How is Sodium Metaaluminate (11138 - 49 - 1) produced?
Sep 04, 2025
Sodium metaaluminate, with the CAS number 11138 - 49 - 1, is a crucial chemical compound widely used in various industries. As a reliable supplier of 11138-49-1 Sodium Metaaluminate, I am delighted to share the detailed production process of this important substance.
Raw Materials
The production of sodium metaaluminate mainly starts with two primary raw materials: aluminum hydroxide (Al(OH)₃) and sodium hydroxide (NaOH). Aluminum hydroxide is a white, crystalline powder that can be obtained from bauxite through the Bayer process. Bauxite is the most common ore of aluminum, and the Bayer process involves digesting bauxite in a hot, concentrated sodium hydroxide solution to dissolve the aluminum oxide, followed by precipitation of aluminum hydroxide.
Sodium hydroxide, also known as caustic soda, is a strong base. It is commercially produced by the electrolysis of sodium chloride solution in a process called the chlor - alkali process. In this process, an electric current is passed through a sodium chloride solution (brine), which results in the production of sodium hydroxide, chlorine gas, and hydrogen gas.
Reaction Principle
The chemical reaction for the production of sodium metaaluminate is based on the reaction between aluminum hydroxide and sodium hydroxide. The reaction equation is as follows:
Al(OH)₃ + NaOH → NaAlO₂ + 2H₂O
This is a typical acid - base reaction, where aluminum hydroxide acts as an amphoteric hydroxide, capable of reacting with a base. When aluminum hydroxide reacts with sodium hydroxide, it forms sodium metaaluminate (NaAlO₂) and water.
Production Process
Preparation of Reactants
Before the reaction, the raw materials need to be properly prepared. Aluminum hydroxide is usually purified to remove impurities such as silica, iron oxide, and titanium dioxide. This purification process may involve washing, filtering, and calcination steps. Sodium hydroxide is prepared as a concentrated solution. The concentration of the sodium hydroxide solution is carefully controlled, typically in the range of 20 - 50% by weight, depending on the specific production requirements.
Reaction Step
The reaction between aluminum hydroxide and sodium hydroxide is carried out in a reactor. The reactor is usually made of corrosion - resistant materials such as stainless steel or enamel - lined steel to withstand the corrosive nature of the sodium hydroxide solution.
The aluminum hydroxide and sodium hydroxide solution are added to the reactor in a specific ratio. The reaction is exothermic, which means it releases heat. Therefore, proper cooling systems are required to maintain the reaction temperature within a suitable range, usually between 80 - 120°C. Stirring is also necessary to ensure uniform mixing of the reactants and to promote the reaction.
The reaction time depends on various factors such as the reaction temperature, the concentration of the reactants, and the stirring speed. Generally, the reaction takes several hours to complete. During the reaction, the aluminum hydroxide gradually dissolves in the sodium hydroxide solution, and sodium metaaluminate is formed.
Filtration and Purification
After the reaction is complete, the reaction mixture contains sodium metaaluminate solution along with some unreacted raw materials and impurities. Filtration is carried out to remove the solid impurities. A filter press or a vacuum filter can be used for this purpose.
The filtered sodium metaaluminate solution may still contain some trace impurities. To further purify the solution, processes such as ion exchange or precipitation can be employed. Ion exchange involves passing the solution through an ion - exchange resin, which can selectively remove certain ions. Precipitation methods may involve adding specific reagents to precipitate the impurities, which can then be removed by filtration.
Concentration and Drying
The purified sodium metaaluminate solution can be either sold as a liquid product or further processed into a solid product. If a solid product is desired, the solution is concentrated by evaporation. The evaporation process is carried out under controlled conditions to avoid the decomposition of sodium metaaluminate.
After concentration, the concentrated solution is dried to obtain solid sodium metaaluminate. Spray drying is a commonly used method for drying sodium metaaluminate. In spray drying, the concentrated solution is sprayed into a hot air stream, and the water evaporates rapidly, leaving behind solid sodium metaaluminate particles.
Quality Control
Throughout the production process, strict quality control measures are implemented. The quality of sodium metaaluminate is mainly evaluated by parameters such as purity, concentration, and particle size (for solid products).
Purity is determined by chemical analysis methods such as titration, atomic absorption spectroscopy, or inductively coupled plasma - mass spectrometry (ICP - MS). These methods can accurately measure the content of sodium metaaluminate and the levels of impurities.
The concentration of the sodium metaaluminate solution is measured by density measurement or titration. For solid products, the particle size is measured using techniques such as laser diffraction.
Applications of Sodium Metaaluminate
Sodium metaaluminate has a wide range of applications in different industries.
Water Treatment
In the water treatment industry, sodium metaaluminate is used as a coagulant aid. It can react with water - soluble impurities such as heavy metals and suspended solids, causing them to coagulate and settle out of the water. This helps in the purification of drinking water and wastewater treatment.
Paper Industry
In the paper industry, sodium metaaluminate is used as a sizing agent. It can improve the strength and water - resistance of paper by reacting with cellulose fibers in the paper pulp.
Production of White Carbon Black
Sodium metaaluminate is also used in the production of Sodium Metaaluminate for White Carbon Black. White carbon black, also known as precipitated silica, is an important industrial material used in rubber, plastics, and coatings. Sodium metaaluminate is used in the precipitation process of white carbon black to control the particle size and structure of the silica particles.
Production of Titanium Dioxide
In the production of Sodium Metaaluminate for Titanium Dioxide, sodium metaaluminate is used as a surface treatment agent. It can improve the dispersion and stability of titanium dioxide particles, which is crucial for the performance of titanium dioxide in applications such as paints, plastics, and cosmetics.
Contact for Procurement
If you are interested in purchasing high - quality sodium metaaluminate (CAS 11138 - 49 - 1), please feel free to contact us for further discussions. We are committed to providing you with the best products and services to meet your specific needs.
References
- Kirk - Othmer Encyclopedia of Chemical Technology.
- Ullmann's Encyclopedia of Industrial Chemistry.
- Handbook of Chemical Processing Equipment.