Showing posts from August, 2013

Wet process - Cement manufacturing -Flow Diagram


Cement manufacturing is done in the following three major processes:
(a) Mixing
(b) Burning
(c) Grinding

(a) Mixing: Mixing can be done in two ways: (1) dry method and    (2) wet method.
Dry method was used in the early periods in between 1913 to 1982. After 1982 all the cement manufacturing plants in India are equipped with the technologies of Dry process, since this is more energy efficient and environment friendly method of cement manufacturing. In this post I am sharing with you the flow diagram of the wet process of the mixing because it is in the syllabus of the many Diploma courses.

Functions of various Constituents of Cement

Functions of various cement ingredients:
Lime (CaO) :This is the important ingredient of cement and its proportion is to be carefully maintained.  The lime in excess makes the cement unsound and cause the expansion and disintegration of the cement. On the other hand if the lime is deficient it will decrease the strength of the cement and will cause it to set quickly.Silica (SiO2) :   This is an important ingredient of the cement as it imparts strength to the cement due to formation of di-          calcium silicate and tri-calcium silicate. If silica is present in excess quantity its setting time is prolonged          however strength is increased.Alumina (Al2O3) :      This ingredient imparts quick setting property  to the cement. It acts as a flux and it lowers the clinkering        temperature. However the high temperature is essential for the formation of a suitable type of cement and       hence in alumina should not be present in excess amount as it weakens cement.Calcium Sulphate…

Bricks Classification and Specification (IS-1077:1992)

According to Indian standard(IS: 1077: 1992) bricks are classified into the following categories: Classes of common burnt clay bricks:       Class Designation             Average compressive strength not less than[ (N/mm^2) (kg/cm2)
35                                               35            35030                                              30                30025                                              25             25020                                              20                20017.5                                           17.5          17515                                              15                15012.5                                           12.5              12510                                               10                1007.5                                              7.5               75 5                                                5                   50 3.5                                            3.5                35
General Qualit…

Drying, Burning of Bricks- Bull's Trench Kiln, Hoffman's kiln


The Manufacturing of bricks is consists of  following processes:

 Preparation of brick clay Moulding of Bricks DryingBurning of bricks First two operations are already discussed in the previous two parts of the article in the same blog. In this blog I am going to discuss with you the Drying and the Burning of the bricks:
Drying Of Bricks: 
Drying of the bricks at lower temperature is done to strengthen the bricks to have sufficient strength so that they do not crack or crumble while holding and carrying them in hand. Finally bricks are to be stacked in the kiln, but they must possess the sufficient strength to maintain their shape while the transportation and loading operations, so drying of the bricks is important process. Drying of the bricks can be done in two ways:

(a) Natural Drying: Natural drying is done by putting the bricks in the under the air circulation, generally avoided to direct Sun-light.

(b) Artificial Drying: In artificial burning bricks are put under a temperature of…

Manufacturing of Bricks -part II (Moulding and Drying)

Preparation of the brick clay is already discussed in the earlier post, is this post I am going to discuss the second operation of brick manufacturing i.e. Moulding
Moulding: Moulding of the bricks into the proper shape and size can be done manually with the hands or it can be done with the help of machines. Hand moulding can take more time as compare to the machine moulding. Hand moulding is employed when the cheap labor available to us and less numbers of bricks are required to be manufactured and machine moulding can be employed when the labor is costly and the large numbers of bricks are required. Machine moulding is more accurate than the hand moulding.
Hand Moulding: It is again can be done in the following two manners: (a) Moulding on the ground. (b) Moulding on the table
In hand moulding on the ground following instruments are used:        (a) Mould        (b) Pallet        (c) Strike        (d) Clay Mould of the size about 10 to 12% greater dimensions than the standard brick size fo…

Manufacturing of Bricks - Part I (Preparation of brick clay)

Hello there,
how you doing? Please read on:

Manufacturing of bricks Selection of the brick field: Selection of the brick field where you have to establish your small scale  industry is done correctly when you check the following things:

 Site should be well connected with the road transportation facilities so as to transport your product.There should be plenty of the clay available which is to be used for the manufacturing of the bricks.All the necessary facilities for the workers should be checked and made available before starting the work.Site should be of plane topography. After the site selection and establishing the plant you can carry the manufacturing process in the following four processes:
 Preparation of the brick earth MouldingDryingBurning

Preparation of the brick clay:   Preparation of the brick clay can be done by completing the following processes: (1) Un-soiling (2) Digging (3) Cleaning (4) Weathering (5) Blending (6) Tempering
(Ref: Civil Engineering materials by Rangawala…

Composition of a Good Brick Earth

Hello There, How you doing? Well, here is what you searched for:

Composition of a good brick earth:
Following are the constituents of a good brick earth:
(1)Alumina (Al2O3):
It is the chief constituent of a good brick earth. A content of about 20% to 30% is necessary to form the brick earth of a good quality. It imparts plasticity to the earth so it helps in the moulding of the brick earth.  If alumina is present in excess with inadequate quantity of sand then the raw bricks shrink and warp during drying, on burning they become too hard. So it is important to have an optimum content of alumina.
(2)Silica (SiO2):
It exists in the brick earth either free or combined. As free sand it is mechanically mixed with clay and in combined form it exists in chemical composition with alumina. A good brick earth should contain about 50% to 60% of silica. 

The presence of this constituent prevents the shrinkage, cracking and warping of raw bricks. It thus imparts uniform shape to the bricks. The durability…

Introduction of Bricks - Brickwork superior or inferior to stonework??

Bricks: General: The bricks are manufactured by moulding the clay in the rectangular blocks of uniform size and then by drying and burning these blocks. Bricks are easy to work with because of their uniform size and light weight. They do not require the dressing and the brickwork can be done by the non-skilled workers. Stones are not easily available so if clay is available bricks can be manufactured and utilized. The bricks are very old Civil engineering material which were utilized in many historical buildings of the Roman Empire and also in the Chinese Civilization burnt bricks and Sun dried bricks were utilized to construct the Great Wall of China (210 B.C.). Wood was used earlier but due to its fire catching risks it was replaced with the bricks. The great fire of the London in 1666, converted the city from the wooden city to the brick city. According to the data provided in a book titled “Engineering Materials” by India has more than about 45000 local kilns and has a capacity of…

Uses of Stones

Uses of Stones: The stones are used in the construction of buildings from the ancient times and most of the ancient temples, forts and mosques of India were built with stones as the major material. The Taj Mahal, Red Fort, Jama Masjid, Parliament house and Rashtrapati Bhawan at Delhi and various other prominent structures spread throughout the length and breadth of our country furnish us the awesome examples of uses of the stone as building material. At present, they are largely used as the basic material for the manufacturing of the other construction materials like concrete, bricks etc. Following are the various uses to which stones are employed:- Structural elements: The stones are used for foundations, walls, columns, lintels, roofs, floor, damp proof courses etc. Facing: The stones are adopted to give massive appearance to the structure. The walls are of bricks and facing is done in stones of desired shades. This is known as the composite masonry. Paving: The stones are …

General characteristics of marble, Kota stone, granite, basalt etc

You can/may find here the following stone's characteristics discussed below:
(1) Marble (2) Limestone (3) Sandstone (4) Granite (5) Basalt (6) Slate  (7) Kota Stone

(1) Marble: (a)Marble is a metamorphic rock formed    after after the metamorphism of the limestone. Under high temperature and pressure, re-crystallization of  calcite and dolomite takes place to a compact structure.
(b) It is largely used for the ornamental, carvings and molding works.
(c) It is available in many color from white to black including, red, green, yellow, blue and gray.
(d) It is porous to some degree and more after getting the polish.
(e) It has lustrous and glossy appearance.
(f) It is used as flooring, wall linings, table roofs, bath tubs, and sculpture making etc.
(g) Limestone(CaCO3) being the main compound it is liable to acid attacks, if MgCO3 is the major constituent then it is more acid resistant.
(h) Its specific gravity is 2.72
(i) Its crushing strength varies from 50 to 60 MN/m2

(2) Limestone:(a)Lime…

Types of Cement

Cement is a Civil Engineering Material which is worldwide used to form concrete and mortar and other soil stabilization works. It is  possible after the invention of the cement to get the structures with high strength and of various attractive architectural shapes at the same time. The strength of cement depends on its constituents and their relative proportions.
1.Ordinary Portland Cement: Ordinary Portland Cement(OPC) is used for the normal concrete works. It has cohesive and adhesive properties when mixed with water. After the evaporation of water it forms a solid mass. OPC manufactured by burning the following materials in a definite proportion: (a) Siliceous Materials  (b) Argillaceous Material (containing clay) (c) Calcareous material (Containing Lime)  The mixture of the above constituents is burnt to a temperature of about 1400 degrees celcius in the Rotary kiln which results in the formation of the clinker.  The clinkers so obtained are cooled and crushed to form the powder f…