How to Dispose of Ferric Chloride from PCBs

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Jul 5, 2022|PCB Maintenance, Repair and Troubleshooting, People and Safety

A major use of Ferric Chloride is PCB etching. It makes copper traces that allow circuit board components to connect. Disposal is always a challenge for users of Ferric Chloride, particularly if the Ferric Chloride is used at home by amateurs making circuit boards.

It is challenging to dispose of Ferric Chloride, primarily when amateur circuit board makers are using it. It cannot be poured down the drain but instead must be neutralized with sodium carbonate (washing water) or sodium hydroxide.

Pouring Ferric Chloride down the drain is not acceptable. To neutralize it, you must neutralize Ferric Chloride with sodium carbonate (washing water) or sodium hydroxide. 

Copper sludge collects at the bottom once the pH is between 7 and 9. Liquid at the top can be skimmed and further diluted with more water. The copper sludge can be disposed of following HAZMAT RULES.

The following is a tutorial on how to dispose of Ferric Chloride safely and effectively.  

Understand the Effects Ferric Chloride Can Have

Is Ferric Chloride hazardous? 

When used correctly, Ferric Chloride is a game-changer. It is a low-cost alternative that makes PCB development and production less expensive and easier to manage. Used incorrectly, however, it can have severe negative consequences. 

Corrosion

Ferric Chloride is exceptionally caustic to piping, storage, and pumping equipment (wastewater applications.) Left undiluted, it can eat through anything on that list. To combat this risk, equipment exposed to Ferric Chloride is usually stainless steel, which Ferric Chloride cannot corrode through. 

Skin and Eye Irritation and Injury

If Ferric Chloride comes into contact with the skin or gets in an eye, it can cause severe burning and, in some cases, blindness. Ingesting Ferric Chloride can severely injure a person and even kill them. Ferric Chloride is also very poisonous to aquatic life. 

Heavy Metals

The production of Ferric Chloride leaves a final product with metals and heavy metals. Metals found in a Ferric Chloride Mixture include but are not limited to Zinc, Manganese, and Chromium. 

Finally, because Ferric Chloride is so toxic, spills become more acute, and handling must be highly regulated. You must not deviate from safety protocols when handling or moving Ferric Chloride. You not only can harm yourself, but you can harm the immediate environment with just a little pause to address the HAZMAT threat.

Wear the Appropriate Attire for Disposing of Ferric Chloride

Staying safe around Ferric Chloride is always challenging because there is minimal margin of error. If you are disposing of Ferric Chloride, you must follow these pieces of advice.

Wear Chemical Worker’s Goggles

If you get Ferric Chloride in your eyes, the best-case scenario is excruciating pain and likely blistering from burns. The worst-case scenario is permanent blindness in the eye Ferris Chloride invades. The answer is to don a pair of “chemical worker’s glasses.”

Chemical workers’ glasses encase your eyes, creating a seal under and on the side of your eyes. Glasses prevent any liquids with Ferric Chloride from getting into your eyes, and they keep out Ferric Chloride powder. Additionally, if any toxic fumes are associated with the Ferric Chloride you are using, your eyes will not be exposed to them.

You should wear your glasses underneath your goggles. Additionally, if you spill any Ferric Chloride, you should keep your goggles on until the Ferric Chloride disposal is completed. You should keep them on because powdered Ferric Chloride can hang in the air for a long time. 

Additionally, you should use a face shield. A face shield will protect you against splashes and prevent you from getting the chemical on your skin. You still have to be careful with the side of your face. Use a face shield in addition to chemical worker goggles.

Wear Chemical Protective Clothes

Ferric Chloride stains fabric, so always wear older clothes you do not care about when handling it. You should also wear clothes covering every exposed part of your body, including:

• Heavier trousers
• Rubber boots
• Long sleeve shirt
• Rubber apron

Wear a Dust Mask or Respirator

A dust mask is a vital piece of clothing when getting rid of Ferric Chloride. The dust particles are extremely fine and can burn any sensitive, exposed areas like the nose, mouth, or eyes. A mask is fine if you are only disposing of a small amount of Ferric Chloride, but if you are disposing of a significant amount, a respirator is recommended.

Wear Appropriate Gloves

Ferric Chloride will burn and blister even though parts of the skin. Because of that, you must wear rubber gloves at all times you are working around Ferric Chloride.

Change the pH Value of the Solution for Disposal

Neutralize the Ferric Chloride Solution with Sodium Bicarbonate

The first step is to mix the Ferric Chloride with Sodium Bicarbonate. Test the mixture constantly. Do not stop adding Sodium Bicarbonate until the pH level reaches between 7 and 8. Do not let the pH level exceed 8, or the solution will emerge too basic.

A substitution for Sodium Bicarbonate is Sodium Hydroxide, or “caustic soda.” It is just as effective as Sodium Bicarbonate. 

Separate the Solid from the Solution

Once you are done mixing, you will have a solution that consists of 2 layers: Copper sludge at the bottom and liquid at the top. Once you are there, follow these steps.

Pour the Liquid Into Another Container

Carefully pour the liquid, keeping as much of the copper sludge in the first container as possible. By separating the liquid from the sludge, three things will happen:

• Reduce the danger of a spill
• Dispose of the liquid down the drain
• The sludge is isolated, reducing the possibility of a spill or splash harming someone

Pour the Liquid Down the Drain

You may be wondering, “Can ferric chloride go down the drain?” The answer to that question is it can, but only after it is neutralized. To do that, separate the second container from the first. Next, add water to the liquid to dilute the Ferric Chloride further and raise the pH level. Once it is diluted with as much liquid as the container will hold, pour all of it (liquid, not sludge) down the drain.

Collect the Copper Sludge

After you have disposed of the liquid, move the copper and iron sludge into a HAZMAT safety disposal receptacle. The bags are specially made to prevent Ferric Chloride from escaping. Then, take the bag for PCB recycling to your local HAZMAT disposal facility.

Final Thoughts

Ferric Chloride is an effective part of the process of PCB etching. Disposing of it, however, is a challenge. But, if you stick to all these rules, you will be safe, and your disposal process will be almost foolproof.