Gypsum, also known as calcium sulfate hydrate, is a naturally occurring mineral found in layers of sedimentary rock all over the world. It is formed by the evaporation and replenishment of waters containing calcium and sulfates.
You can find more information on our web, so please take a look.
White or gray in color, gypsum can be ground into a fine powder and boiled until the majority of its moisture is removed — a process known as calcination. Adding the water back to this powder creates a pliable substance that can be formed into a shape or mold and will harden to hold that form, or the substance can be added to other materials to bind them together.
Because of its binding abilities, gypsum is a primary ingredient in some toothpastes. It is also used as plaster to create surgical casts; as an additive in many foods, like canned vegetables, ice cream and tofu; and as an amendment, conditioner and fertilizer for agricultural applications.
Other uses of gypsum include:
Although gypsum plays an important role in our lives and is found in many of our homes, food and hygiene products, many people do not know much about this mineral or even that it exists at all. Here are some lesser-known facts about this mineral that is a mystery to many.
Before the era of computer generated imagery, early Hollywood filmmakers used a number of substances to create fake snow on set, including cotton, cornflakes and soap flakes. They also used shaved gypsum to mimic the look of real snow.
But snow isn’t the only role gypsum has played on the silver screen. One of its recurring roles is in the creation of movie sets.
Since gypsum is common in the production of sidewalks, it stands to reason that the mineral may have been cemented in the Hollywood Walk of Fame. The stars are made of terrazzo, which is composed of marble chips, granite, quartz or glass and poured on a concrete base. Concrete is often bonded with Portland cement so that it can harden, and gypsum is an element in Portland cement.
When the Egyptians learned that gypsum could be made into plaster by grinding it up and adding water, they used it everywhere inside their palaces, pyramids and tombs. As it still holding up thousands of years later, gypsum proves to be a durable building material.
The name “gypsum” is derived from the ancient Greek word “gypsos,” which means plaster. The ancient Greeks used a form of gypsum in the windows of their temples because of the moonlight effect it created on the altars when the sun shone through. The ancient Greeks named this form of gypsum “selenite” after their moon goddess, Selene, and the name has stuck all these years.
Benjamin Franklin was the one of the first people in the United States to use gypsum. He called it “land plaster” and put it to work on his farm to condition the soil. This land plaster is still used in agricultural applications today to provide a source of plant nutrition, to improve the structure of the soil and to reduce runoff, among other benefits.
The walls and ceilings of many houses are covered with drywall because it is both easy to install and simple to finish with a coat of paint. But drywall, which is made of gypsum plaster, offers another benefit to homeowners besides ease of decorating – it offers protection in the event of a fire.
Because gypsum contains water, it will not heat past 212° F should a fire occur in the home. The water in the gypsum will be released as steam and the drywall will remain at 212° F until all the water has evaporated out. Although gypsum is not fireproof, it will protect the structure of the house from damage for a period of time.
Gypsum in its natural state is an ore often found layered with limestone. It is liberated from its natural state most commonly by surface mining. To get the gypsum ore into a state where it can be sold for its many uses, it is crushed to size using DDC-Sizers, Feeder-Breakers, Hammermill Crushers, Jaw Crushers or Roll Crushers and stockpiled to await further processing.
A McLanahan DDC-Sizer.
The crushed gypsum is screened using Vibratory Screens to separate the sizes for their different uses. One size from the screen may be sold as a cement retarder, while another size may be stockpiled for further processing. Further processing includes drying the ore to remove excess moisture, then grinding it into a fine powder known as land plaster. The land plaster is collected in a Hydrocylcone, discharged onto a conveyor and stockpiled for sale as a soil conditioner.
To create stucco, the land plaster is heated with hot gasses either directly in a flash calciner or indirectly in a kettle calciner to remove much of the chemically bound water. The stucco can be further ground and mixed with retarders to create plasters, or it can be mixed with dry additives, water, shredded paper, accelerators and soap foam; spread in a mold; and dried in a kiln to create wallboard.
The next time you are sitting in your home, playing a game of tennis, brushing your teeth, washing your hair or even just walking down the sidewalk, think about how all these items are possible because of a little known mineral called gypsum.
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS
FIRST NAME
*
LAST NAME
*
*
MESSAGE
*
ADDITIONAL DETAILS
Thanks. We have received your request and will respond promptly.
Log In
Are you an
Engineering professional?
Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.
Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Eng-Tips Posting Policies
Gypsum/Plaster Factory
thread995-360841 Forum Search FAQs Links MVPsForum
Search
FAQs
Links
wuxing contains other products and information you need, so please check it out.
MVPs
(Chemical)
(OP)
4 Mar 14 04:04I have been working in this factory for a few months now. I am a fresh graduate. so by all means I do not have any authority what so ever. The factory produces about 30k sqm of boards per day. what really irritates me is that the "superior" people here are using sqm/minute.
I have never seen this in my time studying. I have never seen area flow rate. please guide me as I do not really have much experience.
Feel free to ask any questions, and if you really would like to help me we could communicate further into the problem.
(Chemical)
4 Mar 14 06:33Sqm/minute seems reasonable to me. Just because you have not seen sqm/minute in a textbook does not make it meaningless. The factory needs a way to measure and communicate the productivity that makes sense to everyone. Simple and direct is best. Sqm/minute seems a logical choice.Are all of the boards the same width, or are various width boards made from time to time?
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
(Chemical)
(OP)
4 Mar 14 06:48well depending on the production plan. currently they are on the 1200mmX2400mmX12.5mm. they do have other boards such as the 1220mmX1830mmX12.5mm. All I could think about is that if they are planning to produce the 9mm or the 7mm, the amount of additives should also be different, is it not?
they only increase some of the additives which are introduced to the mixer manually. the mixer is set only at 9.5 tons per hour and cannot be increased further.
what I think I should be doing is redo the calculations on a volumeteric flow rate, as in cubic meter per minute.
(Chemical)
4 Mar 14 07:24
What problem are you solving, and how will it make the owners more money?
Matt
(Chemical)
4 Mar 14 08:01Ah ha! Length, width, and thickness vary! Does density change too?
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
(Chemical)
4 Mar 14 08:16Would a concept like board foot be useful? It's really a measure of volume.
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
(Chemical)
(OP)
4 Mar 14 08:37@mbt22, the CEO of the company is an old wise man. let's just say he is a family friend. the more I tackle a problem the more I make the CEO happy. thus, my parents happy. and there's nothing like the feeling of your own family being proud of you. even though it's a minor issue. but small things matter over here in the Middle East. and as a Chemical Engineer I feel like it's my job to tackle such issues. I do not really want to get too personal on this. but you asked and I answered.
@Latexman the slurry density does vary from 1.15-1.22 kg/m3(I'm not sure if it's the right unit they use). I doubt that they do this precisely. they are using a plastic cup, then weight it, then divide the weight over the plastic cup's capacity. it may sound experimentally fine but the percentage of error here I have to say is between 5% to 15%(human error, cup not properly handled, etc)
(Chemical)
4 Mar 14 10:09I'm sorry, I meant the density of the finished boards. Is the density of the finished boards changed on purpose to meet different specifications?
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
(Civil/Environmental)
4 Mar 14 11:21You are working with a product that is sold on a unit basis of square meters. Why should that trouble you that the production machinery is rated on the basis of square meters per minute.
A simple spreadsheet program can easily convert the production capacity of square meters per minutes to determine the raw materials requirements in units of kg/sec.
(Chemical)
(OP)
5 Mar 14 01:23@latexman no, the density does not matter whatsoever in the final product.
@bimr fair enough, but different compositions have different effects on the board. let's say the moisture level, the bonding of the board, the flexural strength. lots of factors can get affected due to variation of the consituents, is it not?
they are not sold on a unit basis of sqm. they are sold on a unit basis of number of boards or stack. each stack has 62 boards. so it does not matter if the production units is sqm or kg/sec.
if, for example we were producing papers. then the sqm/min does not bother me. but the boards have a certain thickness and it varies from board to board.
(Chemical)
5 Mar 14 03:34Sorry AliZK, I should have been clearer. Making a change costs money, even if it is in peoples time to think about it and understand what it is. If there is an existing way of doing things that gets product out the door, meeting the spec and everyone understands what is meant, why change?
If there is a shortcoming of the current method - perhaps a fraction get the wrong amount of additives, or you can't easily measure margin because you don't know the volume of raw materials - then the shortcoming that you are trying to rectify should tell you the what measurement you should be using.
Matt
(Civil/Environmental)
5 Mar 14 10:56Production machinery is customarily rated in unit capacity.for example, consider a bottling machine in a food plant. Production rating = bottles per minute.Food machinery is rated in bottle per minute despite the fact that the food content varies with production run and the product is delivered in case or pallet loads.Your plant is making gypsum board in M2 quantities. Rating production in cases per year, pallets, stacks etc. does not make any sense when each pallet may contain different quantities, each board may be a different size, width etc.The common denominator in production capacity is the M2 produced.
Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.
Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.
Click Here to join Eng-Tips and talk with other members! Already a Member? Login
Contact us to discuss your requirements of gypsum board manufacturing plant. Our experienced sales team can help you identify the options that best suit your needs.