Cement (2024)

14/08/2023

Is there are any possibility that kiln inlet read actual CO on the other side there is excess O2 or high O2 at the kiln inlet ?!

Wait our full answer tomorrow, with another case.

$of refractory materials in cement rotary killn. • Before beginning we should satisfy the ...$

13/09/2020

of refractory materials in cement rotary killn.

• Before beginning we should satisfy the
following

▪︎ Safety for installation personnel.

▪︎ Maximize quality installation, that The bricks must be installed in such a way that the lining fits tightly against the kiln shell and subsequent loosening or twisting is impossible.

▪︎ Acceptable bricking progress.
This can also be improved by the use of fork-lift trucks, rollerconveyers and other equipment.

▪︎Installation of the bricks without damages and prevention of damage the bricks during installation.
▪︎ Correct arrangement of the joints

□ By studying the perivious criteria you should select the technique of installation the kiln bricks for example, the time planning, the safety, the quality and finally often the length of damage could help to select the technique required.

the ring bricks through correlations depends on the killn diameter.

• Start rings according to the indicated mixing ratio.

•Knock the bricks in place with rubber hammer Frequently check that rings are parallel to radiallines.

Important note.
always that cold face of brick is in full contact with kiln shell.

○ key bricks.

It is used to close the ring, the gap is measured and a combination of whole bricks and split ones are used to complete the ring Then steel shims are driven between the bricks to tighten the lining.

○ shell deformation
Some times a challenge for bricklayers is the shell deformation with mortar or castable. So it is necessary to clean the shell surface well before installation the bricks to prevent the bad quality of installation.

To be continued with the installation technique.

26/06/2020

The following posts will be focused on the killn thermal insulation:
The main point of view is the and the thought strategy at the perivious posts there were many critical points and another opinions about the the problems we show, so we would like to stand with the key words or references that the cases we show may not specified to your the problem occurring in your plant, that may happen due to many variable parameter as the plant design, the process operating, the material difference, and the strategy followed to over come problem
But in other cases such as the following one we are going step by step to help our audience the killn insulation.
Today we are standing at the entrance of

■ The unique conditions in cement manufacturing have always required specialized , especially now,
when more and more alternative fuels are used.

○ Know how ?

The key to establishing your question comes from specifying the problem so you can solve it step by once. Know how selection criteria.

● Top priorities for the cement industry today are to and solve the corrosion problems related to increased usage of alternative fuels.

● in the form of alkali pe*******on is unavoidable in cement production.
The worst damage occurs in lower cyclone stages and riser ducts, kiln inlets and even calciner.

So we are now standing in the opposite of two main problems in our industry thermo chemical attacking, and thermodynamics attacks.

¤ Thermo chemical attacks as result of the high process temp and the the material action.

¤ Thermodynamic attacks as a result of the process temp and the the fluidity material passing.

● preheater
• Cyclone stage 1
Refractory lining thickness: 114 mm
Insulating thickness: 38 mm
Process temp: ≈ 306°C
External shell temp: ≈ 70°C

• Cyclone stage 2
Refractory lining thickness: 114 mm
Insulating thickness: 50 mm
Process temp: ≈ 503°C
External shell temp: ≈ 83°C

• Cyclone stage 3
Refractory lining thickness: 114 mm
Insulating thickness: 64 mm
Process temp: ≈ 665°C
External shell temp: ≈ 93°C

• Cyclone stage 4
Refractory lining thickness: 114 mm
Insulating thickness: 76 mm
Process temp: ≈ 806°C
External shell temp: ≈ 101°C

• Cyclone stage 5
Refractory lining thickness: 114 mm
Insulating thickness: 76 mm
Process temp: ≈ 890°C
External shell temp: ≈ 109°C

● Heat transfer phenomena
As known for every one the driving force of heat transfer is the temperature difference.
Note that the driving force in mass transfer is the concentration difference.

Modes of heat transfer

1_ conduction
Apply for solid (single phase )

2_ convection
Applying between two phases for example fluid phase

3_ radiation
Apply between fluid and solid at very high temp
Or between gasses.

Shortly out needs is to save the heat energy inside the killn system and minimize losses as possible.

In our next posts we are going to focus on every part as shown in the pic attached and the selection of the refractory chemistry.

If you can share your problem & don't forget rating the page.

17/06/2020

Today we are going to speak about a very important point take place at the cement killn

Coating in the cement killn is a protective layer on the lining in the sintering zone in the killn.

Coating in the killn can be classified as the following:
1_ thick coating layer (30:50 Cm)
2_ noal coating layer (10:20 Cm)✅
3_ thin coating layer about (10 Cm)

Benefits of coating layer:
That layer have an important role to keep the killn performance as
1_ reduction the heat transfer by radiation (we will speak about this point with the killn isolation &refractory in details )
As a result for the perivious point we will protect the killn shell from the thermal load.
2_ reduction the wear and abrasion.
3_ protect the refractory from the chemical attack by the clinker liquid phase.

is a thermo chemcal process occurs by the reaction between the clinker materials with the refractory (spinal), also some studies refer to the the best coating can be expected with liquid phase range about (25:27%) with silica ratio about (2.3:2.8).

Operational parameters to influence and keep coating layer in stable conditions
1_ Flame shape, and also the type of fuel..
2_ sintering zone temp
3_ also keep the killn in a steady state operational parameters.

Short note
Keep the theoretical parameters as a reference and the real or operating parameters in the other side for example, the shell diameter, the type of kill cement produced....etc

Keep in touch with next post
● thermal insulation
● Heat transfer conditions
● materials

15/06/2020

Suggest a topic to discuss in the next post or select of the following:

1/ ball mill charge.
2/ killn bricks & selection criteria.
3/ trump curve and separator performance.

○ you can send your problem and we will search for help you.

08/06/2020

From inbox
" in our plant there a raw ball mill we observed that the distribution of the ball isn't stable for the mill length that the big balls take place at the mill out let"
This problem lead to big balls make the small size balls deformed and the mill grindability processes doesn't complete, so what is the reasons of this problem?

08/06/2020

Known that it is a coal mill feeding hopper
Describe the bic and the physical phenomena of material passage.

16/03/2020

God save the world from Corona virus 🤲

13/03/2020

Transportation cement killn bricks during annual maintenance using machine instead of man power.

11/03/2020

Could you please find the formula to calculate consumption of grinding media at cement ball mill?
Thank you...
It was our friend's question l..

11/03/2020

Hi every one
Really I respect all members that belong to such this industry, feel his efforts. It is a huge body brain load.
Really you are strong enough to be here.
Welcome every one

06/03/2020

Hi every one
Let your problem and wait our strategy to overcome it,
Don't forget rating us .✍

28/12/2019

1_ Rapid hardening cement (RHC)
2_ Quick-setting cement (QSC).
3_ low heat cement (LHC).
4- Sulphate-resisting cement (SRC).
5_ Blast furnace slag cement (BFSC).
6_ High-alumina cement (HAC).
7_ White cement (WC).
8_ Coloured cement (CC).
9_ Pozzolanic cement (PzC).
10_ Air-entraining cement (AEC).
11_ hydro phobic cement (HpC).

Finally the most known type of cement Ordinary Portland Cement.

Which type/s of cement your plant produces?

15/12/2019

Simply you can can calculate the maximum feed rate of cement mill through the following.
1- tube mill
Feed rate = (main drive power)/ 35

2_ vertical mill
Feed rate = (main drive power) / 25

18/11/2019

Here the yesterday's problem analysis, we see none could reach the main reason and satisfied the problem well.
This problem hasn't any operational reasons but that is cause of the difference chemical formation of iron ore & slag, which also has an affect of the temp of decomposition.
Slag has much impurities than iron ore, I think that's well known for the all here.
slag lead to kiln over heating and more sulfur evaporation lead to closed cycle ...check sulfur in clinker and liquid phase percentage..

17/11/2019

It was our page's friend question, check your information & share your knowledge with the others.
Send your question to the page messages .

26/10/2019

Today's discussion about the killn and cooler bricks ? What is the Composition should be? And the mechanism of matching each area with the specified bricks? .. let's start check your information ?

28/09/2019

Ball mill charge during annual maintenance " raw mill "🌌

16/09/2019

How can you reduce the cost in cement industry ?

31/08/2019

1- WHAT IS THE RELATION BETWEEN CEMENT QUALITY AND PRODUCTION COST ?
١- ما العلاقة بين جودة الأسمنت وتكلفة الصناعة ؟

________________________________________________

2_WHAT IS THE RATIO OF TOTAL CARBONATE "TC" IN THE RAW MEAL FEED ?

٢- نسبة الكربونات في المواد الخام ؟

________________________________________________

LET YOUR ANSWER IN A COMMENT AND SEND YOUR QUESTION INBOX, WAIT THE ANSWER TOMORROW.

اترك إجابتك في تعليق، وأرسل السؤال في رسائل الصفحة. انتظروا الإجابات غدا

22/08/2019

نبحث الآن خطة تعريب منشورات البيدج، أم نُكمِل بمواصلة اللغة الإنجليزية، أو الكتابة بالعربية والإنجليزية معا.
القرار متروك لكم.

21/08/2019

🤔

18/08/2019

- we are here for helping each other not to gain money, that's our message for the all .🌹
science is free.
Mention your job friend in cement industry.

16/08/2019

•• Do you think what happen for clinker when exposed to rain water?!

Firstly we didn't receive any answer for the previous question.

Before we show the effect of rain water on cement we are going to start a Nice discussion about dust collectors.
In another way what do you know about each of them?.

▪︎ a model answer will be shown tomorrow.
____________________________________________
____________________________________________

● The previous question answer.

_ when clinker exposed to rain water happen the following:

▪︎▪︎ As known strength of cement is simply because hydration of clinker on the application of cement with water.

▪︎▪︎ Hydration is irreversible reaction. hydrated clinker will be devoid of any strength so fresh clinker will become more and more hydrated the longer it is exposed to moisture, so it is important to keep it covered "theoretically".

▪︎▪︎If we add limestone as a filler in your cement, there is a solution to using partially weathered clinker without any drop in mortar strengths, as long as the L.O.I. of the weathered clinker is not greater than the contribution of the normal limestone filler content.

For example, if your GP cement normally contains say 5% of pure limestone as mineral filler and 5% gypsum, then your GP cement L.O.I. will be around 3.3%, using fresh clinker. This LOI includes;-

LOI contribution of fresh clinker = ~0.3%

LOI contribution of 5% gypsum = ~0.8%

LOI contribution of 5% limestone = ~2.2%

Water reacts with clinker minerals to produce Ca(OH)2. For example the reaction with C3S is;-
2(3CaO.SiO2) +7H2O --> 3CaO.2SiO2.4H2O + 3Ca(OH)2

▪︎▪︎Due to the large surface area of the clinker particles (and the open pores within them) the released Ca(OH)2 reacts fairly quickly with atmospheric CO2 to produce CaCO3 by the reaction;- Ca(OH)2 + CO2 --> CaCO3 + H2O Therefore what you are left with in weathered clinker is a reduced clinker mineral content and a correspondingly increased CaCO3 content. (measured by LOI).

▪︎▪︎If you are already adding CaCO3, in the form of limestone, it is a simple matter to reduce the amount of limestone mineral filler added to the cement, so as to just compensate for the extra CaCO3 in the weathered clinker. At the same time, reducing the amount of limestone filler has the effect of increasing the clinker mineral content back to its normal level.

Of course in the above example, using 5% limestone filler, it would not be possible to compensate for this extra CaCO3 if the LOI of the weathered clinker is greater than 2.2%.

Therefore, it is always best to keep your "outside" clinker covered. But if you are then forced to use it, and you already add limestone as a mineral filler, it is possible to use partially weathered clinker without any effect on mortar or concrete strengths.

You will need to continually test the LOI of the clinker being fed to the cement mill (after first drying it fully) and adjust the limestone feed according to the LOI result.

If it's useful rate us.
Send your question .
Contact the page.

13/08/2019

Hi, every one.
Yesterday's discussion was about "if there's a limited time for clinker before grinding? "

- here the main concept is the clinker temperature degree that has many effects on the final Cement properties.

_ The second concept that we should take of it especially when the ball mill are used that the temperature affects the slide shoe bearing.

Now today's question

What happened for clinker when exposed to rain water before grinding?

I wish that's helpful.

12/08/2019

The yesterday's question model answer

How can you control the free lime in the clinker "killn" ?

So let's start.
Now we are going to show the operator role, so firstly we can put the C3S is the basic variable in this problem.
So if the C3S is at the same ratio " operational target" and there is free lime so the problem is refer to the killn feed.

If the C3S isn't in target so the problem refers to operational problems.

I see the following answer is the model answer from the page friend Muhammad

First you shall know the main reason for higher free lime rates:-

1. Hard to burnt materials, then you have to increase fuel rate, decrease kiln speed, adjust cooler operation parameters, some times you are forced to decrease kiln feed rate, this is accompained by reverting the kiln feed analysis to its normal target.

2. Cold kiln atmosphere, then you have to increase fuel rate, decrease kiln speed.

3. Ball formation, then you have to increase kiln speed, reduce fuel rate, calcination degree and check if there is abnormal feed analysis.

4. Improper cooling at cooler inlet, then you have to adjust cooling efficiency.

5. Coat collapse, then you have to decresse kiln speed and adjust feed analysis.

6. Light material flushes of the PHT due to to coat formation and falling in the cyclones, also some times the flaps under cyclone get temporary stuck.

8. Incomplete combustion or localized reducing conditions, then adjust burner operation parameters.
....
Today's question:

Is there a limited time for clinker to stay before grinding?

● If it's helpful don't forget fo send your question to the page.

11/08/2019

Today's question "from the inbox"
How can you control the free lime in the clinker "killn" ?

Note:
The Mobel answer will be shown tomorrow at the same time. " don't forget send your question to the page messages" and wait the answer.

07/08/2019

●● Manufacturing of Portland Cement

Cement industry contains a very big number of details. On the other hand the main process stages are the same or similar to each other.

We are going to discuss as much as possible. Starting from the main stages.

▪︎Quarry
Quarry selection and quarrying process is the main criteria and the first step to the construction of cement plant, the quarry chemical and physical properties, nature, availability, etc. ( more details in the next articles).

After quarrying process the materials are with avery particle size, so we are going to reduce size with in the further process.

▪︎ Crushing
Crushing may be counted as the first step in the plant process as the materials delivered from the quarry has a very big particle size, then crushed into small sizes.
The crushing system and selection of crushers are constructed and selected the type of crushers referred to the type of materials nature.

■ Stacking and Reclaiming raw materials
Well calculations are done to obtain the raw mix bile with the specified properties (there are many systems introduced in details later)

▪︎ Grinding
Horizontal mills(tube mill, ball mill), or vertical mills are used in cement industry.The mix feed to the mill and adding the correction materials.
Using hot air to heat the materials and good lifting for the materials inside the mill.

▪︎ Pre Heating
Cyclone stages or numbers are determined to optimize the maximum target of integration for heat, also the design referred to the nature of raw materials.

Burning
Burning process take place in a rotary killn, where the temperature reaches about 1450 °C at the clinkering zone.

▪︎ Cement Mills

Cilncer from killn cooled, and converted to cement silos to feed the finish mills, adding about 5% gypsum.

●● Process in points

1_ The raw materials are reduced to fine particle size.

2_ Raw materials are blended and mixed to produce uniform chemical composition containing calcium carbonate, silica, alumina, iron oxide. Then stored in the the raw mix silo.

3_ The blended raw mix is heated to remove the moisture content.

4_The dried mix is heated to 800°C. Where , the calcium carbonate dissociated into calcium oxide (CaO), and carbondioxide (CO2).

5_with increasing temperature,active compounds of Portland cement is formed. This process is completed at a temperature of around 1400°C.

6_Clinker is cooled to a temperature of about 150°C.

7_Clinker is ground to the specified fineness with the addition of a small quantity of gypsum to control the setting time of the cement.

8_The finished cement is stored in silos.

Is it useful ? If it is Don't forget like page, read the previous notes.

9_ packing and marketing.

03/08/2019

Today we are going to show short notes(A,B C,D) about the Chemical Composition of Portland Cement.

A _ Raw Materials of Portland Cement:

1- Calcareous rocks (CaCO3 > 75% such as limestone, marl, chalk).

2- Argillaceous rocks (CaCO3 < 40% such as clay and shale).

3- Argillocalcareous rocks (40-75% CaCO3 such as clayey limestone, clayey marl).

Materials from any two of these groups may be used for Portland cement production providing that they must Contains and has proportions of lime, silica and alumina.

B_ Chemical Composition of Portland Cement:

The raw materials used in the manufactureing of Portland cement consist mainly of lime, silica, alumina and iron oxide.

1_ SO3 (sulfur trioxide): Comes from gypsum some times added as a correction material (sand) .The amount of gypsum (CaSO4.2H2O) can be approximated by multiplying the
amount of SO3 by 2.15.

2_ MgO (magnesia): To control the detrimental expansion. MgO is limited to 5% (expansion due to the hydration of free MgO in hardened concrete).

3_ Free CaO: The same as free MgO, free CaO is undesirable. Because these oxides hydrate much later than other compounds of
cement.
Also, show a large volume expansion after hydration resulting in disintegration of hardened concrete.

4_ Na2O & K2O (alkali oxides):A limiting value of alkali oxides is often specified for cement which are used with reactive aggregates to prevent alkali-aggregate reaction which
results in disruptive expansion.

5_ L.O.I. (loss on ignition):Indicates "prehydration or carbonation" due to prolonged or improper storage.
LOI is the loss of the weight of a cement sample when heated at
1000°C.

LOI

02/08/2019

_ History of Cement

The cementitious properties of lime in mortars and concrete have been known since early historic times.

The Romans used lime concrete and developed pozzolanic cements of lime and
certain volcanic earths.

After that, Lime mortars and concretes continued to be used in the middle Ages.
" John Smeaton" made an important contribution to the development of cement when he was planning the construction Lighthouse (1755) in the English Channel. He needed a hydraulic mortar that would set and develop some strength in the twelve hour period between.

• 1824, "Joseph Aspdin" produced a powder made from the calcined mixture of limestone and clay.
Aspidn called it "Portland Cement", because when it hardened it produced a material similar to stones from the quarries near "Portland Island in England".

Later in (1845) "Charles Johnson" burnt a mixture of clay and chalk till the clinkering stage to make better cement and established factories in 1851.

The German standard specification for Portland cement was drawn in 1877.

The British standard specification was first drawn up in 1904.
In India, Portland cement was first manufactured in 1904, by the South India.

Although the method of making cement has been improved, the basic process has remained the same.
Follow us and wait tomorrow's notes

01/08/2019

1.1 Introduction; Cement is a material used as a binder in constructions that mixed with water and sand, a substance that sets, hardens, and adheres to other materials to bind them together.

Cement

14/08/2023

13/09/2020

26/06/2020

17/06/2020

15/06/2020

08/06/2020

08/06/2020

16/03/2020

13/03/2020

11/03/2020

11/03/2020

06/03/2020

28/12/2019

15/12/2019

18/11/2019

17/11/2019

26/10/2019

28/09/2019

16/09/2019

31/08/2019

22/08/2019

21/08/2019

18/08/2019

16/08/2019

13/08/2019

12/08/2019

11/08/2019

07/08/2019

03/08/2019

02/08/2019

01/08/2019

Address

Telephone

Website

Alerts

Contact The Business

Shortcuts

Share