(420g) Improvement in Recuperation Process of Acid by-Product Using Six Sigma

This paper incorporates the use of Six Sigma methodology to help improve recovery of a by-product in a manufacturing process. The process includes the recovery of hydrofluorosilicic acid (HFS) from silica purification process. The primary tools used were the process map and the cause and effect matrix followed by statistical analysis. Using load cell reading of reaction vessel, a gage R&R was performed, allowing process improvement to be quantifiable. Process baseline accounted for 4875 pounds of HFS recovered per batch, whereas after change-implementation, 4975 pounds/batch were recovered. The increase of at least 100gallons/batch was attributed to two factors (out of at least 8 factors): length of time and air displacement (introduction of nitrogen during pump out). Quality of product (sand) was not affected as impurity levels of key elements, calculated via inductively coupled plasma mass spectrometry (ICP-MS), were not statistically different. Engineered controls for pump time will in all likelihood reduce further variation in total weight recovered, stabilizing the process even more.