Process Parameters Optimization of Silica Sand Nanoparticles Production Using Low Speed Ball Milling Method

Experiments are designed using Taguchi method to find the optimum parameters for silica sand nanoparticles production using low speed ball milling. Orthogonal array and signal-to-noise ratio are applied to study performance characteristics of machining parameters which are the ball to powder weight ratio, volume of milling jar, and rotation speed. Results obtained from signal-to-noise ratio analysis showed that ball to powder weight ratio is the most influential parameter. 1. Introduction Nanoparticles of silica sand have been researched progressively and produced due to the unique features as a result of size reduction. Silica sand nanoparticles have proved to be a very effective additive to polymers by improving durability, strength, and flexibility. Nanosilica is also used as an additive to improve strength and workability of self-compacting and high performance concretes. Nanosilica particles are widely produced by chemical processes. However, chemical synthesis of nanosilica produces high contamination in the final products. As the demand is increasing for higher nanosilica purity, contamination is expected at the minimum level. Other than chemical synthesis, other processes such as precipitation, vaporization at high temperature, sol-gel process, high speed vertical rotating mill, and planetary ball mill are among the most commonly used methods to produce silica sand nanoparticles. The objective of this research is to design a technique of transforming natural Tronoh silica sand to silica sand nanoparticles by using a combination of low speed ball milling and heating processes. It is expected that the technique will be able to produce high purity silica sand nanoparticles of less than 100？nm consistently. Taguchi method provides a simple, efficient, and systematic approach to determine the optimum parameters [1]. Compared to the factorial method, instead of testing all possible combinations of parameters available, Taguchi method provides a more simplified way to set up the combination of experiment parameters. The parameters tested in this paper are ball to powder weight ratio (BPR), volume of milling jar, and milling speed. 2. Parameters Identification There are a lot of parameters used in ball milling process. However, the parameters that have been tested most for optimization are the rotation speed and milling time. This indicates that these two parameters play an important role in determining the effectiveness of the milling. As supported by Simoes, ball to powder weight ratio is recognized as one of the most influential parameters, alongside