Displaying items by tag: Pozzolana Portland Cement

Spain: Residents of Cartagena, Murcia, have protested Cemex’s plans to begin mining pozzolan at new sites locally. The Murcia Plaza newspaper has reported that the protestors are calling for a mining ban, in line with their interpretation of the area’s Rural Area of Special Environmental and Social Sensitivity designation.

France: Cem'In'Eu has launched FUSIOCIM, a CEM II/C pozzolan cement, that offers a 43% reduction in CO₂ emissions compared with ordinary Portland cement (OPC). FUSIOCIM has specific CO₂ emissions of 506kg/t. It is suitable for various concrete applications and comes in 25kg bags.

Cem’In’Eu general manager Fabien Charbonnel said "We created Cem’In’Eu with the ambition of reducing the carbon footprint of the cement industry. And we are proving it today with a low-carbon offer that easily replaces traditional cements, without any change for construction professionals. We are convinced that this transition can only be done with pragmatism and taking into account the needs of users.”

India: Birla Corporation has started the kiln at its new 3.9Mt/yr Mukutban cement plant at Nagpur in Maharashtra. The project had an investment of around US$370m and the plant will be run by subsidiary RCCPL. Birla Corporation said that the new plant is the group’s fourth integrated plant and the biggest single cement production line in Maharashtra by capacity. It will be powered by two 20MW captive power plants that use air-cooled condenser technology to reduce water consumption by 90%. The plant was partly built using the group’s MP Birla Cement Perfect Plus product, a Portland Pozzolana Cement, composed of 30 - 35% fly ash, itself a by-product of thermal power plants. Use of fly ash and slag will be scaled up at the site as production ramps up.

“It is no mean feat to complete such a large project under such challenging circumstances with major disruptions on account of Covid-19 which led to several logistical challenges, stoppage of work and a flight of labour from the project site on several occasions,” said Harsh V Lodha, the chair of Birla Group. “Moreover, to achieve 10m man hours of construction with zero accidents and completion of the entire project without a single major accident or fatality, I am told, is a unique achievement in the cement industry.”

Charah Solutions has been steadily building up its fly ash distribution business in recent years with an eye on the supplementary cementitious materials (SCM) market. This week it opened the third of its new series of SCM grinding plants, at Oxnard in California, US. The unit sticks out because it is focusing on grinding natural pozzolans. The plant will receive natural pozzolan by truck and rail and then use Charah’s patented grinding technology to produce pozzolan marketed under its MultiPozz brand. The previous plants in this series mentioned natural pozzolans but this is the first to promote it explicitly.

The change is potentially telling because global demand for granulated blast furnace slag (GBFS) outstrips supply. Both performance benefits and environmental regulations are pushing this. It’s a similar situation for fly ash, also driven by trends to close coal-fired power stations in some countries. As Charles Zeynel of SCM trading firm ZAG International explained in the March 2019 issue of Global Cement Magazine, “...volcanic pozzolans are a potential SCM of the future. This is gaining traction, but it’s slow progress at the moment. This will be the answer for some users in some locations.”

The problem though is that natural pozzolans are down the list of preferred SCMs for their chemical properties after silica fume, GBFS and fly ash. The first is expensive but the latter two were traditionally cheap and easy to obtain if a cement or concrete producer had access to a source or a distribution network. Natural pozzolans are very much subject to variations in availability.

It’s no surprise then that Charah is promoting natural pozzolans in a Californian plant given that state’s environmental stance. It’s unclear where Charah is sourcing their pozzolan from but they are not the only company thinking about this in the US. Sunrise Resources, for example, is working on the environmental permits for a natural pozzolan mine near Tonopah in Nevada. As it described in its company presentation, California and Nevada are the most affected states in the fly ash supply crisis because they are, “...at the end of the line when it comes to rail deliveries from power stations in central and eastern USA.” It also estimated that California used 0.9Mt of pozzolan in its cement production of which about 90% is fly ash. The state produced 9.6Mt in 2015. Other companies are also mining and distributing natural pozzolans in the US as the website for the National Pozzolan Association (NPA) lists. Although, if this line-up is comprehensive, then the field is still fairly select. Most of these companies are based in the west of the country.

One last thing to consider is that various groups are tackling a potential future lack of SCMs for the cement industry by making their own pozzolanic materials through the use of calcined clay. These groups include the Swiss-government backed LC3 project and Cementir’s Futurecem products. Using clay should bypass the supply issues with natural pozzolans but the cost of calcining it requires at the very least an investment to get started.

As concrete enthusiasts often point out, a variant of pozzolanic concrete was used by the Romans to build many of their iconic structures, some of which survive to the present day. To give the last word to the NPA, “What is old is new again: natural pozzolan is back!” If environmental trends continue and steel and coal plants continue to be shut then it might just be right.

Nigeria: Ogbonnaya Onu, the Minister of Science and Technology, has inaugurated a pozzolana cement plant at Bokkos in Plateau state. The plant is currently being commissioned, according to the News Agency of Nigeria. The 5000t/yr grinding unit is intended to produce low cost cement. It consists of six sections: materials handling; grinding; nodulisation; calcination; milling; metering; and bagging. The plant is being run in conjunction with the Nigerian Building and Road Research Institute (NBBRI).