Celitement GmbH was formed in 2009 but it is still not possible to buy the new binding agent. Why is this?

It is not unusual for the development of a completely new type of binding agent, including the requisite production process, to need periods of up to 15 years from the basic research to market readiness and industrialization of the production process. The development process for such projects can be described by, among other things, TRLs = Technical Readiness Levels.
In addition to the above-mentioned product and process engineering development and scale-up work from the idea (TRL=1) via the initial laboratory synthesis to cost-effective operation of the first industrial reference plant (TRL=9) it is also necessary to deal with a range of official or administrative issues for the products, such as registration under the laws governing chemicals, or construction authority issues.
Safe application of new binding agents also requires a stepwise approach on the part of our innovators and their customers – from the first laboratory test to use on an industrial scale with secured legal approval and economic viability.
Commercially available quantities of Celitement always imply an industrial production plant. Any investment decision in what we will call the first industrial reference plant, to differentiate it from the existing pilot plant, will be based on three cornerstones:

1.1 A dependable mechanical and plant design concept backed by the plant constructors and manufacturers of the requisite process technology. This can only be accomplished when the entire mechanical, process and control technology as well as the storage and utilities infrastructure for an industrial plant have been specified. The appropriate systems for production and quality assurance must also be fully defined.
1.2 Before new substances (such as hCHS phases) can be placed on the market in Europe they must fulfil all the legal chemical preconditions (so-called REACH registration).
1.3 The product must be marketable from the technical and price aspects and the customers must be able to use it in fairly large quantities immediately after the first industrial plant comes into operation.

Fulfilling all three requirements for the development of a completely new binding agent system is a tedious and expensive process. In many areas we are breaking completely new ground, which means that we are faced with a great deal of hard work. Perseverance and patience is needed for such new developments, especially in the building materials sector. Firstly, relatively large capital investment in machinery and plant is always needed to provide enough sample material for realistic testing of building materials. It was only when our pilot plant was commissioned at the end of 2011 that it was possible to continue the development of production processes, which had previously only been tested on a laboratory scale, until they are ready for industrial use. The technologically most complex and demanding process step is the mechanochemical (“tribochemical”) activation grinding. Choosing the optimum grinding technology for this purpose required very extensive and time-consuming preliminary trials with a wide variety of grinding systems. It was therefore only in 2013 that a vibrating tube mill was installed in the pilot plant. This was chosen because it allows the energy input and the stressing period as well as the type of stressing to be varied very flexibly. After the commissioning it was also possible for the first time to produce test materials in fairly large quantities (approx. 100 kg per day) and carry out realistic tests on the product properties. From mid 2021 Celitement GmbH will have a substantially larger and more efficient grinding system available in its pilot plant that operates on a different grinding principle. The system that is then installed can be scaled up to an industrial level. This means that the most important component in the Celitement production process has been conclusively defined. The dimensioning and design engineering of a complete industrial plant to the stage where it is ready for placement of an order are well advanced but not yet finally complete.
What also costs a great deal of time (and money) are the legal approval issues involved in the development of new substances. This is often not public knowledge. In order to market a new substance in Europe it is first necessary to obtain approval under the laws governing chemicals in accordance with the REACH regulation from the appropriate European authorities (ECHA). Substances that are later to be placed on the European Market in the quantity range > 1,000 t require the compilation of a substance safety dossier with extensive and complex tests. These should therefore only be carried out when the final composition and properties of new substance have already been securely defined. We reached this point in mid 2014. During the course of 2014 we then started the very complex tests required by the law governing chemicals. The REACH registration was successfully completed in 2018 after almost four years. Up to this point Celitement GmbH was only allowed to pass on test material to selected innovators for research purposes within the framework of a PPORD (Product and Process Oriented Research and Development) approval. Quite apart from the fact that the quantities from the pilot plant were too small, no commercial marketing would have been permitted under the laws governing chemicals. Only with the successful conclusion of the REACH registration have we been working increasingly with innovators to optimize Celitement to ultimate market maturity. We have made great progress in many laboratory and field trials. However, further practical trials with more test material (up to 5 tonnes per trial) are needed so that our associate, Schwenk Zement KG from Ulm, can decide about investment in an industrial plant. These quantities will only be available after the extension of the pilot plant in Karlsruhe, which has already begun. Only after conclusive trials with substantially larger test quantities will it be possible to make a reliable assessment of whether the market will accept Celitement as a new binding agent concept to such an extent that investment in an industrial reference plant is economically justified.

The principle of Celitement seems to be really simple so why hasn’t this idea come up before?

One is always smarter with hindsight. However, the Celitement project is a great example of how a marketable product can emerge from an idea from basic research. The researchers at the Karlsruhe Institute of Technology (KIT) had originally been concerned with the hydration mechanism of the most important mineral phase in Portland cement clinker, i.e. tricalcium silicate (Ca3OSiO4 or empirical formula Ca3SiO5, abbreviated to C3S). They established that a previously unknown intermediate phase occurs briefly along the route to the end product of the hydration of this water-free calcium silicate phase, the so-called C-S-H, i.e. Calcium Silicate Hydrate (the “glue” in mortar and concrete). The idea was then simply to produce this intermediate phase and use it as a “semi-finished” binding agent. Just to find this reactive intermediate phase of cement hydration that actually only appears very briefly in aqueous solution and to carry out accurate analytical characterization requires special knowledge and analytical techniques that even the largest cement producers do not have in their laboratories. There are major research establishments for this purpose, such as the Helmholz Association, to which the KIT also belongs. As cement producers we have not been asleep and were not too “dense” to discover the principle of Celitement ourselves. We simply did not possess the working groups with their strongly interdisciplinary links and the requisite large-scale analysis systems with their very expensive and specialized machinery and equipment. And then, as every researcher will acknowledge, you certainly also need a bit of luck to be successful.

What is the current state of development and the technical maturity of Celitement? Is the development of the project scientifically sound?

This question can be answered by the Technical Readiness Level – for the overall process we are at TRL 7. One advantage of the Celitement process is that the two main process stages, namely autoclaving and activation grinding, are known in principle from familiar and established production processes for building materials. Autoclaving under saturated steam conditions is familiar from the production of aerated concrete and sandlime bricks. Dry activation grinding can be carried out with grinding plants that are familiar from ultrafine grinding. However, the way these two production stages are combined and the intermediate and end products that are generated are completely new. Over the entire development period so far we have already produced Celitements in the high two-figure tonne range. This means that we know the fundamental product properties really well. However, through the work with our innovators we have undertaken many changes in the detail. We are now certain that we can produce material with properties that correspond to the future quality levels from an industrial plant.

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