WO2020069590A1 - Ceramic coating composition, method for obtaining a ceramic coating base mass, use of the ceramic coating composition and ceramic panel - Google Patents

Abstract

The present invention describes a ceramic coating composition, wherein the composition comprises a mixture of inorganic materials and a solid chemical residue, wherein the solid chemical residue is a brine sludge. The present invention also describes a method for obtaining a ceramic coating base mass, the method comprising the steps of collecting the brine sludge; incorporating from 0.5% to 10.0% by weight of brine sludge into a ceramic mass containing inorganic materials, subsequently homogenizing the ceramic mass and the brine sludge; moistening the homogenous mixture, adding from 1.0% to 15%, more preferably 8.0%, by weight of water, based on the total weight of the moistened homogenous mixture; total or partial drying of the moistened homogenous mixture, obtaining a dry homogenous mixture in granulate form and with a low moisture content; pressing in order to obtain a ceramic coating base mass using a compacting pressure in the range between 180 and 260 Kgf/cm2; and thermal treatment of the ceramic coating base mass at a temperature in the range from 800°C to 1650°C for a period of time of from 20 to 75 minutes and cooling to temperatures in the range of 100°C to 350°C. The present invention also relates to the use of the ceramic coating composition in civil construction and to ceramic panels.

Description

 COMPOSITION FOR CERAMIC COATING, METHOD OF OBTAINING A BASE MASS FOR CERAMIC COATING, USE OF THE COMPOSITION FOR CERAMIC COATING AND CERAMIC PLATE.

 FIELD OF THE INVENTION

 The present invention relates to a ceramic coating composition comprising a mixture of inorganic materials and a solid chemical residue called brine slurry (RSTS). Brine sludge (RSTS) is a solid chemical residue resulting from the treatment of brine that precedes the sodium chloride (NaCl) electrolysis process in the chlorine soda industry.

 The present invention also relates to a method of obtaining a base mass for ceramic coating, wherein the method comprises incorporating the brine slurry (RSTS) into a ceramic mass comprising inorganic materials.

 In addition, the present invention relates to the use of the ceramic coating composition in construction and to ceramic plates.

 BACKGROUND OF THE INVENTION

 The generation of industrial waste is one of the most serious problems facing modern society. Its inadequate disposition causes degradation of the environment, such as, for example, contamination of water sources and soil.

The generation of waste varies from country to country, socioeconomic status and from the results of many other practices. Once the solid waste is generated, it must be properly treated and processed at the source. Processing and handling may include sorting or segregation, washing and storage, to ensure recycling of parts of the waste. Throughout the world, solid waste management policies have been developed in order to make generators take responsibility for the objective of controlled disposal.

 Thus, the proper destination of residues represents one of the greatest challenges for the industries and the residue of the chlorine-soda industry, the brine mud (RSTS), is a classic example of this problem.

 The ceramic industry is one of the most prominent in recycling waste, both industrial and urban, due to its culminating volume of production that can enable the consumption of large quantities of waste, combined with the physical and chemical characteristics of its raw materials. raw materials and the particularities of ceramic processing.

 The process of reusing polluting industrial waste by incorporating ceramic materials for civil construction has gained great prominence in Brazil and worldwide. This process consists, for example, of incorporating the residue in a ceramic matrix used in the manufacture of materials such as solid bricks, ceramic blocks, tiles, floor and wall coverings, mortars and soil-cement bricks, among others.

 Thus, it is possible to incorporate industrial waste in a beneficial way to the ceramic mass, such as the addition of heavy ash, obtained from the burning of mineral coal; the inclusion of up to 5% of gem sludge in the manufacture of lining; flat glass residue; galvanic solid waste; that is, solid waste thus constituting an important alternative for environmental management.

The ceramic coating, as defined in NBR 13 816— 1997, is a material composed of clay and other inorganic raw materials generally used to coat floors and walls. The forming of the plates occurs by extrusion, pressing, or by other processes. Thus formed, the slabs are dried and burned at the sintering temperature, are non-combustible and are not affected by light.

 Usually, ceramic tiles for cladding have a square or rectangular shape, with varying dimensions. The base of the support has claws to help adhere to the surface where they will be laid and are called tardoz, which allow a better anchoring of the piece. The main purpose of applying the ceramic plate as a coating is to protect the substrate on which it is laid, providing for places where healthy characteristics are applied due to the impermeability of its enamel.

 A study by Freitas et al. (Incorporation of petroleum coke into red ceramics, 2011) evaluated the effect of incorporation of petroleum coke on the physical and mechanical properties of red ceramics. Compositions were prepared with 1%, 2% and 4% by weight of petroleum coke incorporated in a kaolinitic clay mass. The physical and mechanical properties determined were: flexural stress and water absorption. The microstructure of the fired ceramics was evaluated by optical microscopy. The results showed that the petroleum coke residue can contribute significantly to the reduction of energy consumption during the burning stage. However, incorporations must be carried out in quantities of around 1% by weight, in order not to impair the water absorption of the ceramic.

 The study by Rebmann et al. (Effect of the addition of basalt filler in red ceramic mass, 2001) showed that with the incorporation of 30% of load, from the crushing of the basalt to obtain crushed stone, the characteristics of the ceramic products were hardly changed, showing a great filling material for ceramic materials.

The study by Babisk et al. (Incorporation of quartzite residue in red ceramic, 2012) characterized and evaluated the effects of incorporation of quartzite residue in red ceramic. Incorporations of up to 40% by weight of ceramic mass residue and the specimens were burned at 800 ° C. The incorporation of quartzite residue in red ceramics was shown to be viable through this study, giving an environmentally correct destination to the residues that pollute and that in lower incorporation values maintain the technological properties of the pure ceramic mass, or even with higher incorporation values have properties within limits established by standards.

 The difficulties and advantages of incorporating oily residue from water and oil separators in petroleum activity in ceramic production are also known. According to Alves and Holanda (Recycling oily sludge through incorporation in ceramic sealing blocks, 2005), the most suitable content for incorporating oily sludge to manufacture ceramic blocks is in the range of 10 to 20% by weight, where their characteristics are maximized, such as mechanical resistance and water absorption, besides presenting chemical stability proven by the results of the leaching and solubilization analyzes.

 The feasibility of adding waste from granite, diabase and riodacite quarries has also been evaluated, in which the granite presented the best performance and the best combination of the achieved parameters was with the incorporation of 10% granite waste, according to Krindges study (Evaluation of the incorporation of rock powders and the temperature of synthesis in the performance and microstructure of red ceramics, 2009).

The incorporation of residues of galvanic solids in the structural red ceramic mass is an excellent alternative for the inertization of this type of waste. The addition of up to 2% of the washed waste showed that the technical properties were not alternated, according to the study by Balaton et al. (Incorporation of galvanic solid residues in red ceramic masses, 2002).

 The productive process of the “potteries” generates waste, in which the final product breaks and the ashes of the combustion process stand out. Breaks are waste resulting from the loss of the finished product after burning which can only be reused as a raw material after undergoing a grinding process, classifying it as an inert waste. The ashes obtained from the combustion of firewood predominantly from eucalyptus, also classified as an inert residue, is especially rich in calcium, being composed of calcium carbonate, with spherical and porous particle clusters and with an average size of 0.15 mm. The study by Borlini et al. (Ash from firewood for application in red ceramics part I: characteristics of ash. Cerâmica, 2005) pointed out that ash can act as a flux and can contribute to improve the burning properties through the reduction of porosity by the formation of liquid phase.

 Lopes (Study of the feasibility of adding smoke dust residues to the ceramic mass, 2005), in turn, added smoke dust residue and smoke dust ash to three samples of clayey soils from hill deposits and the results obtained showed the feasibility of incorporating both the smoke dust residue and the smoke dust ash.

 According to the study by Oliveira et al. (Characterization of waste (sludge) from a water treatment plant with a view to its use in red ceramics, 2004), the waste from the Water Treatment Plant (ETA) in the Campos dos Goytacazes-RJ region consists of a material with great potential for use in the red ceramic industry. This residue can be considered as a natural clay mass formulation.

For Menezes et al. (The state of the art on the use of waste as an alternative ceramic raw material, 2002), the ceramic industry has high capacity for absorbing waste, whether industrial or urban, due to its volume of production, as well as having a prominent position in the recycling of materials due to its ability to neutralize and stabilize various toxic waste.

 There is also the possibility of using welding slag residue generated by companies in the metalworking sector as a low-cost alternative raw material for the manufacture of ceramic products for civil construction such as multiple-use mortar and red ceramic (solid bricks and ceramic blocks).

 According to Viana et al. (Influence of the incorporation of welding flux slag residue on the technological properties of multiple use mortar and red ceramic for civil construction, 2010), the multiple use mortar incorporated with welding flux slag residue, when compared to traditional mortar obtained with natural sand, it presented better behavior in terms of physical-mechanical properties (consistency, density in the fresh state, content of incorporated air and mechanical resistance).

 The study by Esposito et al. (The use of Nepheline-Syentie via Bary mix for porcellaim stoneware tiles, 2005) investigated the use of nepheline syenite as a melting agent in a porcelain tile composition. The influence of nepheline syenite on the microstructure and mechanical properties of the sintered samples was evaluated. Starting from a standard composition, potassium feldspar was replaced by 5, 10 and 15.6% by weight of nepheline syenite. Nepheline syenite strongly favors sintering behavior, causing a significant reduction in the time required to reach a water absorption value of less than 0.5%.

However, the main technical problems when incorporating different residues in ceramic plates are energy costs of the processes due to the high melting temperature required to obtain the ceramic plate and the limited amount of residue added, in addition to the formation of plates taking into account the required flexural rupture modulus values.

 In view of the previous studies already carried out and of the possible associated technical problems, the Applicant surprisingly found that the reuse of the chlor-soda industry residue, the so-called brine slurry (RSTS), in ceramic coating plates (SPRC) is a way to provide a noble, advantageous and environmentally friendly destination for this type of waste. The incorporation of the brine slurry increases the fusibility at higher temperatures, and significantly increases the mechanical strength of the final material obtained.

 Additionally, the incorporation of a waste in a product needs to satisfy three criteria to be possible:

 Environmental Criterion, whose incorporation process and the products incorporated should not be as or more polluting than the original waste;

 Technical Criterion, in which the incorporation process and the properties of the incorporated product must not be impaired beyond a tolerable value;

 Economic, whose cost of incorporation should not compromise the marketing of the products incorporated.

Thus, the gradual incorporation of brine sludge in ceramic materials for coatings proved to be a viable solution that makes it possible to properly dispose of the waste, in addition to not requiring sophisticated and robust production, nor the acquisition of equipment, with its realization and simple logistics. Therefore, these three criteria are met. From an environmental point of view, the disposal of waste is solved; technically, there are no changes in the production process; economically, the incorporation of RSTS does not increase the final cost of the plates, in addition to the plate requiring the same tests already required by technical standards.

 SUMMARY OF THE INVENTION

 The present invention describes a coating composition for ceramic coating comprising a mixture of inorganic materials and a solid chemical residue called brine slurry (RSTS).

 The present invention also relates to a method of obtaining a base mass for ceramic coating that comprises the following steps:

 - Collection of a solid chemical residue, where the solid chemical residue is a brine slurry;

 - Preparation of brine sludge by drying in a range of 95 ° C to 135 ° C and grinding;

 - Incorporation of 0.5% to 10.0% by weight of brine mud in a ceramic mass comprising inorganic materials and, subsequently, homogenization between the ceramic mass and the brine mud, thus obtaining a homogeneous ceramic coating composition; where the percentage is based on the total weight of the composition obtained;

 - Humidification of the homogeneous composition by adding 1.0% to 15%, more preferably 8.0% by weight, of water, based on the total weight of the humidified homogeneous composition;

 - Total or partial drying of the humidified homogeneous composition, obtaining a homogeneous dry composition in granulated form or with low moisture content;

- Pressing the homogeneous composition dry or with low moisture content to obtain a base mass for ceramic coating with compaction pressure in the range between 180 and 260Kgf / cm2; and - Heat treatment of the base mass for ceramic coating through a process of sintering and final drying, using a temperature in the range of 800 ° C to 1650 ° C for a period of time from 20 to 75 minutes and cooling to temperatures in the range 100 ° C to 350 ° C, preferably in the range of 150 ° C to 250 ° C.

 In addition, the present invention describes the use of the ceramic coating composition in civil construction and ceramic plates comprising the composition.

 BRIEF DESCRIPTION OF THE FIGURES

 The detailed description presented below makes reference to the attached figures, which:

 figure 1 represents the side view of the ceramic tiles;

 figure 2 represents the top view of the ceramic tiles;

 - figure 3 represents the flowchart of the process for obtaining the base mass for ceramic coating with the incorporation of brine mud;

 figure 4 represents an X-ray diffractogram of the brine mud sample;

 - figure 5 represents the gresification curves of the masses for water absorption between 6.0% and 10% (Bllb typology);

 - figure 6 represents the gresification curves of the masses for water absorption between 0% and 0.5% (typology Bla);

 - figure 7 represents the digital image of the trend towards the formation of a black heart for water absorption between 6.0% and 10% (typology BIIb); and

- figure 8 represents the digital image of the trend towards the formation of a black heart for water absorption between 0% and 0.5% (typology Bla). DETAILED DESCRIPTION OF THE INVENTION

 The present invention relates to a ceramic coating composition comprising a mixture of inorganic materials and a solid chemical residue called brine slurry (RSTS). The composition of the present invention comprises brine slurry in a content of 0.5 to 10% by weight, based on the weight of the total composition. In a preferred embodiment, the composition comprises brine slurry in a content between 1.0 to 6.0% by weight, preferably between 1.5% to 4.0%, and more preferably between 2.0 to 4.0 .

 Brine sludge (RSTS) is a solid chemical residue resulting from the brine treatment that precedes the sodium chloride (NaCl) electrolysis process in the chlorine soda industry. The chemical composition of this solid residue comprises sodium oxide (Na20), calcium oxide (CaO) and magnesium oxide (MgO). In addition, the brine slurry referred to in the present invention comprises, in its mineralogical composition, sodium chloride, calcium carbonate (in the form of calcite) and magnesium oxide.

 In an embodiment of the present invention, the mixture of inorganic materials comprises clay. Preferably, the mixture of inorganic materials comprises clay and claystone. In the context of the present invention, clay comprises siltstones and varvites.

 In an alternative embodiment, the mixture of inorganic materials can also additionally comprise one or more inorganic raw materials selected from limestone, quartz, feldspar, feldspar sands, kaolin and phyllite.

 In one embodiment of the present invention, the brine slurry has high loss to fire (between 20% to 40% by weight, in relation to the total weight of the solid chemical residue).

The present invention also relates to a method of obtaining of a base mass for ceramic coating. In the context of the present invention, base mass means the support of ceramic tiles in contact with the surface where it is applied.

 More precisely, the method of obtaining the base mass for ceramic tiles according to the present invention comprises the following steps:

 - Collection of a solid chemical residue, where the solid chemical residue is a brine slurry;

 - Preparation of brine sludge by drying in a range of 95 ° C to 135 ° C and grinding;

 - Incorporation of 0.5% to 10.0% by weight of brine mud in a ceramic mass comprising inorganic materials and, subsequently, homogenization between the ceramic mass and the brine mud, thus obtaining a homogeneous ceramic coating composition; where the percentage is based on the total weight of the composition obtained;

 - Humidification of the homogeneous composition by adding 1.0% to 15%, more preferably 8.0% by weight, of water, based on the total weight of the humidified homogeneous composition;

 - Total or partial drying of the humidified homogeneous composition, obtaining a homogeneous dry composition in granulated form or with low moisture content;

 - Pressing the homogeneous composition dry or with low moisture content to obtain a base mass for ceramic coating with compaction pressure in the range between 180 and 260Kgf / cm2; and

- Heat treatment of the base mass for ceramic coating through a process of sintering and final drying, using a temperature in the range of 800 ° C to 1650 ° C for a period of time from 20 to 75 minutes and cooling to temperatures in the range 100 ° C to 350 ° C, preferably in the range 150 ° C to 250 ° C.

 In the brine slurry preparation step, the grinding can take place until complete passage in a mesh of 177 pm (80 Mesh).

 In a preferred embodiment, the brine slurry is incorporated into the ceramic mass in a content between 1.0% to 6.0%, more preferably between 1.5% to 4.0%, and more preferably between 2.0% to 4.0%.

 In the step of incorporating the brine sludge into the ceramic mass, the ceramic mass preferably comprises clay. In a preferred embodiment, the ceramic mass comprises clay and clay. In addition, the ceramic mass can also comprise other inorganic raw materials selected from limestone, quartz, feldspar, feldspar sands, kaolin and phyllite.

 The homogeneous compositions obtained in the method of the present invention are dry or semi-dry, in granulated form, to obtain parts by pressing. Preferably, homogeneous dry and granular compositions are used, or partially dry, that is, with low moisture content.

 In the context of the present invention, low moisture content means a reduction in moisture content by at least 50% by weight, based on the initial water content of the humidified homogeneous composition. Preferably, in the drying step the residual moisture evaporates from the humidified homogeneous composition, leaving a water content in the range of 3.0% to 9.0% by weight of water, based on the homogeneous dry composition. Thus, in the drying step, an increase in the mechanical strength of the PRC is observed simultaneously due to the increase in packaging and attraction between the particles.

There are several types of press that can be used in the pressing stage to obtain the base mass for ceramic coating, such as: friction, hydraulic and hydraulic-mechanical, which can be single or double acting and also have vibration, vacuum and heating devices.

 After pressing, the base mass is subjected to heat treatment at elevated temperatures (sintering and final drying process), in continuous or intermittent furnaces that operate in three phases:

 The. Heating from room temperature to the desired temperature;

 B. Plateau for a certain time at the specified temperature; ç. Cooling down to temperatures in the range 100 ° C to 350 ° C, preferably in the range 150 ° C to 250 ° C.

 Thus, the base mass for ceramic coating undergoes a heat treatment, in which it is burned, that is, subjected to certain temperatures in the range of 800 ° C to 1650 ° C, preferably in the range of 1100 ° C to 1300 ° C, in cycles with durations ranging from 20 to 75 minutes. In one embodiment of the present invention, the sintering process cycles can last from 20 to 70 minutes, or even from 20 to 60 minutes, depending on the nature of the ceramic mass and the desired dimensions.

 During this heat treatment, a series of transformations takes place depending on the components present in the base mass for ceramic coating, such as: loss of mass, development of new crystalline phases, formation of glass phase and the welding of grains. Therefore, depending on the heat treatment to be used (heating temperature, duration and cooling temperature) and the characteristics of the different raw materials, products are obtained for the most diverse applications.

The ceramic coating composition of the present invention can be used for civil construction, such as, for example, for covering floors and walls in general. In one embodiment of the present invention, floors and walls must meet the standards NBR 13,816, NBR 13,817 and NBR 13,818, which represent the three sets of standards for ceramic tiles, according to ABNT (Brazilian Association of Technical Standards).

 The standard NBR 13,816 defines the terminology of ceramic tiles for cladding, defining that they are materials composed of clay and other inorganic raw materials, generally used to coat floors and walls, being shaped by extraction or pressing, and can also be shaped by other processes.

 The NBR 13,817 standard classifies ceramic tiles for coverings, aiming to promote the correct specification for use. The plates can be classified according to the following criteria: 1) Enamelled and non-enamelled; 2) Manufacturing method (pressed, extruded, among others); 3); Water absorption groups; 4) Surface abrasion resistance class; 5) Class of resistance to staining; 6) Class of resistance to attack by chemical agents, according to different levels of concentration; and 7) Superficial appearance or visual analysis.

 The NBR 13,818 standard defines the specification and test methods of the plates, fixing the characteristics required for manufacturing, marking, declarations in catalogs, receiving, inspection, sampling, complementary optional tests, test methods and acceptance of ceramic plates for coating.

 Thus, the present invention is also related to ceramic plates comprising a ceramic coating composition containing a mixture of inorganic materials and brine slurry.

In a preferred embodiment of the present invention, ceramic tiles for cladding are classified into two types, according to NBR 13.817: the semi-porous coating (Bllb) and the porcelain tile (Bla), which are products characterized by excellent technical performance, such as high density, abrasion and stain resistance and surface hardness. This classification is related to one of the fundamental parameters for the ceramic coating: the absorption of water, which, in turn, is strictly related to the porosity and permeability of the ceramic piece and other properties of the product.

 The mechanical resistance of the product, for example, is greater, the lower the water absorption. Thus, the Brazilian standard defines that in a semi-porous coating (Bllb), the water absorption is in the range between 6.0% to 10.0% by weight, based on the total weight of the ceramic tile. Porcelain tiles (Bla) are defined as having a water absorption between 0 to 0.5% by weight, based on the total weight of the ceramic tile.

 Thus, in a modality of the present invention, the thermal treatment of the base mass for ceramic coating is carried out in order to reach the levels of water absorption (Abs) for products of the Bllb and Bla typology.

 The following description will start from preferred embodiments of the invention. As will be apparent to any person skilled in the art, the invention is not limited to these particular embodiments.

 EXAMPLES

Characterization of the industrial waste used

 First, the industrial waste used (brine sludge) was characterized to assess whether there would be a possible interference in the characteristics of the base mass for the ceramic coating produced.

The analysis of the chemical and mineralogical composition of the brine slurry is presented in Tables 1 and 2 and in Figure 4. Table 1. Chemical composition of the brine mud sample by weight, based on the total weight of the mud obtained.

 Oxides _ Percentage (%)

 29.71

 Fe203 0.32

 T02 0.02

 CaO 17.81

 MgO 12.63

 Na20 23.70

 P205 10.55

This chemical composition represents the percentage of elements present in the brine mud sample, given the need to know them, considering that the composition integrates the ceramic mass and can result in physical-chemical transformations during the firing process.

 Thus, it can be seen in Table 1 that the brine slurry is chemically composed mainly of sodium oxide (Na20), calcium oxide (CaO) and magnesium oxide (MgO), in addition to having high loss to fire (29.71 %). From a mineralogical point of view, it can be seen from Table 2 and Figure 4 that the brine slurry is mainly composed of sodium chloride, with a high calcite content and significant magnesium oxide content.

 The result of the structural analysis technique presented in Figure 4 allowed to identify the different materials by means of X-ray diffraction, and the results are shown in Table 2.

Table 2. Mineralogical composition of the RSTS sample.

 Crystalline phases Estimated content (%)

 Calcite 32.00

 Magnesium hydroxide 18.00

 Sodium chloride 45.00

 Other 5.00

Based on these initial results, the brine sludge it was incorporated into an industrial standard mass for later evaluation and characterization of the base mass for ceramic coating obtained.

 Characterization of the standard mass used

 The analysis of the chemical composition of the standard mass is shown in Table 3.

 Table 3. Chemical composition of the standard mass by weight.

 Compounds Percentage (%)

 Si02 66.73

 A1203 14.9

 Fe203 5.40

 CaO 1.97

 K20 2.70

 MgO 1.88

 Na20 1.07

 P205 0.13

 Ti02 0.80

 Loss to Fire_ 4.39

 Table 3 shows the results of the quantitative chemical analysis of the ceramic mass used, showing in percentage of the weight of the oxide compounds as well as the loss to fire. The dough has a typical composition of clay raw material and lower percentages of Fe, Ca, K, Mg, P, Na and Ti.

 Thus, it is noted that the composition of the masses shows a higher concentration of silicon oxide, Si02, followed by aluminum oxide,

A1203, a component that makes ceramic materials refractory. It is also observed that the amount of iron is compatible with the ocher tone of the dough.

 The first two members of Table 3 represent the purest form of the clay with nine oxides that integrate it, together with the percentage of Loss to Fire (PF), determine the clay's characteristic.

The mineralogical analysis of the mass showed six different minerals, in favorable proportions, which generated crystalline phases suitable for the production of the base mass for coating of the present invention. The predominant mineral clay is quartz, being an integral part of the mass that fundamentally it has the function of adjusting the coefficient of thermal expansion and, to a lesser extent, kaolinite, albite, microcline, muscovite and tremolite are present.

 Incorporation of industrial waste into a ceramic mass and molding of parts

 Then, standard parts were molded, and the satisfactory results were identified in the parts with 2.0%, 4.0% and 6.0% of incorporation of the brine mud into a ceramic mass, according to the comparative data shown in Table 4 .

Table 4: Incorporation of brine sludge (RSTS) into the industrial standard mass.

To validate the base mass for the ceramic coating obtained, ten specimens were evaluated before firing using the following parameters:

 - Apparent density in green: obtained with specimens dried at 110 ° C, determining the mass on an analytical balance (uncertainty of 0.01 g) and the apparent volume by geometric method using a digital caliper;

 - Extraction expansion: considering the dimensional variation of the specimen length after extraction of the press in relation to the length of the die. Measurements were performed with a digital caliper (0.001 cm uncertainty):

 Values obtained through the Equation.

Li = L ₀ + RE RLs RLq Equation 1 Where:

 Li = final length;

L ₀ = mold length;

 RE = expansion in the extraction of the mold;

 RLs = linear drying retraction;

 RLq = linear firing retraction.

 - Linear drying retraction: dimensional variation in the direction of the length of the wet specimen (after extraction of the press) and after drying:

 Values obtained through Equation 2.

Equation 2

 Where:

RL _{0 / o} = linear retraction;

l ₀ = initial length;

 l = final length.

Equação 3- Flexural rupture module: determined with wet specimens (immediately after extraction of the press), and dried at 110 ° C through the flexometer test at three points in a fleximeter (Equation 3):

Equation 3

In which:

 P = breaking load;

 L = distance between the base masses;

 b = width of the sample;

 h = thickness of the sample.

- Apparent density after heat treatment: obtained with the sintered specimens, determining the mass in an analytical balance (0.01 g uncertainty) and the apparent volume by geometric method using a digital caliper; Density can be measured using two methods:

1) The apparent density values, dry or after burning, are obtained through Equation 1:

M ₀ . dH _g

 D ap-Hg

 i Equation 1

Where:

D _ap-Hg = Apparent density found using mercury;

M ₀ = Mass of the specimen before submersion;

M ₁ = Mass of the specimen after submersion;

dH _g = Mercury density.

2) Or by the experimental method, through equation 5:

Equation 2

 Where:

D _ap = apparent density of the raw base mass;

Dp _ara fi _na ⁼ Paraffin density;

D _{HZ O} = Water density;

 m = Mass of the base mass;

mParaffin ⁼ Mass of the paraffin that waterproofed the base mass; M '= Mass of water displaced by the raw ceramic base mass.

Table 5 shows the results of the characterization of the specimens before burning, after pressing, prepared with each of the compositions in Table 4. Table 5. Characteristics of the specimens after compaction.

 Table 5 shows the behavior of the tested masses, with an improvement in the flexural rupture module in the incorporated parts, which varied from 11 to 13 Kg.f.cm-2.

 The specimens obtained after firing were characterized according to the following characteristics:

 - Water absorption: assessed by mass percentage gain after saturation of the pores with boiling water for two hours and measured on an analytical balance with an accuracy of 0.001 g;

 - Linear firing retraction: measurement of the dimensional variation in the direction of the length of the dry specimen and after firing, using a digital caliper with a precision of 0.01 mm;

 - Loss to fire: considering the percentage loss in mass of the dry specimen in relation to the burned one and evaluated in an analytical balance; and

 - Flexural rupture module: determined with the wet specimens (immediately after extraction of the press) and dried at 110 ° C through the flexion test at three points in a fleximeter.

 Table 6 shows the dimensions of the Bllb and Bla pieces (based on the desired water absorption) obtained.

Table 6. Measurements of ceramic pieces obtained Measurement chart

Tables 7 and 8 show the characteristics of the pieces obtained as a function of the firing temperature and water absorption between 6.0% and 10.0% by weight (Bllb typology).

Table 7. Burning temperature for water absorption between

 Thus, it was possible to observe that the flexural rupture module was expanded in the three incorporated parts.

 Soon after, the results of the characterization for absorption less than or equal to 0.5% - Bla typology (Table 6) were evaluated.

Table 8. Burning temperature for water absorption <0.5%

Table 7 presents six characteristics and it can be highlighted that the flexural rupture module showed growth, in particular, for the incorporation of 2% of RSTS. The results of water absorption and linear firing retraction allow the construction of the gresification curve. The gresification curve is the simultaneous graphical representation of variations in water absorption and linear shrinkage of the part with the firing temperature. In addition, the gresification curve allows to evaluate the mass tolerance to temperature variations and processing conditions, and therefore, it can be of great use as a quality control instrument.

 Figure 5 shows the samples' gresification curves for water absorption between 6.0% and 10% by weight, which were built using the water absorption characteristics and linear burning retraction, as a function of temperature.

According to the standard, as water absorption evolves, linear shrinkage also decreases. It can be seen that for the RSTS-2 sample, the behavior of water absorption is consistent with the pattern, however the corresponding linear shrinkage curve evolves, thus characterizing the action of the mud on the part. The same behavior is repeated in the other proportions of mud (RSTS-4 and RSTS-6). It was possible to observe that the flexural rupture module was expanded in the three incorporated parts. On the other hand, the RSTS-6 formulation, although it starts the gresification curve with higher water absorption in relation to the standard sample, this characteristic decreases rapidly with increasing temperature and, in this case, the temperature for water absorption close to the value obtained in the standard mass is smaller, indicating a pronounced increase in fusibility at higher temperatures.

 Figure 6 shows the samples' gresification curves for water absorption <0.5% by weight.

 Another parameter analyzed is the tendency to form a black heart, where specimens were pressed in a metallic mold measuring 60 mm x 20 mm and 10 mm thick. They were waterproofed from their surface with flux enamel so that, after drying at 110 ° C and burning in a rapid cycle of 15 minutes, the evaluation of the tendency to black heart formation was carried out. This assessment is made visually from the cross section of the broken specimens after burning.

 As shown in figure 7, the black heart consists of a dark region (usually gray) that extends, parallel to the face and close to half the thickness, along the piece. The dark region usually disappears near the edges of the part. Some of the main damaging consequences of the presence of the black heart, which justify efforts to avoid it, are: swelling of the parts, pyroplastic deformations, in addition to the deterioration of technical and / or aesthetic characteristics.

 The cross-sectional images of the specimens after the black heart formation tendency test are shown in figures 7 and 8 for water absorptions of 6 to 10% and 0 to 0.5%, respectively.

In figure 7, it is visually verified that the darkened image, in the center of the part, of the samples incorporated with RSTS, RSTS-2 (2%), RSTS-4 (4%) and RSTS-6 (6%), behave in a similar way to the standard. In figure 8, it can be seen that the RSTS-2 sample showed a lower rate of black heart formation.

 The present invention also found that the addition of brine sludge residue (RSTS) positively influenced the material's technological properties, even before burning, after drying, as observed in the Flexural Break Module (MRF), when comparing green parts with dry parts.

 The incorporation of RSTS waste influences the technological properties of sintering. The percentage of linear shrinkage increases with increasing sintering temperature as well as with the addition of this residue. Water absorption has the opposite effect. The apparent porosity follows the same behavior as water absorption and the volume of the pores decreases with increasing temperature. For the apparent density, the effect of temperature was to promote a greater densification of the ceramic pieces, mainly at higher temperatures. The flexural tensile strength increased with the sintering temperature and with the addition of RSTS, the incorporation of RSTS-6 being the result that presented the highest MRF values, at the different temperatures used.

 In all levels tested, the tailings contributed to the mechanical resistance of the burned bodies, considering the products obtained with water absorption within the specification of the Bllb class. From a temperature of approximately 1,125 ° C, small increases in temperature promoted great decreases in water absorption. For RSTS-6 material, this effect is noted from 1,115 ° C. This behavior was even more accentuated in tests carried out at higher temperatures, enabling normative validation for porcelain tiles.

As noted, the incorporation of industrial waste in the mass ceramics favored an important reduction in the firing temperature of the product. This increase in mechanical resistance is due to the formation of stronger chemical bonds through the interaction of carbonates and hydroxides in the mass composition.

 Regarding the tendency of black heart formation, in general, there were no variations between the behavior of the formulated masses in relation to the standard ceramic mass.

 Thus, in ceramic tiles classified as semi-porous (class Bllb), the brine sludge could contribute to the increase of the mechanical resistance of the pieces before and after firing even in small proportions, that is, in contents below 5.0% , in which the ideal percentage is 6.0% by weight of waste. Throughout the heat treatment of burning, there was a need for a small increase in temperature for the melt of the tailings to manifest.

 For ceramic tiles classified as porcelain tiles (class Bla), three benefits are observed: the improvement of mechanical properties before firing; the possibility of industrial waste being used as an additive capable of improving the fusibility of the mass; and the reduction of the cost of the execution process, since lower temperatures are necessary to reach the required water absorption index.

 Thus, it was possible to prove that the levels of addition of brine mud imply specific gains for the mechanical resistance of the burnt tasting glasses.

Claims

 1. Composition for ceramic coating, characterized by comprising a mixture of inorganic materials and a solid chemical residue, in which the solid chemical residue is a brine slurry.  Composition according to claim 1, characterized in that the composition comprises brine slurry in a content of 0.5 to 10% by weight, based on the weight of the total composition.  Composition according to claim 1 or 2, characterized in that the mixture of inorganic materials comprises clay.  4. Composition according to claim 3, characterized by the fact that it comprises claystones.  Composition according to any one of claims 1 to 4, characterized by the fact that the brine slurry is a solid chemical residue resulting from the brine treatment that precedes the sodium chloride electrolysis process in the chlorine soda industry.  Composition according to any one of Claims 1 to 5, characterized in that the chemical composition of the brine sludge comprises sodium oxide (Na20), calcium oxide (CaO) and magnesium oxide (MgO).  Composition according to any one of claims 1 to 6, characterized in that the mineralogical composition of the brine sludge comprises sodium chloride, calcium carbonate (in the form of calcite) and magnesium oxide. 8. Composition according to any one of claims 3 to 7, characterized by the fact that the mixture of inorganic materials also comprises one or more inorganic raw materials selected from limestone, quartz, feldspar, feldspar sands, kaolin and phyllite. 9. Method of obtaining a base mass for ceramic coating, characterized by the fact that it comprises the following steps:  - Collection of a solid chemical residue, where the solid chemical residue is a brine slurry;  - Preparation of brine sludge by drying in a range of 95 ° C to 135 ° C and grinding;  - Incorporation of 0.5% to 10.0% by weight of brine mud in a ceramic mass comprising inorganic materials and, subsequently, homogenization between the ceramic mass and the brine mud, thus obtaining a homogeneous ceramic coating composition; where the percentage is based on the total weight of the composition obtained;  - Humidification of the homogeneous composition by adding 1.0% to 15%, more preferably 8.0% by weight, of water, based on the total weight of the humidified homogeneous composition;  - Total or partial drying of the humidified homogeneous composition, obtaining a homogeneous dry composition in granulated form or with low moisture content;  - Pressing the homogeneous composition dry or with low moisture content to obtain a base mass for ceramic coating, with compaction pressure in the range between 180 and 260Kgf / cm2; and  - Heat treatment of the base mass for ceramic coating through a process of sintering and final drying, using a temperature in the range of 800 ° C to 1650 ° C for a period of time from 20 to 75 minutes and cooling to temperatures in the range 100 ° C to 350 ° C, preferably in the range of 150 ° C to 250 ° C. 10. Method according to claim 9, characterized by the fact that the grinding step occurs until complete passage in a mesh aperture 177 mhi (80 Mesh).  Method according to claim 9 or 10, characterized in that, in the step of incorporating the brine sludge into the ceramic mass, the ceramic mass comprises clay.  12. Method according to claim 11, characterized by the fact that the ceramic mass comprises claystones.  13. Method according to claim 11 or 12, characterized by the fact that the ceramic mass also comprises one or more inorganic raw materials selected from limestone, quartz, feldspar, feldspar sands, kaolin and phyllite.  Method according to any one of claims 9 to 13, characterized in that the brine slurry is incorporated into the ceramic mass in a content between 1.0% to 6.0%, more preferably between 1.5% to 4.0%, and more preferably between 2.0% to 4.0%.  Method according to any one of claims 9 to 14, characterized in that in the heat treatment the cycles of the sintering process last from 20 to 70 minutes, or from 20 to 60 minutes.  16. Use of the ceramic coating composition as defined in claim 1, characterized by the fact that it is in civil construction.  17. Use of the ceramic coating composition according to claim 16, characterized by the fact that it is used to coat floors and walls.  18. Ceramic plate characterized by the fact that it comprises the ceramic coating composition as defined in claim 1.  19. Ceramic plate according to claim 17, characterized in that it is a semi-porous type coating with a water absorption in the range of 6.0% to 10.0% by weight, based on the total weight of the plate pottery. 20. Ceramic plate according to claim 17, characterized because it is a porcelain-like coating with water absorption in the range of 0% to 0.5% by weight, based on the total weight of the ceramic plate.