Minerva Engineering’s co-founder Hakan Benzer lifts the lid on the company’s revolutionary Pamir mill, which uses small beads to achieve efficient fine grinding of minerals.
Global Cement (GC): Please could you introduce Minerva Engineering and why you founded it?
Hakan Benzer (HB): Minerva Engineering was founded in Ankara, Türkiye, as a research and development company to develop low-carbon emissions and more environmentally-friendly procedures for heavy industry. Recognising the significant energy consumption and inefficiency of traditional manufacturing methods, we sought to develop solutions that could offer substantial improvements in both energy use and operational efficiency. The company is researching carbon capturing and reducing the clinker factor of cement, as well as developing the Pamir mill (also known as the bead mill), which dramatically improves the efficiency of grinding clinker, slag, fly ash, natural pozzolans and other minerals.
The Pamir mill originated from the recognition of the limitations of conventional grinding and milling technologies. This involved a series of experiments into how the optimum particle size reduction could be achieved more efficiently, specifically how to achieve ultra-fine particle sizes with higher efficiency and lower energy consumption. Representing a solution to this challenge, the Pamir mill represents a significant step forward for grinding technology.
GC: How does the Pamir mill work?
HB: The Pamir mill is a small horizontal mill that contains beads of 2 - 8mm in diameter. These are agitated by a propeller at high speeds, which leads to intense shear forces and impact energy imparted onto the feed material. This results in a rapid and efficient reduction of the particle size.
The mill’s design optimises the distribution of bead sizes and the flow of material through the mill to ensure uniform grinding and low energy consumption. According to the research that we have conducted so far, the energy consumption per tonne is lower than that of traditional methods.
GC: What are the advantages of the Pamir mill?
HB: The advantages of the Pamir mill include its ability to achieve extremely fine particle sizes, which is crucial for cement production, especially low-clinker blends. It also uses less energy per unit of product compared to traditional technologies. This efficiency reduces operational costs and minimises the environmental impact of the grinding process. Additionally, the Pamir mill is versatile and capable of processing a wide range of materials, including those that are conventionally ‘difficult to grind.’
In dry grinding applications such as high-performance cement, calcined clay, fly ash and slag, the Pamir mill improves product quality and capacity while lowering energy consumption and increasing profitability. The mechanical activation capability of the Pamir mill also allows users to work on sustainable solutions for the cement industry. As a result of its low CO2 footprint, the Pamir mill will result in lower CO2 emissions from cement plants.
| Diameter (m) | Length (m) | Power (kW) | Volume (m3) | Power intensity (kW/m3) | |
| Ball mill | 4.2 | 13 | 2600 | 180 | 14.4 |
| Pamir mill | 1.3 | 3 | 900 | 3 | 300 |
Above - Table 1
GC: Why is the Pamir mill so efficient?
HB: Table 1 shows that the power intensity for a moderate-size ball mill is 14.4kW/m3. A considerably smaller Pamir mill has a power intensity of 300kW/m3, 20 times as much power per cubic metre. This is where the success comes from. In a ball mill, you can only use 32% of the total volume - 68% is empty. However, in the Pamir mill, we can fill up to 85%, so we have far fewer voids. Also, ‘the tip’ speed in the ball mill is 2.5 - 3.5m/s. With the Pamir mill the tip speed can be increased to 5 - 8m/s. This results in far greater kinetic energy being imparted to the feed material than with a ball mill.
GC: How do the beads not ‘grind themselves’? What is their average life-span?
HB: The design of the mill ensures that the beads are kept in constant motion, reducing the likelihood of them colliding with each other in a way that would cause significant wear. As a result, the beads have a long life-span, typically lasting for many cycles of the milling process before needing replacement. This is comparable to the balls in a ball mill. The exact life-span varies depending on the material being processed and the operating conditions of the mill.
GC: What are the disadvantages to using the bead mill compared to a conventional one?
HB: One of the concerns is the material preparation requirement with this advanced technology. At its current form we prefer to feed max feed size of 0.5mm. Additionally, the moisture content of the feed material should be below 1.5%. There are also challenges with the transport of material within the mill. As a result, we must optimise the types of grinding aids and their dosages, which can be higher than in a typical ball mill.
GC: What stage has development reached?
HB: The Pamir mill is operational at Bursa Çimento and Adana Oyak Çimento, both in Türkiye and both grinding cement clinker. The 1m3 Bursa mill has been running at 50t/hr for five years, during which time we have observed the agreeable wear behaviour characteristics described above. At Adana, which is using the mill for white cement clinker, we have not observed notable wear and have not replaced anything to date.The long-term energy-saving compared to a ball mill is 16% at Bursa, with a 22% increase in grey cement production. There has been a 10% reduction in energy use at Adana, with a 25% capacity in white cement production.
GC: What is the next stage for this technology?
HB: We know that the Pamir mill will be vital to cement plants in the future, and we are testing various adaptations right now. This includes systems that incorporate a roller press alongside the Pamir mill, as well as those that combine a vertical roller mill and Pamir mill. We have positive results compared to conventional combinations that rely on ball mills so far.
We are also focused on separate grinding for clinker, pozzolans, fly ash, etc. We can grind these separately and combine them in a mixer. This will allow mix designers to easily adjust the exact size distribution of each component and also the exact granulometry for the final cement product, in order to optimise their desired properties.
Beyond this, we are scaling up capacity and expanding the applications that the Pamir mill is used within across different industries. We aim to further optimise the mill’s design to improve its efficiency, versatility and ease of use. Additionally, we plan to engage with more partners for additional real-world testing and to start integrating feedback from a broader range of applications. This will help us refine the technology further and prepare it for wider commercial adoption.
GC: What impact do you hope it will have in the next 5 - 10 years?
HB: Over the next 5 - 10 years, we hope that the Pamir mill will have a significant impact on the materials processing industry by making it more sustainable and efficient. Our goal is for the mill to become a standard solution for achieving fine particle sizes for a range of materials, reducing the energy and waste associated with traditional milling processes. We intend to offer new special solutions in the near future by transferring the innovative ideas that we are working on in our research and development centre laboratory into industrial applications.
We will continue to strive toward goals such as changing existing sector technologies into wholly new ones, lowering energy usage, expanding capacity, and improving product quality. By improving process efficiency and reducing operational costs, we believe the bead mill will play a crucial role in driving innovation and sustainability in materials processing across various sectors.
GC: Thank you for your time today Mr Benzer.
HB: You are very welcome.
