Internship at the World's Largest Cement Plant of HeidelbergCement

Field report by Simon K., Intern at HeidelbergCement

My name is Simon K. and I study mechanical engineering at RWTH Aachen. When I reached my 5th semester, it was time to complete a 3-month internship in the field. I extended this by a further 3 months, and so had the amazing opportunity to spend 6 months working at one of the world's largest cement plants in Indonesia.

HeidelbergCement is one of Germany's largest companies. It is the second-largest cement manufacturer globally, and the world market leader in aggregates. The company thus offers very good career perspectives. I also have a personal interest in process technologies, and large industrial plants have always been a fascination of mine. So, I decided to write and ask about the possibility for an international internship. In discussions with the Human Resources department, we determined where I would be stationed. From the very beginning, Asia was my region of choice, so it was soon decided that I would go to Indonesia for an internship at Indocement. Other options were Africa, Eastern Europe, and North America. In order to receive a first glimpse of the cement manufacturing process, I began with a three-week internship at the Leimen cement plant near Heidelberg. After that, it was not long before I made the journey to one of the largest cement plants in the world, at Citeureup.


The plant is located roughly 20 km south of Indonesia's capital of Jakarta. There, ten production lines are in operation. In addition to the production lines and two quarries, the plant also houses a power plant, a sack factory, a water treatment facility, and the local offices of HeidelbergCement Technology Center (HTC). This means that an unbelievable number of professional disciplines are brought together at the site. Sales staff work at Citeureup alongside scientists (e.g. biologists and geologists) and engineers from various fields. The main focus of my project was on optimisation of an air separator at the raw mill. An air separator is used to isolate different fraction sizes in the ground material. Fine fractions are separated out as an individual product, while larger-sized fractions are returned to the mill – making this machine key for the efficiency of the grinding process.

Over the course of my internship, I also had opportunities to work on other, smaller projects in different parts of the plant. These involved measures to optimise machines at the site that had been the source of persistent problems. In every case, it was necessary to understand the machines and their functions, in order to draw conclusions about the actual problem. The knowledge I had gained up to that point in my studies proved very valuable. For all the projects, I received support from the Indonesian engineers and HTC staff. We met regularly to review the progress of my projects. Naturally, there was also ample support provided outside of these meetings as well.

Another important aim of an international internship is, of course, getting to know a different culture. This is part of what made Asia so attractive to me from the start. In Indonesia, things were so different to anything I knew in Germany: the traffic, the food, the organisation of the company, the way of working, and my own standard of living. The way of working is much different than what one finds in Germany. Meetings, for instance, are held more frequently. The workers are poorly trained, and often have only simple tools available. They also need more instruction than I was used to. My standard of living was buoyed by the generous stipend I received, including a personal driver and well-furnished apartment in a vibrant neighbourhood in southern Jakarta.

Anyone who lives in Jakarta has to get used to long travel times. For the 20 km to the plant, one to two hours were not unusual. As for traffic rules, they are initially a complete riddle for any European, and public transport is nearly non-existent. So, I had to learn to make optimum use of the time spent in the car.

It was difficult to forge close contacts with the native Indonesians, which meant that most of my free time was spent with other expats living in Jakarta. One reason could be the hierarchal mindset of people. Another is certainly the huge difference in cultures.


The biggest challenge for me was getting used to Indonesia's culture and way of working. What I really enjoyed was putting into practice the things I had learned in my studies. The broad range of different projects also made my work very interesting. I learned a lot about construction and machinery, as well as electrical engineering and process technology. In addition to working at the plant, I also had the opportunity to explore the country. Indonesia is full of things to do and see. There are numerous ancient temples, gorgeous beaches, outstanding diving opportunities, and grandiose volcanic landscapes – and Jakarta is known for its nightlife.

The internship met and surpassed all of my expectations. I learned an amazing amount and gained genuine insight into the processes of cement manufacturing. At the same time, I got to know Indonesia, and immersed myself in a different culture. In all, I would say that my time there was one of immense personal growth.

Simon K.: Intern at HeidelbergCement. Simon K.: Bachelor student in Mechanical Engineering at RWTH Aachen and Intern at HeidelbergCement; view of the cyclone preheater on line P11 at the Citeureup cement plant
Simon K.: Internship at the world's largest cement plant of HeidelbergCement

Students (tile motive).