Today’s post is a bit of an egghead post and stems from a question I as asked on Quora. I thought it might be interesting for you more technically oriented readers and those wanting to know more about the wonderful world of water. So here we go.
Hard water presents two different pathways of problems in the electronics industry.
Indirectly – This industry typically needs ultra pure water for chemical preparations and rinse-water. Making this water involves purification technology including RO/DI polishing as the most popular. Calcium causes scaling of RO membranes and other filtration equipment. It requires removal by softening, or elimination through the use of anti-scalants and/or acid to lower the pH and reduce the scale potential. This adds extra steps, complexity and cost to the manufacturing process.
Furthermore, when softening is used, Sodium replaces calcium. Sodium is not rejected as well as calcium by RO membranes, so some of it passes. Sodium is also harder to pick up by ion exchange polishers. So in summary, the indirect problems created by hard water in the electronics industry have to do with increasing process costs and complexity, and leaving sodium to be dealt with. The next section, Direct problems, talks about hardness in process. (I ignored the other minor components of hardness for simplicity, and just focused on calcium, the main component)
Directly – Much of today’s electronic industry is considered micro-electronics. From phones to computers to gaming technology and more, microprocessors, semiconductors and micro-circuit boards are common manufacturing components. Within those items are many microscopic pathways of copper, gold or similar metal that carry electricity to and from the various components. It is vitally important that none of those pathways touch each other or “short out”. If this happens the product will fail. The components of hardness, calcium and magnesium are metals, and as such conduct electricity. If you have ever seen spots on glassware left after rinsing in hard water you have witnessed what would be a major problem for the electronics industry. Those “spots” are metals; calcium and magnesium for the most part. Such a spot deposited over the electronic component will short out the pathways and cause the product to fail. Sodium likewise is a metal, and while it is highly soluble in water, it is still undesirable in the electronics industry.
So there you have it. Hardness creates problems on the pre-filtration side and on the process side of the Electronics industry.