Our proven process technology. Your high-quality cristobalite.

Cristobalite plants

Tailor-made process technology is needed to produce high-quality cristobalite. Since raw sand qualities differ, individual fine-tuning is required – both in the selection of the appropriate additive addition and in the thermal treatment. To achieve top quality, we at Grenzebach always think ahead on your behalf and go into detail when designing your production plant. To ensure that you benefit from high product qualities, we use our many years of process experience to provide targeted recrystallization of your quartz sand.

From planning and commissioning to maintenance work on existing plants, we are at your side as a full-service partner. Our expertise is characterized by our 120 years of experience in mechanical and thermal process engineering, thanks to Babcock BSH.

Grenzebach: Full-Service Supplier


From Germany to the world – Grenzebach has been planning, supplying and installing cristobalite plants for decades. Our holistic view of your project is what sets us apart as a partner. That’s why we analyze your raw sand qualities at our technical center right at the start of the project. Your quality requirements and wishes are reflected in the design of your cristobalite plant. A high whiteness index and a low yellowness index are decisive factors for us. We pay attention to the longevity and energy efficiency of our plants and solutions for our customers. You will receive a plant concept that is individually tailored to your needs – including full-service support throughout your cristobalite plant’s entire product life cycle.

The advantage for you: You benefit from a supplier that provides you with a complete system, tailored to your quality requirements and throughput rates, and that always thinks one step ahead. Around the clock. Around the world.

Our services

  • Analyses and feasibility studies
  • Plant engineering and customized dimensioning
  • Supply of all necessary plant components, from hardware to software
  • Worldwide installation and commissioning by Grenzebach experts on site
  • Regular training and education for employees
  • After-sales support throughout the entire product life cycle

Calcination of quartz to cristobalite

The manufacturing process

For the production of cristobalite, quartz is first washed, classified and screened. The heart of the cristobalite plant then comprises a sophisticated system of various thermal apparatuses. In the first step, additives are mixed with the quartz sand. After upstream drying and preheating of the quartz, the essential recrystallization (calcination) of the quartz into cristobalite takes place. In downstream cooling processes, the cristobalite’s temperature is brought down to a manageable level.

Our individual process technologies for a cristobalite plant

Process steps for the production of Cristobalit

Raw material silo

The raw material is washed, classified and screened.


The untreated silica sand is conveyed to the feeding device in front of the drum dryer.

Metering unit

The silica sand is mixed with chemical additives. This step affects the quality of the cristobalite produced.

Drum dryer

The preconditioned silica sand is completely dried and preheated.

Rotary kiln

The calcination of quartz to cristobalite in the high-temperature zone of the rotary kiln represents a decisive process step. Here, targeted temperature control is required to ensure accurate recrystallization as cristobalite.

Grenzebach’s rotary kiln is characterized by a simple, robust design, high operational reliability and high throughput rates.

Fluidized bed cooler

The temperature of the cristobalite produced is brought down to a manageable level in the downstream two-stage cooling process. In the fluidized bed cooler, the cristobalite is air-cooled in a first step.

Shaft heat exchanger

In the shaft heat exchanger, a cooler that works indirectly with water, the cristobalite is then finally brought to a manageable final temperature.

Black spot detection

An inline measuring facility inspects the finished cristobalite for black spots. To achieve consistent product quality and avoid black spots during the production process, an intelligent control system guides the manufacturing process.

Grenzebach enables the subsequent installation of the inline measuring option and intelligent process control.

Heat recovery Cristobalit production

Cristobalite plant: Smart heat recovery

Energy Efficiency

The production of cristobalite is associated with high energy consumption. Grenzebach therefore ensures energy efficiency in its process solutions, so that your energy costs can be cut and resource consumption can be sustainably reduced.

The waste heat from the cooling air used in the fluidized bed cooler is recovered using state-of-the-art technology and supports the heating of the rotary kiln process. The rotary kiln therefore requires less external energy to achieve the desired temperature for the calcination process.

Flue gas from the rotary kiln process is also used to dry and heat the silica sand in the drum dryer. Unused heat energy thus becomes usable, conserving resources and increasing the energy efficiency of the overall plant. You can improve your climate protection balance sheet and sustainably reduce CO2 emissions.

Analyses of recrystallization of quartz into cristobalite

Early raw material analyses are essential for high-quality cristobalite

For the targeted production of cristobalite, we examine your starting material at our own laboratory and technical center in Bad Hersfeld. The examinations and measurements that take place there form the cornerstone of your future production plant and provide information about the expected quality of your end product.


We use state-of-the-art test equipment to analyze the recrystallization of quartz into cristobalite. On a small scale, we can also check reaction behavior with different additives. These analyses enable us to identify the achievable whiteness and yellowness indices and provide advance information on the expected quality of your cristobalite.


Based on these findings, we optimize the manufacturing process and ensure targeted preparation of your quartz sand.


High efficiency cristobalit production in Vietnam

Our passion for cristobalite: High efficiency in Vietnam

Case Study

Our Vietnamese customer no longer wanted to pay high prices for the valuable raw material cristobalite it needs for its product manufacturing. The company therefore decided to produce its own cristobalite.

In 22 months, Grenzebach’s process technology experts from Bad Hersfeld installed an operational plant to produce 80,000 metric tons of cristobalite a year at the customer’s site in Vietnam.

Applications of cristobalite

White. Rugged. Versatile.

Cristobalite’s exceptionally high whiteness, high chemical resistance and low density make it an ideal filler and pigment for various specialty products.

Depending on the particle size, cristobalite can be found in various products. As a fine or ultra-fine powder, it is used in colorants, while as a coarse powder or grain, it is found in wall plaster. Due to its color saturation and luminosity, cristobalite is particularly popular as an additive in engineered stone and dental ceramics.


Engineered Stone: Luminous. Durable. Scratch-resistant.

Engineered stone is a composite material made of cristobalite and resin. Pressed into slabs or larger blocks, it is often used to make kitchen countertops, flooring and interior walls. The granite imitation has high resistance to stains and scratches, as well as radiant luminosity and a wide color spectrum.

Dental ceramics: Precise. Fireproof. Stable.

The quality of the investment material and the optimized interplay of cold and heat are decisive for accurately fitting dental ceramics. Since the beginning of the 20th century, cristobalite has been used in dental technology as a refractory investment material in which dental castings are modeled. Cristobalite filler is characterized by its precision, refractoriness and stability.

Full-Service Support

Construction and commissioning of a new cristobalite plant are only the first steps in a positive, long-lasting customer relationship. Professional service in day-to-day operations is just as important: we want your investment to be consistently and holistically profitable. That’s why our engineers are there to support you throughout the entire life cycle of your cristobalite plant. Around the world. Around the clock. Regular plant upgrades are just as integral a part of our philosophy as continuous training and education for your employees – virtually or on-site.


Your contact person: Matthias Brandau

Are you planning a new cristobalite plant or would you like to learn more about our process technology? Call or write us with your requirements. We look forward to hearing from you.

Matthias Brandau Grenzebach