Displaying items by tag: Slag

Cement 2 Zero (C2Z) has officially launched in the UK this week. The project is an industrial scale pilot of the Cambridge Electric Cement (CEC) process. The Materials Processing Institute will lead on this stage with two-year funding of around Euro7m provided by UK Research and Innovation (UKRI). Partners include the University of Cambridge, Atkins, Balfour Beatty, Brewster Brothers, Celsa Group, Day Aggregates and Tarmac.

CEC’s method uses recycled concrete paste in place of lime-flux in steel recycling. Slag is formed as the steel melts and this is then used in place of clinker to make more cement. This way of making cement cuts out the decarbonisation of limestone step from conventional clinker production. If renewably-sourced electricity is used to power the heating and grinding parts of manufacture, then cement production in this way could potentially cut out most of its CO₂ emissions. The first phase of trial melts by C2Z will be conducted by the Materials Processing Institute using a 250kg induction furnace and this will be scaled up to 6t in an electric arc furnace (EAF). Later, industrial scale melts will be tested in Celsa Steel's EAF in Cardiff, Wales.

CEC is taking a similar approach to HeidelbergCement with its research into using recycled concrete paste. However, HeidelbergCement says it is using the paste to help capture CO₂ in an enforced carbonation step it is testing at cement plants. It too though wants to create a secondary cementitious material (SCM) afterwards. There are also links here to construction and demolition waste and electric cement kilns as covered by Global Cement Weekly previously. The latter is different with regards to what CEC is doing because it is recycling concrete waste to produce an SCM (slag) rather than using an electrically powered kiln to make clinker from limestone. Coolbrook, VTT and the like have had to build electric kilns effectively from scratch or adapt technology from elsewhere for their approaches whilst CEC appears to be about to use existing EAFs in its industrial scale pilot.

Figure 1: Projection of how the Cambridge Electric Cement production process could be used at scale in the UK. Source: UK FIRES. Click to view larger version.

CEC’s forecast of how its process could be used at scale in the UK can be seen above in Figure 1. If the majority of the country’s steel scrap was recycled in this fashion each year then 2.4Mt/yr of CEC cement could be produced. This would represent a quarter of the c10Mt of cement sales reported by the MPA in 2021. Assuming the EAFs were powered by renewables then this could reduce the cement sector’s CO₂ emissions significantly. Although it would still leave the industry looking for other decarbonisation routes for the other three-quarters of cement demand.

C2Z and CEC offer a novel spin on cement production by recycling concrete waste, using an electrical heating step and dodging the process emissions associated with normal ordinary Portland cement (OPC) clinker production. If it did progress to a commercial stage then it would see a continued relationship between steel and cement producers. Currently this is mainly centered around iron and steel slag usage as a SCM. One point of interest here would be how much higher levels of steel recycling and a process like CEC being used regularly would affect existing slag usage as an SCM. It doesn’t look like CEC could solve the cement sector’s CO₂ emission problem all on its own but it could certainly make a difference if it progressed to a commercial stage. As ever with cement sector decarbonisation there appear to be a range of options available to producers.

UK: Cambridge Electric Cement (CEC) has launched the two-year trial of its Cement 2 Zero project, aimed at scaling up production of its net zero-CO₂, demolition waste-based alternative cement. It aims to produce 20t of the material for use in a low-impact construction project. CEC’s method, developed at the University of Cambridge, is based on the conversion of demolition waste into a slag-forming material within a steel furnace.

Developer Julian Allwood said “By combining steel and cement recycling in a single process powered by renewable electricity, we could supplement the global supply of the basic construction materials to support the infrastructure of a zero emissions world and to enable economic development where it is most needed.”

Finland: Geoprime producer Betolar has named Riku Kytömäki as its new president and CEO. Riku's professional background is in materials technology, having served as president and CEO of Exel Composites and held senior positions in Switzerland-based ABB. Kytömäki holds board positions in several international companies and organisations, including polymers producer Teknikum Group. He has management experience in Asian markets where Betolar has expanded during the past few years.

Betolar said "Riku will lead Betolar through its next growth phase as its Geoprime solution is entering active production. Geoprime is a next-generation, low-carbon solution and sustainable alternative to cement: it delivers 80% fewer emissions and 100% cement-free building materials with the same performance as traditional concrete."

Austria: Rail logistics company ÖBB Rail Cargo Group (RCG) says that its haulage of 80,000t/yr of granulated blast furnace slag (GBFS) and clinker to and from w&p Zement's Wietersdorf cement plant in Carinthia by rail has removed 3200 trucks/yr from the road since its start in 2019. RCG's trains deliver the plant's clinker to the Peggau-Deutschfeistritz railway station in Styria, and return to the plant laden with GBFS from steel producer Voestalpine's nearby Leoben refinery.

RCG said that w&p Zement is currently working to increase its operations' reliance on rail, adding "Further innovative transport solutions are already being worked on."

US: Bulk material handling equipment supplier MDG America says that it delivered four chain bucket elevators for Drake Cement's upgrade of its Paulden cement plant in Arizona. Drake Cement installed a new vertical mill grinding plant for cement, granulated blast furnace slag (GBFS) and raw materials grinding at the 0.7Mt/yr integrated plant. The supplier says that two of the elevators will work in a pair, conveying material from a feeder belt, while a third will convey it to the new mill. The fourth elevator will then collect the material for further grinding and metal discharge.

Drake cement secured approval to mine pozzolan for use in the Paulden's plants cement production at Bill Williams Mountain earlier in October 2022. As part of minimising the future mine's impacts, Drake Cement has offered to help the US Forestry Service to thin local woodland as part of local anti-fire management efforts.

Italy: Buzzi Unicem has obtained technical evaluation certification for CEM II/C-M Portland composite cement products to be manufactured at its Trino, Vernasca, Settimello, Guidonia, Barletta and Augusta plants. The new cements will be part of its C-Green product line and the sustainability objectives from its 2030 roadmap. The new products will reduce their clinker factor by using granulated blast furnace slag, fly ash, pozzolan and limestone. They potentially offer up to a 40% reduction in CO₂ emissions per tonne compared to CEM I equivalents. They will be available in 32.5 N/R and 42.5 N/R strength classes for a range of applications. The cement producer hopes that the new products will quickly establish themselves in the market and even becoming the “standard cement” in Italy by 2030.

Bangladesh: The high rate of the US Dollar against the Bangladeshi Taka is forcing local cement producers to raise their prices despite an increase in imports of volumes of raw materials. The country imported 5.12Mt of clinker, granulated slag, limestone, gypsum and fly ash in July and August 2022, a rise of 34% year-on-year, according to the Daily Star newspaper. Golam Kibria, the general manager of Premier Cement, said that the negative currency exchange effect was the main cause of local price rises for cement since the cost of raw materials on international markets had remained stable in recent months.

The country imported 36.1Mt/yr of raw materials for cement production in the 2021 – 2022 financial year. These materials mostly came from Thailand, Vietnam and China through ports in Chattogram and Mongla. This compares to imports of 16.8Mt in the 2017 – 2018 financial year.

US: Royal White Cement has leased a site on the Houston Ship Channel in Houston, Texas. Local press has reported that the company plans to build its second cement terminal in the city there. Houston Peninsula Terminals will operate unloading systems for the storage of cement across three facilities at the site. It is also equipped with multiple railway tracks and heavy truck loading facilities. Royal White Cement owner Marcel Fadi said that the move would help the producer to expand its footprint in Houston and beyond.

Fadi said "We have long operated in the Houston market, but this direct access to storage and bulk unloading along the channel will provide greater efficiencies and flexibility, allowing Royal White Cement to handle and store approximately 100,000t of multiple cementitious products such as slag, grey cement, and white cement."

UK: Bunting plans to promote its magnetic separator and metal detector products at the Powtech trade fair taking place in Germany in late September 2022. The company will be displaying a number of high-strength rare earth magnetic separators including its Plate Magnet Housing (PHMS), Drawer Magnet (HFS), Grate Magnet, Plate Magnet and Bullet Magnet products. Each magnetic separator effectively removes fine tramp iron from a wide range of granules and powders at different locations within a plant. The company promotes its products to the aggregate, quarrying, recycling and slag processing sectors amongst others.

Sri Lanka: Insee Cement has broken ground on its construction of a 45,000m³-capacity storage facility at Hambantota International Port. When commissioned in early 2023, the facility will store ground granulated blast furnace slag (GGBFS) for use in Insee Cement's cement production. Daily News has reported the cost of the facility's construction as US$3m. At 17,300m², the Hambantota storage facility will be the largest warehouse at any port in Sri Lanka.

Insee Cement chair and CEO Nandana Ekanayake said "Hambantota Port is a vital link in our raw materials supply chain. Insee Cement has been using this port since 2018 and so far we have cleared around 1.7Mt of bulk cargo through the port, of which we did a little over 1Mt in 2021. Today, we laid this foundation as another step to strengthen our partnership with Hambantota International Port Group." Ekanayake concluded "We see great potential in developing channels through Hambantota International Port and we will double our investment in the future."