VOA科学技术2014--US Company Develops Cement-making Method that Reduces

An American cement maker¹ has developed a technology that it says cuts levels of carbon dioxide (CO2) during production.

The International Energy Agency estimates the cement industry produces about eight percent of the world's total CO2 emissions³.

Cement is one of the main materials used to make concrete, the most widely used building material in the world. Cement makes up about 10 to 15 percent of concrete mixtures. Other materials include sand, small rocks, crushed stone and water.

Cement accounts for about 88 percent of concrete's CO2 emissions. Under current methods, manufacturing one ton of cement produces nearly one ton of CO2.

Cement production involves heating the materials to very high temperatures in a device called a kiln⁴. This part of the process releases CO2. The industry has yet to find an effective replacement⁵ for cement in concrete production.

The California-based cement maker Fortera says it has invented a new method that captures CO2 exhaust coming from the kilns⁶ as cement is made. The captured CO2 is turned into a solid substance and is later put back into the process to make more concrete.

Fortera's chief executive, Ryan Gilliam, spoke⁷ to the Associated Press (AP) about his company's efforts. He said the goal was to develop a less polluting cement production method "that can work really at any plant."

In the beginning, Fortera said its method will reduce CO2 emissions by about 10 percent. The first reduced CO2 product will be produced at a Redding, California plant belonging to cement maker CalPortland. AP reports the product is expected to be available in the first week of May.

Fortera says its method is different compared to other low-CO2 cement products. That is because the company's method could be widely built into existing plants.

Fortera's effort is one of several in the industry that seeks to reduce the possible climate harm of concrete. In the United States, the American Institute of Architects is an industry group for builders. It educates many of the world's top building companies about the dangers of CO2 in concrete.

Some governments, including Vancouver, British Columbia, have established building guidelines urging companies to produce lower-CO2 concrete.

California passed a law in 2021 that requires the state's Air Resources Board to develop plans for the state's cement industry to reduce its CO2 emissions. The targets seek cuts of 40 percent by 2035 and to reach net zero emissions by 2045. Net zero happens when a city or state removes at least as many emissions as they produce.

The First Movers Coalition⁸ is an international organization of more than 90 companies. The group seeks to help establish climate technologies to reduce CO2 emissions. The group announced new policies in 2021 aimed at creating greater demand for low-carbon cement through their market position.

The same year, 40 of the largest cement and concrete manufacturers agreed to use methods to make lower-CO2 concrete by 2050. Part of the agreement called for the development of new CO2-capturing methods.

Mike Ireland is the president and chief executive of the Portland Cement Association, the national trade group that represents U.S. cement manufacturers. He told the AP he thinks the U.S. "has to do what it can to be a leader to help other countries" with their cement-producing methods. "But we have to get the rest of the world, particularly the Global South, as they industrialize to leapfrog some of the technologies we have."

Carbon emissions from cement manufacturing are "an existential threat to the world and for our industry," he said.

Words in This Story

cement - n. a powder substance used in building that is mixed with water and sand to make a hard substance

emission² - n. the act of sending something out such as a gas, heat, or light

concrete - n. a hard substance using in building operations

exhaust - n. gas waste produced by engines and industrial processes

architect - n. a person who designs buildings

leapfrog - v. to improve one's position by going past other people quickly

1 maker   

n.制造者，制造商

参考例句：

• He is a trouble maker，You must be distant with him.他是个捣蛋鬼，你不要跟他在一起。
• A cabinet maker must be a master craftsman.家具木工必须是技艺高超的手艺人。

2 emission   

n.发出物，散发物；发出，散发

参考例句：

• Rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施，降低污染物排放总量。
• Finally,the way to effectively control particulate emission is pointed out.最后，指出有效降低颗粒排放的方向。

3 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

4 kiln   

n.（砖、石灰等）窑，炉；v.烧窑

参考例句：

• That morning we fired our first kiln of charcoal.那天上午，我们烧了我们的第一窑木炭。
• Bricks are baked in a kiln.砖是在窑里烧成的。

5 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

6 kilns   

n.窑( kiln的名词复数 )；烧窑工人

参考例句：

• Bricks and earthware articles are baked in kilns. 砖和陶器都是在窑中烧成的。 来自辞典例句
• The bricks are baking in the kilns. ？里正在烧砖。 来自辞典例句

7 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

8 coalition   

n.结合体，同盟，结合，联合

参考例句：

• The several parties formed a coalition.这几个政党组成了政治联盟。
• Coalition forces take great care to avoid civilian casualties.联盟军队竭尽全力避免造成平民伤亡。