Claims:We Claim:

1. A method for preparing a wall plaster, the method comprising steps of:
collecting raw slag having non-metallic glass composed of silicates and alumina silicates of lime which is obtained as a by-product from a metal smelting process;
drying the collected raw slag in a sand dryer;
crushing the dried raw slag in a crusher;
mixing the cement, a polymer and the crushed slag in a first predefined weight ratio for obtaining a mixture;
storing the obtained mixture in dry environment; and
mixing the dried mixture and water in a second predefined weight ratio for obtaining the wall plaster.

2. The method as claimed in claim 1, wherein the crusher is a triple cylinder roller crusher.

3. The method as claimed in claim 1, wherein the weight percentage of the cement in the first predefined weight ratio is 21.5 to 22.5.

4. The method as claimed in claim 1, wherein the weight percentage of the polymer in the first predefined weight ratio is 0.10 to 0.15.

5. The method as claimed in claim 1, wherein the weight percentage of the crushed raw slag in the first predefined weight ratio is 77 to 79.

6. The method as claimed in claim 1, wherein the percentage of water in the second predefined weight ratio is 18 to 20.

7. The method as claimed in claim 1, wherein the raw slag is free from the materials reducing strength of the wall plaster.

8. The method as claimed in claim 4, wherein the polymer is methyl hydroxyethyl cellulose.

9. The method as claimed in claim 7, wherein the materials reducing strength of the wall plaster are Mortar or chlorides or organic components or clay or silt or shells or combinations of these.

10. The method as claimed in claim 8, wherein the polymer possesses viscosity in the range from 40000 to 60000 millipascal second (mPa-s) when the viscosity is measured through a Brookfield viscometer.
, Description:Field of the invention

The present invention relates to a method for preparing a plaster. More particularly, the present invention relates to a method for preparing a plaster for walls.

Background of the invention:

Plasters are generally applied on walls of the buildings to protect them from moisture, dust and other similar elements. Also, the plasters can be used for creating decorative forms on the walls. Some plasters provide smooth surface finish to the walls.
Plastering is a method for covering rough surfaces of building components, such as walls and ceilings with a coat of plaster to form a smooth and durable surface. Adherences to the substrate (should remain adhered during all Climatic Changes), adequate Strength, cost effective, resistance to penetration of water, hardness and durability, easiness to apply on walls during all weather conditions are some of the desired properties (characteristics) of a good wall plaster.

Furthermore, the existing plasters cannot be applied with thicker layer in a single operation. For coating thicker coats, a first layer of coating needs to be applied. Further a second layer coating is applied on the first layer. For applying the second layer coating, the first layer of coating must be cured (dried). Curing of the first layer coat requires some duration of time. This time delay is increasing cost of coating and increasing the wastage of the wall plaster.

Therefore, there is a need of a wall plaster, which overcomes the above-mentioned drawbacks of the existing wall plasters.

Objects of the invention

Object of the present invention is to provide a method for preparing a wall plaster.

Another object of the present invention is to provide a method for preparing a wall plaster, which requires less time for curing compared to existing wall plasters.

One more object of the present invention is to provide a method for preparing a wall plaster, which is cured by natural air curing.

Yet another object the present invention is to provide a method for preparing a wall plaster, which is ecofriendly.

One more object of the present invention is to provide a method for preparing a wall plaster, which is simple and economical in operation.

Summary of the invention:

According to present invention, a method for preparing a wall plaster is provided. The method includes step of collecting raw slag having non-metallic glass composed of silicates and alumina silicates of lime, which is obtained as a by-product from a metal smelting process. The metal smelting process is carried out in a steel processing plant for making steel. The collected raw slag is dried in a sand dryer. The raw slag is free from materials reducing strength of the wall such as Mortar, chlorides, organic components, clay, silt, shells and combinations of these.

The dried raw slag is crushed in a crusher. The crusher used for crushing the raw slag is a triple cylinder roller crusher. The cement, a polymer and the crushed raw slag are mixed in a first predefined weight ratio for obtaining a mixture. In the first predefined weight ratio, the weight of the cement is in range from 21.5% to 22%, the polymer is in range from 0.10% to 0.15% and the crushed slag is in range from 77% to 79% of the total weight of the mixture. The polymer is methyl hydroxyethyl cellulose. The polymer possesses viscosity in the range between 40000 to 60000 millipascal second (mPa-s), when the viscosity is measured through a Brookfield viscometer.

The obtained mixture is stored in dry environment. The dried mixture and water are mixed in a predefined second weight ratio for obtaining the wall plaster. The percentage of water in a second predefined weight ratio is from 18 to 20 of the total weight of the wall plaster.

Brief Description of drawings:

The advantages and features of the present invention will be understood better with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

Figure 1 shows a flowchart of a method for preparing a wall plaster in accordance with present invention; and

Figure 2 shows an image of a wall plaster prepared from the method of figure 1.

Detailed description of the invention

An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms

The present invention provides a method for preparing a wall plaster. The wall plaster prepared requires less time for curing compared to existing wall platers. The wall plaster can be cured by natural air curing. Further, the wall plaster is ecofriendly. Furthermore, the method is simple and economical in operation.

Referring now to figure 1, a flowchart of the method 100 for preparing a wall plaster in accordance with the present invention is illustrated.

The method 100 starts at step 10.

At step 20, the raw slag is collected. The raw slag is having non-metallic glass composed of silicates and alumina silicates of lime. Generally, non-metallic glass composed of silicates and alumina silicates of lime is obtained as a by-product from a metal smelting process. The metal smelting process is carried out in a steel processing plant for making steel. In the present embodiment, the raw slag is collected from the steel processing plant. The raw slag is free from materials reducing strength of the wall plaster such as Mortar, chlorides, organic components, clay, silt, shells and the like.

At step 30, the collected raw slag is dried in a sand dryer (not shown). The sand dryer is a machine used to remove moisture from the sand using general heating techniques. The collected raw slag is subjected to the sand dryer and dried. It may be obvious to person skilled in the art to use the sand dryer for drying the raw slag. The sand dryer removes the moisture content present in the raw slag.

At step 40, the dried slag is crushed in a crusher (not shown). The crusher is a machine used for crushing raw materials to produce finely crushed materials. In the present embodiment, the crusher is a triple cylinder roller crusher. It may be obvious to person ordinarily skilled in the art to use the roller crusher for crushing the slag. In an alternative embodiment, the crusher can be any machinery which crushes the raw slag. The distance between the rollers of the triple cylinder roller crusher are adjusted for obtaining relevant grain of the slag having a fixed value of fineness modulus and flakiness Index. The strength of the wall plaster depends upon the value of fineness modulus and the flakiness index.

At step 50, the cement, a polymer and the crushed slag are mixed in a first predefined weight ratio for obtaining a mixture. The weight percentage of the cement in the first predefined weight ratio is 21.5 to 22.5 of the total weight of the mixture. The cement used to prepare the mixture is an ordinary Portland Cement. The weight percentage of the polymer in the first predefined weight ratio is 0.10 to 0.15 the total weight of the mixture. The polymer is a special polymer having adhesion and Self Curing Properties.

In the present embodiment, the polymer is methyl hydroxyethyl cellulose. The polymer possesses viscosity in the range between 40000 to 60000 millipascal second (mPa-s), when the viscosity is measured through a Brookfield viscometer. The dosage and the viscosity of the polymer varies in the stipulated range considering the seasonal variations. The weight percentage of the crushed raw slag in the first predefined weight ratio is 77 to 79 of the total weight of the mixture.

At step 60, the obtained mixture is stored in dry environment. The mixture can be stored in a bag, which restricts the entry of moisture from outside to the mixture stored therein. The bag can be made of Polyethylene. The shelf life of the mixture is nearly about six months if the mixture is stored in dry environment.

At step 70, the dried mixture and water are mixed in the second predefined weight ratio for obtaining the wall plaster. The percentage of water in the second predefined weight ratio is 18 to 20 of the total weight of the wall plaster. Mixing can be done either manually or with a mechanical mixer or stirrer. It is advisable to use the mechanical mixer to get a homogeneous mix. Before applying the wall plaster, surface of the walls must be free from dust or loose particles, grease, mould oil, rust metal, wood peels, paints, plastics and the like.

Further, surface of the walls must be dampened or moistened with the water. While applying the wall plaster, stagnant or frequent water flow on substrate should be avoided. The wall Plaster can be applied by manually or through a spraying machine. For applying wall plaster through the spraying machine the percentage of water should be in the range of 22-24 of total weight of the wall plaster. The wall plaster can be applied on the surface of the walls up to 20mm in thickness in a single coat operation.

The method ends at step 80.

Now referring to figure 2; a sample plaster 12 (from herein after referred as a plaster 12) is prepared by the method 100. The Raw slag is collected from a steel manufacturing plant at step 10. Table 1 shows properties of collected raw slag from the steel manufacturing plant.

Sr no Property/characteristic Value
1 Loose bulk density in kilogram/litre 1.2 to1.3
2 Specific gravity 2.7
3 Percentage of slit, wet sieving <1.5
4 Inorganic coating (opal, gypsum or any other easily soluble salt) None
5 Organic coating None
6 Deleterious material (Strained quartz and other reactive minerals) None
7 Expansive mineral None
8 Percentage of Calcium oxide (CaO) 34.3
9 Percentage of Silicon oxide (SiO2) 36.01
10 Percentage of Aluminium oxide (Al2O3) 17.29
11 Percentage of Magnesium oxide (MgO) 6.03
12 Percentage of Iron oxide (Fe2O3) 0.73
Table 1
The raw slag having above mentioned properties are subjected to step 20, 30 and 40. At step 50, the processed raw slag, the cement and the polymer are mixed in a weight ratio of 77.5: 21.5: 0.10 respectively for obtaining a mixture. The mixture is subjected to step 60 and step 70 to obtain the plaster 12.

The plaster 12 is subjected to a testing operation. The testing is carried out by a regulatory authority. Table 2 shows properties of the plaster 12
Sr no Property/ characteristic Test result Test method
1 Bulk density in
kg/m3 cube
Loose
Rodded

1543
1767 Laboratory developed method
2 Pot life in minutes 60 Laboratory developed method
3 Compressive strength (N/mm2)
3days
7days
28days
7.6
11.1
15.9 IS 4031(Part 6)-1988
4 Drying shrinkage percentage 0.016 IS 4031(Part 10)-1988

Table 2
The plaster 12 does not include any air or water pollutants. Hence, the plaster 12 is eco-friendly in nature. The plaster 12 requires less time for curing compared to existing wall platers. The plaster 12 is cured by natural air curing and water curing also. The existing plasters require different kinds of material to manufacture which are obtained by mining and other chemical, metallurgical operations. The method 100 for preparing the plaster 12 does not involved with many metallurgical operations. Hence, the method 100 is reducing energy consumption required to make plasters.

Further, the plaster 12 can be coated on the surfaces of wall with a thickness of 20mm in a single coat operation which is not possible in case of the existing plasters. Also, rebounding of the plaster 12 while applying on the surface on the walls is less compared to existing plasters. As rebounding of the plaster 12 is less, the wastage of the plaster 12 while applying the plaster is also less. Furthermore, the method 100 is simple in operation. Also, the method 100 is economical in operation.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.