Anant Pokharna, CEO, Unisol Inc, reveals the cutting-edge innovations in grinding aids that are revolutionising cement production.
Unisol’s mission emphasises innovation and R&D. Can you share recent advancements or innovations in grinding aids that Unisol has developed?
Depleting limestone deposits in India (and globally) are forcing cement producers to use marginal grade limestones, in turn, depending on ‘sweeteners’ or high-grade limestones for achieving the right quality.
Unisol has developed a range of chemical additives (formulations), which when added at the cement grinding mill inlet in dosages ranging from 0.05 per cent to 0.15 per cent, help cement producers significantly reduce / eliminate their sweetener consumption. Reduced sweetener consumption translates into reduced cost of cement manufacturing, enhanced life of limestone deposits, lower carbon footprint in cement manufacturing, and enhanced efficiency in general.
These chemical additives work on the principle of delivering significantly improved compressive strengths of cement mortars, in turn allowing for reduced need of sweeteners in raw mix.
How do Unisol’s grinding aids specifically help in reducing the energy required for particle size reduction in grinding mills?
Our grinding aids reduce agglomeration in cement mills by enhancing electrostatic repulsion and reducing Van der Waals forces between the broken particles in cement mills. The resultant deagglomeration leads to reduction in energy requirement for achieving desired surface area of final cement. Thus, the same power consumption allows for higher mill output by anywhere between 5 per cent to 15 per cent over the baseline levels. This also leads to a reduction in specific power consumption by 2-3 KWh/tonne of cement.
Explain the impact of Unisol’s products on the overall grindability and flow of cement.
There is a significant free charge that gets built up on the clinker surface inside the cement mills as the particle size continues to go down. The particles reduce their free charge by agglomerating together, in turn increasing the energy requirements for achieving desired surface area of the final cement. Our grinding aids work on the principle of enhancing electrostatic repulsion and reducing Van der Waals forces as explained in the above query too. This leads to reduction in energy considerations and significantly increased grindability inside the cement mill.
Not all grinding aids have a significant impact on powder fluidity of the resultant cement. We design certain formulations, which enhance the cement fluidity substantially, when the customer specifically asks for this property.
What are the primary benefits of using your grinding aids in terms of mill productivity and the quality of the final product?
a. Increased mill throughput by 5-15 per cent
b. Reduced specific power consumption in cement grinding mills by 2-3 KWh/tonne.
c. Enhanced compressive strength at early ages (1D and 3D) by up to 4 mpa and/or later ages (7D and 28D) by up to 10 mpa.
d. Reduced clinker factor by up to 10 per cent while maintaining the same cement quality, leading to significant reduction in cost and carbon footprint of cement production. Clinker is typically replaced with supplementary cementitious materials (SCM) such as fly ash, slag and pond ash, which are lower cost and have a significantly lower carbon footprint.
e. Modified setting times based on the
plant’s requirement.
f. Reduced water demand in resultant concrete and improved slump retention.
Unisol’s value propositions include increasing mill throughput and reducing power consumption. Can you elaborate on how your products achieve these outcomes?
When the primary objective is to reduce specific power consumption or to increase throughput of cement grinding mills, we look to deliver products whose mode of impact is two-pronged.
First, these products look to reduce or break down Van der Waals forces and enhance electrostatic repulsion between broken particles in the cement mills. This leads to deagglomeration, which allows for higher mill throughput with same specific power or lower specific power consumption per ton of cement.
Second, these grinding aids get adsorbed to the cement particles and reduce the surface charges on the broken particles in the mill. This again leads to lower agglomeration and hence, reduced specific power consumption.
How do your quality improvers and strength enhancers contribute to increasing compressive strength and reducing the clinker factor in cement?
Our strength enhancing grinding aids get adsorbed to the surface of cement particles. They have a beneficial impact on the rheology of the resultant mortar or concrete, leading to accelerated hydration of certain phases of cement, such as C3S and/or C3A. Cement producers witness accelerated strength growth by 2-10 mpa across all ages, improved setting times and other relevant properties when they add our strength enhancing grinding aids to cement
mill inlet.
Most cement producers tend to reduce their clinker factor in cement by ~4-5 per cent, and increase corresponding quantities of SCM such as fly ash and slag, while maintaining their cement quality by deploying our strength enhancing grinding aids. We have been able to help cement producers reduce their clinker content by up to 10 per cent in certain cases.
Can you provide examples or case studies where Unisol’s grinding aids have significantly improved cement plant performance, particularly in terms of energy efficiency and product quality?
A large cement producer was looking to deploy a grinding aid for the purpose of both increased mill output and improved cement quality, at one of its cement plants in Southern India. More specifically, this client wanted to offset the treatment cost of grinding aid completely by reduction in specific power consumption; thereby making the grinding aid cost-neutral. The add-on improvement in cement quality due to accelerated cement hydration, therefore, would effectively be achieved without any cost to the plant.
Unisol delivered a grinding aid to the plant in concentrated form and leveraged on-site blending, with water sourced locally at the plant, to ensure that the treatment cost was kept at the lowest possible. Plant witnessed a reduction in specific power consumption by around 2.5 KWh/tonne of cement, which was sufficient to offset the entire treatment cost of the grinding aid as the power cost was relatively high for that specific plant.
In addition, usage of our grinding aid increased the cement strength by 2-3 MPa across all ages of cement. In effect, the plant was able to deliver improved cement quality to its customers without any net increase in its variable cost of production.
Looking ahead, what trends or advancements do you foresee in the field of grinding aids, and how is Unisol positioning itself to lead in this area?
We foresee the following three trends developing in the domain of grinding aids and performance enhancers used by cement manufacturers.
Firstly, with the depleting limestone deposits and the general pressure on the cement industry to reduce its carbon footprint, there would be an enhanced demand for deployment of high impact quality improvers to drive and promote marginal grade limestones in cement production. Plants will look to reduce and eliminate their sweetener consumption by leveraging cutting-edge chemical additives.
Secondly, all stakeholders in the cement manufacturing ecosystem including cement producers, regulatory bodies, suppliers, and consumers will have to come together to promote cements with much lower clinker factor. Clinker factors will pushed downwards globally and grinding aids and relevant chemical additives will play a significant role in this evolving landscape. New-age quality improvers will replace conventional grinding aids in helping cement producers achieve the desired cement performance with much lower clinker factor.
Thirdly, grinding aid suppliers will have to improve their offerings, deliver high impact products, and still ensure cost effectiveness of their products. More customisations and innovations such as on-site blending will become the norm in the grinding aid industry going forward.
At Unisol, we have been pioneering the concepts such as bespoke formulations and on-site blending over the last few years. These concepts allow us to deliver some of the highest impact chemical formulations to our customers, while ensuring lean, flexible and eco-friendly delivery models. Further, we have been strengthening our research capabilities by bringing more PhDs in the team and keeping our focus razor sharp on developing advanced formulations for emerging needs of the industry.
– Kanika Mathur
