The cement industry is worldwide one of the main contributors to man-made CO2 emissions, estimated at 7% of global emissions. To keep pace with the demand and pressure to reduce CO2 emissions, a shift to sustainable building materials for housing and infrastructure must still be continued. Cement manufacturers can make significant progress toward sustainability goals with alternative fuels and efficiency projects by reducing clinker content through cementitious additives (SCM).

1. RESHAPE YOUR
CO2
FOOTPRINT
C/CLAY is part of LOESCHE’s

2. 02 | 03 Facing the challenge
FACING THE CHALLENGE
CEMENT IN GENERAL
The cement industry is worldwide one of the
main contributors to man-made CO2
emissions, estimated at 7% of global
emissions. To keep pace with the demand
and pressure to reduce CO2
emissions, a shift
to sustainable building materials for housing
and infrastructure must still be continued.
Cement manufacturers can make significant
progress toward sustainability goals with
alternative fuels and efficiency projects by
reducing clinker content through cementitious
additives (SCM).
1. Consumption:
The cement consumption is high and will continue to
stay at 4 – 5 bn tons per year due to
• population growth
• urbanisation
• demand for technical infrastructure, housing and
buildings for climate change adaptions
2. CO2
emissions:
• cement industry produces around 800 kg CO2
per ton OPC corresponding to ~ 10% of
anthropogenic CO2
.
• CO2
pricing increasing as a cost factor due to
worldwide CO2
pricing initiatives
• cement producers in a strong position to lower
CO2
emissions.
3. Availability:
• regionally varying limestone availability for
clinker production
• expensive imports
• no sustainable extenders available
• decreasing amount of SCMs, e.g. fly ash, even
in developed countries
SUSTAINABILITY INITIATIVES ARE MAINLY DRIVEN BY THREE INFLUENCING FACTORS:

3. LOESCHE is your reliable partner for projects
ranging from vertical roller mills to complete
grinding plants and sustainable technologies to
reduce your plant’s emissions.
Substituting clinker with calcined clay presents an
array of benefits through the supply chain. Our
clients switch to C/CLAY technology due to at
least one of the following reasons:
1. a drive towards a more sustainable
production with lower CO2
emissions
2. high availability of clay causes lower material
costs when facing shortages in limestone,
clinker or conventional SCM supply
3. cost pressures can be mitigated by the
comparative cost advantages of calcined clay
with lower capital investment and reduced
operation and maintenance costs (compared
to clinker production)
YOUR BENEFITS
C/Clay offers a large step towards sustainable
cement production and cost savings.
ADDITIONAL BENEFITS
• compatibility with many GREENKEY Solutions by LOESCHE
• saving grinding energy and mixing / homogenization equipment due to
co-grinding in LOESCHE mills
LOESCHE attaches great importance to ensuring that the cement properties meet the high
requirements of our customers. For this purpose, many boundary parameters are evaluated
and included in the optimum process technology.

4. 04 | 05
INTRODUCING
CALCINED CLAY
THE WAY OF CLAY PROCESSING
Introducing calcined clay
Up to 60 % of all CO2
emissions in the cement pro-
duction are caused by the clinker specific reaction
during calcination. Calcined clay is a cost-effective,
sustainable alternative with significant SCM poten-
tial, replacing up to 50% clinker. In addition, when
calcining clay, less fuel is required. This leads to a
further emission reduction of ~ 10 %. The replace-
ment of clinker in the cement production through
calcined clay, can therefore reduce emissions by
approximately 40 %.
Our C/CLAY Technology exploits this potential
while maintaining cement’s strength development
and quality standards as well as cement color.
Additionally, C/CLAY enables operators to save
costs due to lower fuel consumption, grinding and
maintenance cost as well as CAPEX investments.
1. QUARRYING 2. PRETREATMENT
8. APPLICATION 7. PACKAGING
• detecting a suitable clay deposit
• analysis via geological service
Basic requirement:
clay content > 40 %, even lower
contents are possible due to clay
enrichment in LOESCHE mills
• special equipment for wet clay
• preparation for rotary kiln:
particles up to several centimeters
•
preparation for flash calcination:
particles < 2 mm
Package types:
• bulk material
• cement packages
• truck load
Destinations:
• shipping to grinding terminal, cement
manufacturer or ready-mix station
• suitable for all common concrete
types
• improvement of the cement
workability and reactivity
possible with adequate grinding
in LOESCHE mills

5. 3. CALCINATION* 4. COOLING
6. BLENDING 5. GRINDING
Three solutions:
• refurbished rotary kiln: re-use an
existing rotary kiln
• flash calciner
• new rotary kiln
• rotary cooler
• modified grate cooler
• cyclone cooler
• two possible ways:
- co-grinding
- separate grinding
• drying and grinding in one step
• batch grinding: fast change of
feed material possible
Only LOESCHE mills
separate quartz
during grinding.
• all types of cement possible
• suits perfect to LC3 cements*
• no blending with co-grinding
* see https://www.lc3.ch
• has a layered structure
• has absorption capabilities
• is non-reactive
Raw clay
• consists of thermally decomposed
clay minerals
• contains amorphous alumosilicates
• is puzzolanically reactive
Meta-clay
20°C
H2
O
(clinker 1.450°C)
600-900°
Heating up clay to a certain extent, depending on
• type of clay (kaolin, montmorillonite, illite)
• chemical composition
• granulometry of feed
• used technology (rotary kiln/flash calciner)
This leads to chemical reactions that give the material
puzzolanic reactivity, similar to fly ash or trass.
*CALCINATION PROCEDURE
Image source: https://doi.org/10.25643/bau-
haus-universitaet.4096

6. 06 | 07 Introducing calcined clay
Propertiesinconcretearecomparabletoconventionalpuzzolan
suchasflyashornaturalpuzzolan.
PROPERTIES OF CALCINED CLAY
Strength development of cement:
• depending on the reactivity
• reactivity of calcined clay improvable by effective burning
and grinding (mechanical activation)
• a wide range of clay reactivity i.a. depending on
mineralogical content
Durability of concrete:
• positive effects of calcined clay due to lower capillary porosity
• enhanced chloride resistance of concrete
• suppresses the alkali silica reaction
Workability of calcined clay:
• similar workability compared to conventional cement
achievable with optimal processing
• improvable by sufficient grinding
• no segregation and no bleeding to be expected
Photo Source: IAB Weimar
Above: LOESCHE Test Center

7. LOESCHE SOLUTIONS
C/CLAY technology means you have the choice:
rotary kiln refurbishments, new flash calciners or new rotary kilns.
LOESCHE enables you to select the right technology to calcine clay across
refurbishing your existing rotary kiln and constructing a new flash calciner or rotary
kiln. We bundle the competences in our group, especially through our youngest
member of the worldwide LOESCHE Group: Dynamis.
We evaluate your business goals, analyze the available raw materials and the
relative investment and operating costs. LOESCHE offers state-of-the-art C/CLAY
technology in a comprehensive package.
Dynamis was founded in 2003 as an engineering company in Brazil.
Early on, the company specialized in combustion and industrial
processes. It did not take long for Dynamis to start developing and
supplying its own industrial equipment and become a reference,
especially in the main burner market.
Dynamis focuses on innovation, technology and commitment to its
customers and has grown rapidly over the last fifteen years since
developing the first calcined clay plant at CIPLAN, Brazil.
Thus, the company grew to become an important player with great
future prospects in the sector of combustion equipment. These
prospects have reached a new level following the agreement reached in September 2021, which
integrates Dynamis into the international LOESCHE family.
Dynamis has a qualified team with 40 engineers and designers with global experience in the
cement, mining, metallurgical and paper industry.
WELCOMING DYNAMIS TO THE WORLDWIDE LOESCHE FAMILY

8. 08 | 09 LOESCHE solutions
LOESCHE‘s goal is to guide you from identification to concept and production
of your first calcined clay.
A PATH TO CALCINED CLAY PRODUCTION:
FROM PROJECT EVALUATION TO EXECUTION
LOESCHE has a clear process that guides you from project identification to technology definition to
turnkey engineering of C/CLAY plants. For each project, the technology to be used - either a
refurbished rotary kiln, a flash calciner or a new rotary kiln - must be evaluated. LOESCHE bundles
its know-how and shows you a clear way to successful calcined clay production.
Phase 1
Phase 2
Phase 3
Phase 4
Phase 5
Phase 1:
LOESCHE discusses with you
sustainability strategies, regulations
and potential cost reductions through
the use of calcined clay. At the end of
phase 1, LOESCHE understands your
specific business goals and
requirements.
Phase 2:
LOESCHE tests the properties
and the important characteristics
of your clay in its own test center.
Moisture, fineness, and the
potential reactivity are analyzed.
The existing auxiliary equipment
available and its conditions are
identified.
Phase 3:
LOESCHE analyses which
C/CLAY technology suits
the individual project across
commercial, sustainability and
quality goals.
Phase 4:
LOESCHE supports you
in the realization of your
C/CLAY project.
Phase 5:
LOESCHE will ensure the successful
operation of your calcined clay line by
providing service, optimization and spare
parts for the entire lifetime of the plant.

9. Refurbished kiln flash calciner
• low CapEx
• re-using retired rotary
kilns
• established technology
• robust process manage-
ment
• flexible in moisture, size
and quality of feed
material
• throughputs similar to
clinker capacity
New Rotary kiln
• few rotating parts need
low maintenance
• low civil engineering
investment costs
• low heat loss and energy
consumption
• more economical for high
throughputs
• well-known technology
• simple process
• flexible feed material
conditions
• efficient and sensitive
due to intelligent control
technology
• more economical for
smaller throughputs
SELECTING THE OPTIMUM CALCINATION AND
GRINDING TECHNOLOGY FOR YOUR PROJECT
Refurbished kiln
If you have a retired kiln available, LOESCHE can
help you to refurbish the existing kiln to meet your
project requirements. This is a sustainable and com-
petitive way to reduce total costs required compared
to a new calcination system. The refurbished kiln
offers the same advantages as new kilns: high
flexibility in feed quality and variable throughputs.
Flash calciner
A flash calciner is a vertical, multi-stage system
designed and configured for individual material
requirements. It offers sustainability, ease of operation
and space efficiency. In flash calcination, pre-ground
clay is heated rapidly, held at this temperature for a
short time, and then cooled rapidly. The gases
exiting the flash calciner system dry the raw clay,
which further reduces heat consumption and thus
increases flexibility in terms of alternative fuels.
Overall, this is a very cost-effective technology for
plants without existing kilns and for finer clays with a
moisture content of less than 30%.
The flash calcination process provides a higher fuel
consumption efficiency, but requires a feed size of
less than 2 mm, as flowability problems may occur
with larger particles.
Rotary kiln
The rotary kiln delivers the required calcination
temperature over a long residence time and is there-
fore more flexible in terms of particle size, but has
higher fuel consumption compared to a flash calciner.
LOESCHE supplies kiln technology for plants around
the globe. With its C/CLAY technology, LOESCHE
offers its customers operational reliability, cost
efficiency, sustainability and adaptability to alternative
fuel sources. C/CLAY allows to run variable through-
puts and can handle heterogeneous clays with high
moisture contents.

10. 10 | 11 Material testing
MATERIAL TESTING
LOESCHE ensures that your material is activated in an optimum way.
This includes:
• useful and robust pretreatment
• appropriate calcination conditions
LOESCHE tests different grinding processes for your clay in terms of
co-grinding and separate grinding with clinker and other supplementary
cementitious materials (SCMs).
Our large-scale testing is able to simulate industrial production with
on-site parameters as realistically as possible.
For both cement and concrete, application parameters such as strength,
workability and durability are tested and scientifically evaluated.
In LOESCHE’s full-service large-scale testing facilities your
material is activated in an optimum way.

11. LOESCHE TEST CENTER
Based in Neuss (Germany) our Test
Center is the heart of our R&D efforts.
Several fully automatic pilot-scale
grinding plants are available.
LOESCHE’s C/CLAY team
helps you select the optimum
system from raw material
handling, calcining and
grinding by analyzing all
available information during
project identification, material
analysis and testing.

12. 12 | 13 Color control
COLOR CONTROL
The color of calcined clay and the produced cement is important
for market acceptance.
During the calcination process, the clay turns reddish due to the oxidation of iron.
This also influences the color of the final product. However, the color of the cement
is important for its acceptance in the market. Therefore, Dynamis has developed a
patented color control system to prevent iron oxidation (where necessary). Color
control is achieved by preventing the conversion of magnetite to hematite. The
color can be controlled under stochiometric burning conditions in a reductive envi-
ronment.
AsuccesfulColorcontrolismostimportantformarketacceptance.
Additionally,desulfurization,denitrificationandthermaloxidationaremandatory
forenvironmentalhealthandsafetyandasubstantialpartofallC/CLAYsolutions.
Calcined clay
without color control
containing hematite
Calcined clay
with color control
containing magnetite
Magnetite
(Fe3
O4
)
Hematite
(Fe2
O3
)

13. The advantages of co-grinding in a
LOESCHE vertical roller mill are:
• no mixing required
• 25 % less grinding energy
required
• 7 % increase in compressive
strength
Comparing separate and Co-Grinding
After calcination and optimal activation of the clay, sufficient and efficient grinding is
essential to get the best out of the material. Therefore, LOESCHE has long focused
on both separate and co-grinding. A case study with African clay gives more insight.
EFFECTIVE GRINDING
IS ESSENTIAL
Separate grinding Co-grinding
Cement mix 80 % clinker + 20 % clay
Fineness 5,050 Blaine
(clinker: 4,200 cm2
/g,
clay: 8,100 cm2
/g)
d50
= 6.1 µm
5,160 Blaine
d50
= 9.2 µm
Specific energy 22.4 kWh/t 16.7 kWh/t
Compressive
strength
(28 days)
60.7 MPa 64.7 MPa
- 25 %
+ 7 %
Purity of fines
feed
best result
feed fines 1 fines 2 fines 3 fines 4 fines 5 fines 6
material
quartz content clayish content
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Quartz separation
An additional approach is the separation of quartz as an inactive component. Due
to the selective grinding in the LOESCHE mill, a quartz reduction of more than 50
% is possible, as can be seen in the table to the right. This can be executed before
or after calcination.
The advantages of quartz separation
are:
• clay enrichment
• better burnability
• better heat transition
• less energy consumption
• better reactivity index
• better cement and concrete
performance
Table (right): example of co-grinding
compared to separate grinding

14. 14 | 15 Case study
THINK BIG...
Dynamis built the worldwide biggest calcined clay line in
Rio Claro, Colombia.
The target
The goal was to design a 1,500 tpd calcined clay production line from a
decommissioned kiln while addressing the following challenges:
1. producing high quality cement from low-quality clay
2. ensuring signature cement grey coloring from reddish clay
3. optimizing CapEx spend by using existing plant components
The approach
1. Using the refurbished rotary cooler to:
• manage capacity mismatch with D-Dryer using flue gas from the rotary kiln
• accommodate for gas velocity in kiln by installing D-Hotgas generators
2. Using the proprietary D-Gasifier to
• reduce cost through solid fuel intake of coal, petcoke and biomass
• match the tight needed temperature range
• ensure safety and quality with high flame stability
3. Installing color control through oxygen supply in the kiln atmosphere

15. The impact
The customer Argos looks proudly on the project and states:
• cement, which “maintains the quality and performance that have always
characterized the company”
• up to 38 % emission reduction
• up to 30 % reduction in energy consumption
• 450,000 t/y installed capacity of the new clay thermal activation line
Process parameters, Rio Claro
Production of calcinator 1,400 tpd
Clay feed 80 t/h
Feed moisture 20 %

16. LOESCHE is an export-oriented company, established
in Berlin in 1906, which is up-to-date run by the owner.
Today the company is internationally active with sub­
sidiaries,
representatives and agencies worldwide.
CLOSE TO YOU
Contact us to learn more about C/CLAY @ LOESCHE
via c-clay@loesche.com
www.loesche.com
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