Activated silica is made through a carefully controlled process that modifies the structure of sodium silicate.
According to the provided reference, the creation of activated silica involves several key steps:
- Neutralization: The process begins by partially or completely neutralizing the alkali of a dilute sodium silicate. This crucial initial step is necessary to initiate the formation of tiny silica particles, known as micelles.
- Aging: Following neutralization, the mixture undergoes aging. During this period, the silica micelles are allowed to grow in size. This controlled growth is essential for achieving the desired properties of activated silica.
- Dilution: Finally, the mixture is subjected to diluting. The purpose of this step is to effectively stop the further increase in the size of the micelles. If the growth were allowed to continue unchecked, it would lead to the undesirable formation of a gel.
In essence, activated silica production is a process of controlled polymerization starting from sodium silicate, where the growth of the resulting silica particles is initiated by neutralizing the alkalinity and then halted at a specific point through dilution before gelling occurs.
Steps to Make Activated Silica
Based on the reference, the process can be summarized as follows:
- Prepare Dilute Sodium Silicate: Start with a dilute solution of sodium silicate.
- Neutralize Alkali: Add an acid (like sulfuric acid or carbon dioxide) to partially or completely neutralize the alkali content. This triggers the formation of initial silica micelles.
- Age the Solution: Allow the solution to age for a specific time. This permits the micelles to aggregate and grow to a certain size. The aging time is critical and depends on the desired properties.
- Dilute the Solution: Add water to dilute the solution. This action significantly slows down or stops the growth of the silica particles, preventing them from linking up extensively enough to form a rigid gel structure.
This controlled approach ensures the formation of discrete, reactive silica particles suspended in solution, which is characteristic of activated silica.
