Grups cement

Hasannudin

0900309

Rikapurnama

sari0902024

Fitri nurbaras

ari0909025

Citra mutiara A0905660

Pend.kimia A

Industrial chemistry

Hasannudin0900309

 Cement comes from word “Caementum” which means a substance which has the function as an adhesive between two or more ingredients become a part of a cohesive or adhesive material between the rocks of building construction

1 . Definition of Cement

lime stone (CaO) as the main source, sometimes polluted by SiO2, Al2O3, and Fe2O3

Clay-containing compounds SiO2, Al2O3, and Fe2O3

Quartz / silica stone, is added if the clay containing small SiO2.

Iron ore, is added if the clay containing small Fe2O3

principal elements of cement

the kinds of cementPortland cementPozzolan cementHigh alumina cementSilicate cementSulfur cementPolymer concreteSorel cement

Portland cement is hydraulic cement that`s produced from grinding clinker with additive material

Portland cement is applied in all kinds of informing against like foundation,palm, and,wall retainer, road

main material of cement portland, are:CaCO3 : 60 % - 65 SiO : 20 % - 25 %Fe2O3 and Al2O3 : 7 % - 12 %

Portland Cement

Type 1 (ordinary portland cement)Ordinary portland cement is used for all kind of construction and contain 5% MgO and 2.5-3 % SO3.

Type 2 (moderate heat of hardening)Moderate heat portland cement is used for construction that requires the use of resistance to sulfate and medium calor hidration.Moderate heat portland cement contain 20% SiO2, 6% Al2O3, 6 % Fe2O3, 6% MgO , 8% C3A

Type 3 (high early strength)high early strength cement contain 3.5-4.5% Al2O3, 6% MgO , 15% C3A, 35% C3S, 40% C2S.High Early Strength Cement is commonly specified where higher than normal early strengths are required

the types of portland cement

Type 4 (Low Heat Cement)It is manufactured from the ingredients of specially selected cement clinker and ground granulated blast furnace slag, that result in significantly lower heat generation during the process of hydration than the comparable Portland Cement.

type5It is manufactured from the ingredients of specially selected cement clinker and ground granulated blast furnace slag, combining the benefits of significantly lower heat evolution, greater sulphate, chloride and salt water resistance.Sulphate Resisting Cement may be used in marine applications, in mass concrete where reduced heat liberation is important or in aggressive sulphate-rich environments where increased resistance to salt attack is required.

the types of portland cement…cont`d

Carachterization of cement materials

Character of cement Portland :1. Hydration of cement :a. Hydration of Alite (C2S,C3S)b. Hydration of C3A c. Hydration of C4AF2. Setting and hardening3.Temperature of hydration4.Decrease : - Drying shringkage - Hydration shringkage - Carbonation of shringkage5.Dampness : - Loss on ignation (loses dawn) -Specific of gravity - False set

Carachterization of cement materials

1. Cement hydration A reaction between cement components and water. To know more about hydration cement, it must recognize hydrasion of compounds contained in cement (C2S, C3S, C3A, C4AF)

a. Hiydration Calcium Silicate (C2S, C3S) Calcium Silicate in water into Ca (OH) 2 and calcium silicate hydrate (3CaO.2SiO2.3H2O) at 30⁰C

Carachterization of cement materials (cont`d)

b. Hydration C3AHidration C3A with excessive water at 30⁰C will produce hydrate alumina calcium.which it’s the crystal is cubic in cement because of the gypsum so that the result of hydration C3A is quite differs.

c. Hydration C4AF (H2O 30 ⁰C) 4CaO. Al2O3. Fe2O3 + 2Ca (OH) 2 +10 H2O 4CaO.Al2O3.6H2O + 3CaO.Fe2O3.6H2O

Carachterization of cement materials (cont`d)

2. Setting and HardeningSetting and Hardening of cement is cordage and terrace of cement. Cement if mixed with water will produce pasta which plastis and workable until some times characteristic from pasta doesn’t change and this period often is called as Dorman period or sleep period.

f. Heat Hiderasi Hiderasi heat is the heat released during cement experienced hiderasi process. Amount of heat that terajdi hiderasi dependent, type of cement, fineness of cement, and a comparison between the water with cement. Cement of high initial hardness and heat are likely hiderasi terajadi cracks in concrete, it is caused by the phosphorus is removed so that the resulting difficulty terajdi expansion in the cooling process.

g. Shrinkage There are three kinds of shrinkage that occurs in the cement, among others: Shringkage drying (drying shrinkage karean) Hideration Shringkage (penyuautan because hiderasi) Carbonation Shringkage (penyuautan because carbonation) The most influence on the concrete surface is Shringkage Drying, shrinkage occurs due to evaporation during the process of setting and hardening. Bial amount of moisture can be maintained, then the concrete cracks can be avoided. Depreciation is also dioengaruhi C3A content is too high.

h. Humidity Humidity arises because the cement absorbs water and CO2 ¬ uap and considerable amounts of clotting sehigga happen. Lumpy semen quality will decline because of increasing Loss On Ignition (LOI) and reduced specific gravity so that the strength of cement decreased, setting time and hardening the longer, and the occurrence of false set.

Loss On Ignation (Lost Dawn) Loss On Ignation required to prevent the presence of minerals, which decompose at the time mneral pemijaran, where this process is causing damage to the stone after a few years later.

i. Specific Gravity Specific gravity of cement is very important information in the design of concrete. Quality control within the Specific gravity is used to determine how far the perfection of clinker burning, and also find out whether the clinker is mixed with impuritis.

j. False Set The process that occurs when the dough to harden overnight. False Set can be avoided by protecting the cement from the influence of outside air, so that the alkali carbonate is not formed within the cement.

Initial and final setting time in cement in practice very important, because early binding time will determine the length of time in which the cement mixture is still plastic. The minimum initial binding time of 45 minutes while the maximum 8-hour final time. Hardening reaction C2S C2S + 5H2O. 5H2O C3S + 5H2O C2S6. 5H2O + 13 Ca (OH) 2 C3A C3A + 3Cs + 32H2O. 3Cs + .32 H2O C4AF C3A.6 7H2O + H2O + CF. H2O MgO + H2O Mg (OH) 2

Cement can be made by two ways • Wet Process • Dry Process

The difference only lies in the process milling and homogenization.

CEMENT MAKING PROCESS

1. Quarry (MINING) Mining materials such as limestone, silica stone, clay, and other materials containing calcium, silicon, aluminum, and iron oxide which diekstarksi using drilling and blasting.

CEMENT MAKING PROCESS COND’T

• Peeling (stripping) Discard the top layer of soil • Drilling Make a hole with a drill to place Blasting • Blasting (explosives) With electrical engineering detonation.

Limestone Quarry

Silica mining does not require blasting for silica rock grains which are disjoint and not tied to one another. Mining is done by pushing the rock silica using a dozer to the edge of a cliff and fell in loading area.

Silica stone mining

Clay mining Done by dredging in the layer soil surface with an excavator begins with the construction of roads with sewer system of alternating intervals.

Clay mining

Solving materials, the results of mining becomes more sizes using a small crusher. Limestone from the size of <1 m → <50 m Silica stone of size <40 cm → <200 mm

2.Crushing

Raw material transported from mining area to manufacturing site for further processing using conveyor belt.

3. CONVEYING

Wet Process

      In the raw mill grinding done by adding a slurry of water and then produced with 34-38% moisture content. Water plus materials is fed into the raw mill. Because of the rotation, the material will move from one room to the nexr room. At the first room take solving process. At rooms 2- 3 occurred friction so that the mixture of raw materials into slurry.

4. RAW MILL

• Dry Process

       Occurred in Mill consisting Duodan       of Drying Chamber, Compt first and second Compt. Materials are entered along with hot gas from cooling towers and suspension preheater. In the room there is a filter dryer which serves to transport and scattering material so that the hot gas and contaminated material evenly so that the efficiency can be achieved. The separation of coarse and fine material in the separator.

• Wet Process     Slurry is mixed in the mixing basin. then the slurry is entered into the tube correction; process of correcting. • Dry Process     Occurs in the blending silos with funnel-flow system.

5. HOMOGENIZATION

Occurs in the kiln. Kiln is a tube-shaped device in which there were bursts of fire. Kiln in design to maximize the efficiency of heat transfer from combustion of fuel.

6. COMBUSTION/ CLINKER FORMATION

Fuel Preparation • Milling • Drying

FORMATION clinker The process that occurs in the kiln: • Drying Slurry • Home Heating • Calcination • Incandescenting• Refrigeration • Clinker Storage

Occurs at one third length from the inlet of the kiln at a temperature of 100-500 ◦ C, resulting in the release of free water and bound water to get the dry soil solids.

DRYING SLURRY

Home Heating Occurs at one third the length of the kiln from the inlet. During the heating was not changing the weight of the material but only the increase in temperature to about 600 ° C using a preheater.

HOME HEATING

• Degradation of calcium carbonate into the constituent compounds at a temperature of 600 0 C. • CaCO3 → CaO + CO2 • MgCO3 → MgO + CO2

CALCINATION

COOLING • Clinker cooling occurred suddenly with the air flow so that the size Clinker 1150-1250 g / liter. • Clinker Cooler temperature coming out of 150-250 ° C.

TRANSPORTATION & STORAGE clinker

    Will fall into the coarse clinker mill to grind. Then with a drag chain, which has been crushed clinker is transported to the clinker silo or directly to the cement mill for further processing into cement.

• The reaction between oxides contained in the material that forms compounds that hydrolysis C4AF, C3A, C2S at a temperature of 1450 ° C to form Clinker.

IncandescentING

An end milling process where take place clinkers with 5% natural or synthetic gypsum. In general, divided into three processes: • Grinding of clinker • Mixing • Refrigeration

Cement MILL

decreasing soil water availabilityIncreasing the number of CO2

Spreading the ash into the air and it cause respiratory diseases

noise pollutionreduced diversity of flora

impact of cement industry

a. Applying the pattern of blended cement production could reduce half the CO2 emissions

b. Changing some of the material in cement production with more environmentally friendly materials

Countermeasures

The end