Displaying items by tag: Japan

Japan: Taiheiyo Cement plans to build a 75MW biomass plant at its Ofunato cement plant in Iwate prefecture. The new unit will burn both domestic and imported biomass fuel. The new power plant will replace units damaged at the site during the earthquake in 2011. As such Iwate prefecture has decided there would be no requirement for a new environmental assessment.

Sri Lanka: Tokyo Cement has resumed importing clinker from Japan. The clinker will be used to make the producer’s NIPPON-PRO branded cement.

"We at Tokyo Cement having identified the demand for a high performance cement tied up with a leading Japanese manufacturer to import clinker with high specifications," said Dashantha Udawatte, Group Marketing Manager at Tokyo Cement.

Tokyo Cement operates a 2.4Mt/yr cement grinding plant in Trincomalee.

Japan: Sumitomo Osaka Cement's operating profit rose by 14% year-on-year to US$83m in the April – September 2015 period, according to Reuters. Its sales rose by 3.7% to US$937m and its net profit rose by 84.8% to US$62.4m.

We report on development from Japan this week with the creation of a low-alkali cement for use at nuclear waste sites. Professor Katsuyoshi Kondo, Joining and Welding Research Institute at Osaka University, and Nippon Steel & Sumikin Cement Co have prepared a process that mixes silica dioxide extracted from rice chaff with cement.

As press reports explain, the team has developed technology to extract highly purified silica with numerous holes measuring 5 – 7nm in diameter by washing rice chaff with organic acid and burning it. The surface area of the silica extracted from rice chaff is 50,000 - 90,000 times larger than that contained in existing cements, enhancing the reaction between silica and calcium hydroxide and thus lowering the alkaline level.

The stated application for this new research is for underground nuclear waste disposal sites. At these locations extremely high durability is required for long periods of time, potentially for tens of thousands of years.

Normally the concern with alkali-silica reactivity is between alkali in the cement and a sensitive aggregate over a shorter time period. Under high moisture and high alkali content the resulting concrete can crack leading to reduced-performance. However, the issue with nuclear waste storage is that it has to be stored underground and for long periods of time. This means that the cement can potentially react with groundwater producing calcium hydroxide making the groundwater alkaline. This can then react with aggregates in the clay and bedrock at the storage site. Clearly this is undesirable for a long-term storage site of hazardous materials.

In the wake of the Fukushima disaster, this kind of development will be of high interest in Japan. It will also have applications around the world wherever radioactive waste sites are built.

One example of the demanding construction conditions facing builders in these environments is the original sarcophagus used to encase the Chernobyl Nuclear Power Plant reactor in 1986. Building it used more than 7,000t of steel and 410,000m³ of concrete. Erected in a hurry under horrendous conditions, the container was never sealed properly and the structure was only given a design lifespan of 20 to 30 years. Currently a replacement, New Safe Confinement, is being built at a projected cost of Euro2bn for completion in 2017. The structure will be up to 100m tall and 165m long with a lifetime of at least 100 years.

One of the issues raised in the documentary film 'Into Eternity' is what exactly should one daub on the entrance to a long-term waste dump? Given that the Onkalo spent nuclear fuel repository in Finland is planning to stay sealed for 100,000 years, how should its planners communicate to people, who potentially rediscover it in the future, that they should stay away? One suggestion quoted here is to put Edvard Munch's The Scream on the door. However, we have difficulty today in reading and interpreting Ancient Egyptian writing and art from 5000 years ago. What this means for any of our descendants unlucky enough to stumble upon a buried nuclear waste site is anyone's guess. At the very least though using a low-alkali cement that will last as long as possible is a good start.

Japan: Osaka University and a cement company in Hokkaido have co-developed a low-alkaline cement that uses rice chaff to strengthen the durability of final nuclear waste disposal sites, according to Kyodo News.

The cement is essential for the construction of final nuclear waste disposal facilities that need a durability of up to 100,000 years to prevent harm from radioactive materials. In such repositories, nuclear waste is solidified with glass and placed in metallic containers before being covered with clay and buried underground. If normal cements are used underground, they react with groundwater to produce calcium hydroxide, making the groundwater highly alkaline. This causes cracks and deterioration in the clay and bedrock at the facility.

To lower the alkaline levels in cement, professor at Osaka University's Joining and Welding Research Institute, Katsuyoshi Kondo, and Nippon Steel & Sumikin Cement Co mixed silica dioxide extracted from rice chaff with cement. The silica reacts with calcium hydroxide and weakens alkaline.

The team has developed technology to extract highly purified silica with numerous holes measuring 5 – 7nm in diameter by washing rice chaff with organic acid and burning it. The surface area of the silica extracted from rice chaff is 50,000 - 90,000 times larger than that contained in existing cements, enhancing the reaction between silica and calcium hydroxide and thus lowering the alkaline level.

Japan is looking for a place to build a final repository for the highly-radioactive nuclear waste generated from power plants. In Finland, a disposal site for high-level radioactive waste is already under construction. "We aim to utilise the low-alkaline cement at facilities abroad after repeated tests to verify its performance," said a Nippon Steel & Sumikin Cement official.

Japan: In the April - June 2015 period, Sumitomo Osaka Cement's operating profit rose by 26.8% year-on-year to US$35.5m. Its sales rose by 6% to US$455m, according to Reuters.

Japan/Singapore: Taiheiyo Cement, which operates a cement terminal in Singapore through Singapore Cement Manufacturing (SCMC), a joint venture with Singapore-based Hong Leong Asia Ltd, has completed a new 24,000t cement silo at SCMC's cement terminal in Singapore.

Infrastructure investment, including subway and highway construction, is driving the robust cement market in Singapore and fuelling demand for low-heat-type cement as a way to prevent thermal cracking in concrete structures with large cross-sections (so-called mass concrete).

Coinciding with the construction of SCMC's new silo, Taiheiyo Cement has developed a new type of cement specifically formulated to satisfy Singapore's local needs. The new export-oriented product, which is manufactured using Portland cement and admixture ingredients such as fly ash from coal-fired power plants, qualifies as type CEM II as defined by Singapore's cement quality standard (SS EN 197-1). The new cement has greater resistance to thermal cracking due to its low-heat and low-shrinkage characteristics, higher long-term strength, improved workability and lower alkali-silica reactivity. It is also certified under the Singapore Green Labelling Scheme (SGLS) and therefore carries a Green Label in recognition of its environmental friendliness, which was demonstrated during a series of tests carried out with the cooperation of local users and experts. SCMC also used the new cement in the construction of its new silo and in the process verified its performance.

Taiheiyo plans to manufacture the product using fly ash that has been selected, formulated and managed with the cooperation of domestic Japanese power companies. It is expected to contribute to the effective use of fly ash from newly-built coal-fired power plants in Japan. Going forward, SCMC plans to use the new silo for CEM II, complementing its Ordinary Portland Cement and expanding its business through the supply of new cement that meets local needs.

The 'revelation' this week that South Korean cement producers have been paid US$127m to use/dispose of Japanese coal that is thought to be radioactive certainly sounds scary. If it is true that cement made with contaminated coal has led to the construction of radioactive buildings and roads, this may have prised open a 'can of worms' for coal producers, exporters and cement players alike. According to local media, four South Korean firms - Ssangyong Cement, Tongyang Cement, Lafarge Halla Cement and Hanil Cement - received the money to use the coal between March 2011, when the Fukashima nuclear power plant started to leak radiation, until 2013. A total of 3.7Mt of cement is 'under suspicion.'

Caesium-137 is formed by fission reactions that start with uranium-235 in nuclear reactors. The Fukushima reactor that started leaking in 2011 used this type of fuel. Once it leaked, caesium-137 was deposited into the sea and onto the land, presumably also making its way into nearby coal deposits.

As it is a metal with a melting point of just 28.5°C and a boiling point of 671°C, the caesium-137 would vaporise if it were to enter a cement production line operating at 1450°C as a metal. However, caesium will not enter the cement-making process as a metal due to its rapid and explosive reaction with water. An interesting slow-motion of this reaction can be seen here.

Instead, caesium will enter the cement-making process either as its oxide or a simple salt (e.g.: caesium chloride) in the coal. The salt will be ionized in the heat of the flame, sending caesium ions into the kiln and thus direct contact with the clinker as it is being formed. Here it will become part of the matrix of the clinker and hence the final cement product. All the time the caesium-137 is radioactive.

And it stays radioactive once it is in the finished product, for example in a building or road surface. Its half-life, the time that it takes for half of the caesium-137 to decay to meta-stable barium-137 (emitting radiation as it decays), is unfortunately very well matched to the life-span of concrete buildings at 30.7 years. This means that after about 100 years of building life the building would still be around 10% as radioactive as it was when it was built.

This would certainly be a problem if the coal was highly contaminated. However, a few questions come to mind. Firstly, if the coal contains 20-73 becquerels per kilogramme (Bq/kg) of caesium-137, as has been claimed by Lee In-young, an opposition spokesman for the New Politics Alliance for Democracy party and member of the National Assembly's Environment Labour Committee, why is this a problem when the Japanese legal limit for eating caesium-137 in contaminated vegetables is all the way up at 500Bq/kg? When the most dangerous mechanisms of caesium-137 poisoning relate to accumulation in soft tissue, how can driving along a caesium-137-containing highway constitute a health risk?

Also, the coal may well start the cement making process with 25-73Bq/kg of caesium-137 but the clinker will have a lower level. This is because for every 1t of clinker the plant will typically consume just 100-200kg of coal. The caseium-137 and hence the radiation will therefore be spread out over a larger mass. A level of 50Bq/kg in the coal would translate to a clinker level of 5-10Bq/kg. This is around 100 times lower than the Japanese vegetable limit. After this, the clinker is extended with additives to make cement. This is then added to aggregates and / or sand when concrete or mortars are made, further diluting the caesium-137, perhaps to as low as 1-5Bq/kg. It is arguable that South Korea has received a higher caesium-137 dose from Japan via air and sea than via coal imports.

In light of all this, it appears that those calling for investigations on scientific grounds, like Lee, may be misguided. However, there may be political gain. The histories of Japan and South Korea are long, violent and distrustful. Indeed, according to a BBC World Service poll conducted earlier in 2014, South Korea and China jointly have the most negative perceptions of Japan of all world nations. In this environment stories about radioactive coal become much easier to believe in.

In reality the Japanese vegetable limit is well above the likely levels that might be found in any cement products resulting from the use of this coal. It is consistent with EU limits set more than 20 years earlier (600Bq/kg). A search on the US Environmental Protection Agency's website fails to bring up any formal limit. Instead it states that everyone is exposed to caesium-137 from atmospheric fallout to a low level and that the most dangerous cases are where waste metal processors unwittingly come across sources.

So on the surface then, the South Korean reaction seems like a storm in a teacup. One question remains though. If the caesium-137 levels in the coal are so much lower than the Japanese vegetable limit, why are Korean firms being paid to take it out of Japan?

Japan: eRex Inc, a power generation company, has agreed to invest US$159m in a biomass power project situated in the premises of Taiheyo Cement plant in Oita Prefecture, Japan. The total installed capacity of the power plant will be 50MW, sufficient to supply 100,000 households. The investment/MW will be US$3.18m. The power plant will use palm shells, a by-product of palm oil production in Indonesia and elsewhere, as its primary fuel. The company will set up a separate storage facility in Oita to hold 100,000t of palm shells. The power plant is expected to be operational in 2016.

Japan/China: Japan’s Taiheiyo Cement has dissolved a joint venture agreement with Xinjiang Tianye in Xinjiang, Chinese in response to Chinese government efforts to reduce excess capacity in the sector.

Taiheiyo Cement Investment, the company’s Chinese arm, signed the agreement with Xinjiang Tianye in December 2012. After receiving government approval, they set up a joint venture in April 2013, planning to produce 1.2Mt/yr of cement. However, in 2013 Beijing increased measures to curb investment in the cement industry to counter overcapacity. This cast doubt on whether the venture could build production facilities as planned. With the business environment for the region's cement industry worsening, Taiheiyo and Xinjiang Tianye opted to end the agreement.