Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Crush those clinkers while they're hot

14.01.2015

Rice University study suggests changes to cement manufacturing will save energy

Making cement is a centuries-old art that has yet to be perfected, according to researchers at Rice University who believe it can be still more efficient.


A cutaway illustration of a clinker, a pellet manufactured in a kiln and then ground to make cement, shows a defect called a screw dislocation. Rice University scientists studied the effect of such defects on the quality of cement used in concrete and how much energy could be saved by modifying the manufacturing process.

Credit: Shahsavari Group/Rice University

Former Rice graduate student Lu Chen and materials scientist Rouzbeh Shahsavari calculated that fine-tuning the process by which round lumps of calcium silicate called clinkers are turned into cement can save a lot of energy. Their new findings are detailed in the American Chemical Society journal Applied Materials and Interfaces.

Manufacturers of Portland cement, the most common type in use around the world, make clinkers by heating raw elements in a rotary kiln and grinding them into the fine powder that becomes cement. Mixed with water, cement becomes the glue that holds concrete together. An earlier study by Shahsavari and his colleagues that viewed the molecular structure of cement noted that worldwide, concrete manufacturing is responsible for 5 to 10 percent of the carbon dioxide, a greenhouse gas, released into the atmosphere.

The researchers analyzed the crystal and atomic structures of five phases of clinkers representing stages of cooling after they leave the kiln. They focused on the internal stresses that make some more brittle (and easier to grind) than others. They also looked at the unavoidable defects called screw dislocations, shear offsets in the raw materials that, even when ground, influence how well the powders mix with water. That reactivity determines the cement's ultimate strength.

They found that clinkers were not only most brittle when hottest, but also the most reactive. In ranking the five samples' qualities, they suggested their research could lead manufacturers to consolidate processes and cut grinding energy that now absorbs around 10-12 percent of the energy required to make cement. Equally important, for each ton of produced cement, the grinding energy accounts for roughly 50 kilograms of carbon dioxide emissions into the atmosphere, they determined.

"Defects form naturally, and you cannot do anything about them," Shahsavari said. "But the more brittle the clinkers are, the better they are for grinding. We found that the initial phase out of the kiln is the most brittle and that defects carry through to the powder. These are places where water molecules want to react."

###

The National Science Foundation supported the research. Shahsavari is an assistant professor of civil and environmental engineering and of materials science and nanoengineering and a member of the Richard E. Smalley Institute for Nanoscale Science and Technology at Rice. Chen is now a structural engineer at Arup.

Read the abstract at http://pubs.acs.org/doi/abs/10.1021/am5091808

This news release can be found online at http://news.rice.edu/2015/01/13/crush-those-clinkers-while-theyre-hot-2/

Follow Rice News and Media Relations via Twitter @RiceUNews

Related Materials

Shahsavari Group: http://rouzbeh.rice.edu/default.aspx

George R. Brown School of Engineering: http://engineering.rice.edu

Images for download: http://news.rice.edu/wp-content/uploads/2015/01/0120_CLINK-1-WEB.jpg

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice's undergraduate student-to-faculty ratio is just over 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is highly ranked for best quality of life by the Princeton Review and for best value among private universities by Kiplinger's Personal Finance.

Media Contact

David Ruth
david@rice.edu
713-348-6327

 @RiceUNews

http://media.rice.edu 

David Ruth | EurekAlert!

More articles from Materials Sciences:

nachricht Scientists channel graphene to understand filtration and ion transport into cells
11.12.2017 | National Institute of Standards and Technology (NIST)

nachricht Successful Mechanical Testing of Nanowires
07.12.2017 | Helmholtz-Zentrum Geesthacht - Zentrum für Material- und Küstenforschung

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Protein Structure Could Unlock New Treatments for Cystic Fibrosis

14.12.2017 | Life Sciences

Cardiolinc™: an NPO to personalize treatment for cardiovascular disease patients

14.12.2017 | Life Sciences

ASU scientists develop new, rapid pipeline for antimicrobials

14.12.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>