SYNTHETIC GYPSUM BOARD

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Author Message Wayne Yancey Senior Member Username: wayne_yancey Post Number: 928 Registered: 01-2008 Posted on Friday, June 04, 2021 - 11:33 am:    Good morning, Who has experience with "synthetic" gypsum board? Who manufacturers synthetic gypsum board in the USA other than CertainTeed? This I know: Synthetic gypsum is created as a by-product of industrial processing. It is composed of calcium sulfate dihydrate, has the same characteristics as natural gypsum, and is a high-quality and environmentally friendly product. I googled synthetic gypsum board and came up with one processor. FEECO International. FEECO is highly experienced in processing gypsum, both natural and synthetic forms. Thank you. Rosa Cheney Senior Member Username: rdcaia Post Number: 21 Registered: 07-2018 Posted on Friday, June 04, 2021 - 12:54 pm:    I'm in the mid-Atlantic region, and much of the gypsum board manufactured in our region (close to Appalachian coal country) is manufactured with synthetic gypsum, which is a byproduct of the coal flue-gas-desulferization process. The synthetic gypsum counts as pre-consumer recycled content...yay...which means these panels have 90-95% pre-consumer recycled content. I believe the panel products of all the major manufacturers...USG, National Gypsum, American Gypsum, etc, that are manufactured in our region are made primarily from synthetic gypsum. Those same products if manufactured elsewhere in the country might not be. As I understand it, since the chemical composition of the synthetic gypsum is the same as natural, mined gypsum, you are not going to see manufacturers specifically call out which is going into their panel products. You will know by the reported super-high amounts of recycled content, specifically pre-consumer recycled content, in the panel product. ken hercenberg Senior Member Username: khercenberg Post Number: 1376 Registered: 12-2006 Posted on Friday, June 04, 2021 - 12:58 pm:    I recall that some manufacturers used to offer maps showing facilities where synthetic gypsum was made to allow designers to tap into the regional materials credit and the recycled credit. I'm not sure but LEED has possibly changed criteria to allow one or the other but not both. If that's an issue you'll want to confirm that. Funny that eliminating coal-fired plants will increase mining and destruction of habitat to provide gypsum again. Seems like we just can't win. John Bunzick Senior Member Username: bunzick Post Number: 1848 Registered: 03-2002 Posted on Friday, June 04, 2021 - 02:44 pm:    Ken, I was just thinking the same thing about the closing of coal powered power plants. It will be interesting to watch how this progresses. Dave Metzger Senior Member Username: davemetzger Post Number: 799 Registered: 07-2001 Posted on Friday, June 04, 2021 - 03:46 pm:    Yes, John and Ken, I feel gypped. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 951 Registered: 10-2007 Posted on Sunday, June 06, 2021 - 03:03 pm:    Does the ability to sell the waste from coal powered power plants make them more economically viable and thus less likely to be replaced? The same thing happens with respect to the use of fly ash in concrete. ken hercenberg Senior Member Username: khercenberg Post Number: 1377 Registered: 12-2006 Posted on Sunday, June 06, 2021 - 03:59 pm:    Its one of those tradeoffs that happen often in our industry. As far I know there are already sacrificial locations in the US and Canada (see Ft. Dodge, Iowa) abundant in natural gypsum that can be readily mined without having to destroy other areas that our society may want to protect (think White Sands National Park). With the advent of electric transportation perhaps this will be considered more sustainable than the current options that allow more regional manufacture. Of course as long as we need coal-fired plants to generate that electricity, making this discussion moot, I don't know exactly how everything gets factored in. That is for greater minds than mine to assign values to. Somehow these aspects of sustainability tend to be glossed over. I started getting vilified back in the 90's when I asked about this so I stopped. I guess they are inconvenient truths. John Bunzick Senior Member Username: bunzick Post Number: 1849 Registered: 03-2002 Posted on Monday, June 07, 2021 - 03:54 pm:    I don't know to what extent that the sale of FGD gypsum makes a coal plant more profitable, but I suspect that this would be a minor decision on whether a plant is going to be closed. The big one is cost of generation of power. Also, only some coal plants have gypsum plants nearby. My understanding is that the FGD gypsum is not really shipped out, but tends to be used in a neighboring drywall factory. Does anyone have these details? Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 608 Registered: 10-2003 Posted on Monday, June 07, 2021 - 06:47 pm:    The source for info is American Coal Ash Association. I used to be active in the fly ash industry and my sense was recycling of ash is viewed as a regulatory compliance issue and a cost center, not a profit center. It takes equipment to capture the particles in the flue gases, then the particles have to be "beneficiated" or graded and processed. The motivator, in all but the most enlightened coal companies, is the rising cost of disposal due to regulation. Not sure if distance to gypsum board plant makes a big difference. The coal trains leave the power plants empty and can easily take ash to market. But hey, what do I know. I was just a shil for a company processing supplementary cementitious materials and then for several companies that were using ash in concrete products. I remember a time when it was customary for specs to require virgin material and prohibit coal combustion products. Times change. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Guest (Unregistered Guest) Unregistered guest Posted on Tuesday, June 08, 2021 - 02:12 pm:    We might already be back to a time when virgin gypsum is more desirable than FGD gypsum. Apparently the captured sulfur dioxide from coal-fired power plants also contains mercury which is then released when processed into FGD gypsum. I haven't run across any project teams that are really keying in on this, but I have had it brought to my attention by the sustainability people in my office as something they are worried about. It wouldn't surprise me if on a project they asked me to require minimal pre-consumer recycled content to control for this, or to simply require no synthetic gypsum. Note that natural gypsum also contains mercury, but the plants producing FGD gypsum have higher mercury emissions. More information here: https://healthybuilding.net/blog/553-selecting-the-wrong-drywall-could-introduce-mercury-into-the-environment Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 610 Registered: 10-2003 Posted on Tuesday, June 08, 2021 - 04:15 pm:    There is a flaw in the Healthy Building analysis. FGD gypsum board does not introduce Hg into environment. That happens when coal is burned. My guess is that the Hg in gyp board does not migrate to the surface and poses little if any danger to building occupants. People cutting the material should wear respirators anyways. BTW, fly ash also contains some Hg. Should we stop using that, as well, even though it significantly reduces carbon emissions associated with portland cement? Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Guest (Unregistered Guest) Unregistered guest Posted on Tuesday, June 08, 2021 - 07:21 pm:    Perhaps, but I'm not sure you're properly interpreting or understanding the HBN article's analysis. I'm not the expert but I think the issue being raised is that when coal is burned the EPA regulates the amount of mercury that can be emitted from the power plant's flue. So coal plants scrub this, and other regulated substances like sulfur dioxide, from the flue gasses. The main product used for synthetic gypsum, sulfur dioxide (containing some mercury), ends up being sold to the synthetic gypsum board factory where the mercury can end up being volatilized and released through the gypsum board factory's flue without the same EPA regulations requiring it to be removed from the flue gasses. The fact that there is a market for the FGD products for making gypsum means that the coal plants are able to pass the mercury on to another industry that isn't being regulated as stringently. So yes, the mercury is introduced when the coal is mined and burned, but it is ultimately being released to the environment through the gypsum factory's flue. I also might agree with you that it poses little danger to the building occupants or even the worker installing the synthetic gypsum board. The mercury released from the gypsum factory's flue however, is posing a greater potential danger to the environment surrounding the gypsum factory, as well as the surrounding community, and eventually areas downstream and in the food chain due to mercury's persistent bioaccumulation and toxicity. So it might be less concerning that there is mercury in the gypsum board the construction worker is installing, and more concerning that there is the increased amount of mercury in that same worker's tuna fish sandwich they bring for lunch each day. The source for both could have been the synthetic gypsum board factory which can be traced back to the coal. But the coal plant passed the externality on to the gypsum factory who didn't have to control for it and it gets passed on to the rest of us from there. As long as there is a market for it, the industrial chain releasing the toxin will remain. Coal plants being shut down can break that chain. So can increased pressure from consumers to avoid using FGD gypsum. Of course, so could pressure from the EPA to regulate mercury from synthetic gypsum factories. All of this is a wicked problem and I don't know that there is a clear solution. The article even acknowledges that natural gypsum has its issues too. They are advocating for change based on their focus of hazard (in this case mercury) avoidance. Someone else might come to a different conclusion based on other things and it might still be perfectly logical. I simply wanted to point it out because it was a case of where virgin materials are being pushed as a potentially better option and tie it back to the original topic of synthetic gypsum which was being looked at as a "environmentally friendly product" most likely due to the high recycled content, but it can be trickier than that. To be honest, my office is less concerned about whether we are getting natural or synthetic gypsum (most of the time it will be natural based on our project locations), and more concerned with ways that we can reduce it's use in our projects with enhanced products or thinner products where fire resistance or acoustical performance aren't needed. Project teams are thinking more about how they can avoid using 5/8-inch Type X board everywhere and instead be strategic and use thinner products or products with reduced carbon footprints to reduce the project's overall embodied carbon. They've taken the interpretation that reducing carbon overall is more important than worrying about the mercury or pre-/post-consumer recycled content percentages. John Bunzick Senior Member Username: bunzick Post Number: 1852 Registered: 03-2002 Posted on Saturday, June 12, 2021 - 03:52 pm:    I'm interested in how the mercury is volatalized or otherwise released in the manufacture of gypsum board. The drywall plants that I've toured were quite simple. Mined gypsum is ground to the right texture, some cullett (or whatever ground up cut-offs are called) is added, and other ingredients such as fibers are added. The whole lot is mixed with water and spread onto paper spooling off a roll. The material dries/cures along a line several hundred feet long, where it is cut up. I don't know of any process where there ingredients are "purified" or even heated - curing gypsum itself releases heat - whereby mercury would be driven off. I'm not asserting mercury is not released, but there's nothing in the process that would obviously do this; unlike the burning of coal. There had been a related concern about the proliferation of compact fluorescent bulbs, which contain mercury. If they're not recycled, the mercury ends up in a landfill. However, the electricity saved would have spewed more mercury into the atmosphere than that in the bulb. This is all a bit moot now, with the advent of LEDs, not to mention the increase in percentage of power generated by non-coal-burning sources. Guest (Unregistered Guest) Unregistered guest Posted on Monday, June 14, 2021 - 11:48 am:    John, I believe this paper cited in the article addresses your question; "Fate of Mercury in Synthetic Gypsum Used for Wallboard Production," https://www.osti.gov/servlets/purl/943310.