is difficult to melt completely. By adding a flux, the melting point is reduced, enabling the proper release of these gases.

Another important function is the heating effect. Some additives, such as metals and non-metals, can generate heat when oxidized in an oxygen stream, increasing the overall temperature of the furnace—especially beneficial in electric arc furnace combustion.

Additives also help adjust the acidity and alkalinity of the medium. Since CO2 and SO2 are acidic oxides, an alkaline environment can hinder their release. By adding the right amount of acidic additives, the medium becomes neutral or slightly acidic, promoting gas release, especially for SO2, which is highly sensitive to pH changes.

Stirring is another critical function. Additives like SiO2 can improve the mixing within the molten material, accelerating the diffusion of sulfur ions and enhancing the oxidation reaction. Some additives produce gas when heated, creating a stirring effect as the gas escapes.

Catalytic effects are also significant. For example, copper oxide (CuO) can capture carbon and sulfur during combustion, facilitating the formation of CO2 and SO2. Additionally, additives like CuO can act as catalysts, speeding up the reaction process.

Stabilizing combustion is another benefit. In electric arc furnaces, unstable burning can occur, but adding small amounts of tin or silica can help stabilize the process.

Some additives also have anti-interference properties. After combustion, substances like FeO3 and SnO2 may form dust that adsorbs SO2, leading to lower test results. Adding appropriate additives can prevent this adsorption and reduce interference.

Finally, additives can participate in chemical reactions, further influencing the accuracy and reliability of the analysis.

There are many types of multi-element analyzers, each playing a vital role in various industries. Their application in carbon and sulfur analysis is especially widespread. Understanding the importance of additives in the combustion method is essential for accurate and efficient testing. This brief overview aims to provide useful insights into the role of additives in carbon and sulfur determination, helping professionals make informed decisions in their analytical processes.