How chalk is made. Chalk Rock, description, properties, deposits and photos

Many people associate chalk with school, or rather with a school board and a lot of words and formulas. But few know that these soft white limestone sticks are capable of so much more. Now we will tell you about alternative methods of using ordinary chalk that will definitely come in handy for you!

How to use chalk

1. Bleach collars

Rub the stain thoroughly with white chalk. Leave the chalk on for 10 minutes and then launder as usual. The chalk will absorb dirt and help whiten the collars of your shirts.

2. Remove grease stains

A fresh stain from your favorite sandwich will quickly disappear if rubbed with chalk and left for 10 minutes. Wipe off excess chalk before loading into the washing machine.

3. Remove stains from suede shoes

Grind the chalk and sprinkle it on the greasy stain. Leave on for a few hours or overnight. The stain will be gone in the morning!

4. Prevention of unpleasant odors in the laundry basket

Place a few pieces of chalk in the bottom of the laundry basket. The chalk will absorb moisture from the clothes, preventing mold. It is important to change the chalk to a new one at least once a month.

5. Shine your cutlery

Put a piece of chalk in the place where you store silverware. It will absorb moisture and retain the shine of the silver.

6. Jewelry won't tarnish anymore

A piece of chalk in the box will also prevent your jewelry from tarnishing. The chalk will absorb the sulfur compounds inside the box and the decorations will not blacken.

7. Wardrobe odor prevention

Pieces of chalk in the closet will prevent the mustiness that often forms in closed cabinets.

8. Furniture rearrangement

Chalk can be used to create a tentative version of furniture rearrangement. You can draw a diagram on the floor and look from the side before you start moving things around.

9. Rust protection

Chalk absorbs moisture, so a handful of chalk in your toolbox will help prevent rust.

10. Hide stains on the ceiling

You can temporarily hide smudges or traces of dirt on the ceiling with white chalk.

11. Ant Repellent

For some reason, ants don't like to cross chalk lines. Draw a line at doorways, on window sills, in a word, everywhere from where ants come to your house.

12. Nail whitening

Rub the brush with white chalk, then rub it under the tips of your nails. The bristles will remove dirt, and the white chalk will make the inner surface of the nails bright, clean and well-groomed.

Dry chalk has a modulus of elasticity from 3000 MPa (for loose chalk) to 10000 MPa (for dense chalk) and behaves like an elastic body. The angle of internal friction of the chalk is equal, the grip under conditions of all-round compression reaches 700-800.

When moistened, the strength of chalk begins to decrease already at a moisture content of 1-2%, and at a moisture content of 20-30%, the compressive strength increases by 2-3 times, while plastic properties appear. The manifestation of the viscous-plastic properties of natural chalk with an increase in its moisture content leads to serious complications in the technology during its processing. From this, chalk sticks to vehicle elements (excavator bucket, dump truck body, feeder, conveyor belt). Sticking of roller gear crushers is observed. This leads in some cases to the failure of the extraction of chalk from the lower watered horizons, although the quality of the chalk of the lower horizons refers to high-quality chalk.

Natural chalk practically does not have frost resistance; after several cycles of freezing and thawing, it breaks up into separate pieces 1-3 mm in size. This phenomenon is in some cases a positive factor. So, for example, when using chalk as an ameliorant for soil deoxidation, it is not necessary to grind it to a particle size of - 0.25 mm (limestone flour), but crushed chalk can be added to the soil up to - 10 mm. When freezing and thawing with annual plowing of the soil, the pieces of chalk are destroyed and its soil neutralizing action is preserved for a long time.

As already noted, chalk consists mainly of two main parts - the carbonate part, soluble in hydrochloric and acetic acids (calcium, magnesium carbonates) and the non-carbonate part (clays, marls, quartz sand, metal oxides, etc.) which do not dissolve in these acids. The carbonate part of the chalk is 98-99% calcium carbonate. Small amounts of magnesium carbonates are present, which form crystals of magnesian calcite, dolomite, and siderite scattered in the groundmass of the chalk.

The most acceptable is the classification according to the content of carbonates and grades of chalk products.

Classification of chalk according to the content of carbonates and grades of products from it

The chemical characteristics of the chalk of some Russian deposits are given in Table 4. Initially, it was believed that chalk is a rock mass, which is the same throughout the deposit in terms of chemical composition and physical properties. However, during long-term operation of the deposit, and especially during the transition of the chalk enterprise to the production of higher quality chalk products, it was found that in different areas (horizons) chalk differs both in chemical composition and in physical and mechanical properties. In this regard, geological and technological mapping is carried out at some chalk deposits, in which areas of high-quality chalk are identified.

The chalk deposits of the Belgorod region are characterized by a low content of insoluble residue and a high content of carbonates. Table 1.5 shows the reserves and chemical composition of the largest fields in the Belgorod region.

Calcium carbonate (chalk) is a widely used material in the modern world industry. The development of rubber and electrical, polymer, paintwork, and other industries requires an increase in the production of high-quality fillers, which primarily include chalk. The annual consumption of natural chalk in lump, crushed and crushed form in developed countries exceeds 150 million tons. Over 7.5 million tons of ground chalk are produced annually in the USA and Canada and more than 15 million tons in Europe.

Chalk as a widely available filler is becoming extremely important for many industries. A distinctive feature of this natural material is that it is easily mined and processed at relatively low cost. The extraction and processing of chalk does not cause serious environmental disturbances. Chalk reserves are practically unlimited in many European countries, countries of the former CIS and in Russia.

A powerful chalk belt stretches across the entire European continent, including the north of France, the southern part of England, Poland, passes through Ukraine, Russia and moves to Asia - Syria and the Libyan desert.

Chalk reserves are unevenly distributed over the territories: about 48 - 50% of the reserves of high-quality chalk with a high content of calcium and magnesium carbonate, a minimum content of harmful impurities are concentrated in Russia; about 32 - 33% in Ukraine and a little over 12% in Belarus. There are small deposits in Kazakhstan, Lithuania and Georgia. The total balance reserves of chalk in Russia are estimated at 3,300 million tons with unlimited probable reserves.

The Belgorod region has practically unlimited predictable chalk resources. In total, 29 chalk deposits with total reserves of 1000 million tons have been explored in the region. The largest chalk deposits are Lebedinskoye, Stoilenskoye and Logovskoye. At the same time, the Lebedinskoye and Stoilenskoye deposits account for 75% of the explored reserves of chalk in the Belgorod region. These two deposits are exploited for the extraction of iron ores, where chalk is the overburden.

Every year, over 15 million tons of chalk is mined and exported to dumps at the listed deposits, where it is irretrievably lost. Only a small part of it (about 5.0 million tons) is used for the production of cement and ground chalk. In addition to the traditional consumers of chalk, new consumers have emerged in recent years, such as the pulp and paper industry, where fine chalk has been used instead of kaolin. Chalk also began to be used to deoxidize acidic soils, it was proved that its activity is 30% higher than that of lime flour.

Chalk is a carbonate rock (a kind of limestone) almost completely composed of calcite (91-98.5%). Outwardly, it is a white, weakly cemented, fine-grained, dirty rock, called "white writing chalk." In the composition of chalk, three main uniform elements of the calcite composition are distinguished, both of biogenic and autogenous origin. Organic remains usually make up the bulk of the rock (up to 75%). In the main mass, they are represented by skeletal shells of planktonic algae-coccolithophores, as well as foraminifera (sometimes up to 40%). The size of skeletal remains is 5-10 microns. Variable, but sometimes significant value (10-90%) is powdered calcite with particles 0.5-2 microns in size. A smaller development belongs to larger (5-10% µm.) well-limited calcite crystals. There are shells of inocerams (in places up to 13-20%), remains of crinoids, sea urchins, and corals. In small quantities, usually up to 5, less often up to 10-12%, there are pelitomorphic non-carbonate impurities, mainly of terrigenous, less often of autogenous origin: quartz, feldspars, clay minerals (glauconite, kaolinite, hydromica, montmorillonite), opal, chalcedony, pyrite, etc. Flint concretions are found in places.

In the chalk strata, the development of large sustained cracks is observed - reservoir and vertical, filled with chalk flour. At the surface outcrops, the network of cracks is strongly concentrated. When chalk samples are impregnated with oil, hidden vein structures appear in them in the form of intertwining tiny cracks, as well as traces of numerous passages of worms - worms.

Chalk is a white sedimentary rock. It is insoluble in water and is of organic origin. From the article we learn where chalk is used, the physical and chemical properties of this rock.

Education

90 million years ago in Northern Europe, in the lower region of the great sea, silt accumulated. Protozoa (foraminifera) lived on marine debris. Their particles included calcite extracted from water. The Cretaceous group of the stratigraphic European division appeared during the period of the same name. From it formed in Kent and slopes in another part of the Strait of Dover. It was these remains that became the basis of the chalk. However, the rock mainly consists of formations of algae and finely dispersed compounds. Thus, the researchers conclude that the appearance of chalk is the merit of plants.

Rock structure

The remains of mollusks that accumulated in bottom sediments turned into chalk. The breed contains:

1. About 10% of skeletal debris. Among them are not only parts of protozoa, but also multicellular animals.
2. About 10% of foraminifera shells.
3. Up to 40% fragments of calcareous algae formations
4. Up to 50% crystalline fine calcite. Its size is so small that it is almost impossible to establish the biological identity of the elements that make it up.
5. Up to 3% insoluble minerals. They are mainly represented by silicates. Insoluble minerals are a kind of geological debris (fragments of various rocks and sand), which is brought into the chalk deposits by currents and winds.

Mollusk shells, concretions of other minerals, and skeletons of coelenterates are found quite rarely in the rock.

Description of the physical property of chalk - strength

Studies of the substance were carried out by many scientists. In the course of engineering and geological measures, it was revealed that it is a rigid semi-rocky rock. Its strength is largely determined by moisture. In the air-dry state, the compressive strength varies from 1000 to 45,000 kN/m 2 . dry rock - from 3 thousand MPa (for a loose state) to 10 thousand MPa (for a dense one). The value of the angle of internal friction is 24-30 degrees, with all-round compression, the adhesion reaches 700-800 kN/m 2 .

Humidity

When exposed to water, the physical properties of chalk begin to change. In particular, its strength is reduced. Changes occur already at 1-2% humidity. At 25-35%, the compressive strength increases by 2-3 times. Along with this, other physical properties of chalk appear. The rock becomes plastic. This manifestation significantly complicates the process of processing the substance. During this, the chalk begins to stick to the elements of the machines (on the excavator bucket, feeder, vehicle body). Often, the physical properties of chalk (viscosity and plasticity) do not allow mining from lower horizons, although here it is considered to be of high quality.

Frost resistance

After freezing-thawing, the chalk breaks up into particles 1-2 mm in size. In some cases, this is a useful property of the breed. For example, when it is used as an ameliorant during soil deoxidation, it is not necessary to grind the substance to 0.25 mm. Crushed rock up to 10 mm can be introduced into the soil. When freezing-thawing with plowing the soil, the pieces are destroyed by themselves. Thus, the neutralizing effect is maintained for a long time.

Chalk Properties: Chemistry

The rock mainly includes carbonate and non-carbonate parts. The first is soluble in acetic and hydrochloric acids. The non-carbonate part contains metal oxides, quartz sand, marls, clays, etc. Some of them are insoluble in these acids. The carbonate part contains 98-99% calcium carbonate. Crystalline particles of magnesian calcite, siderite and dolomite are formed by magnesium carbonates, which are included in chalk in small amounts. The composition and properties of the rock act as classification criteria.

Identification of quality deposits

Initially, it was believed that the mechanical and chemical properties of chalk are the same throughout the deposit. However, in practice, during the long-term exploitation of the region, especially after the transition of the mining and processing enterprise to the production of higher quality products, differences in these characteristics are revealed. Therefore, geological and technological mapping is carried out at some fields. Researchers, studying the chemical properties of chalk and its mechanical characteristics in different parts of the deposit, designate areas of accumulation of high-quality rock.

Industrial development

Large deposits of chalk are present in the Belgorod and Voronezh regions. Less quality substance is present in the Znamenskaya, Zaslonovskaya, Valuyskaya and other deposits. Relatively low rates of CaCO 3 (no more than 87%) are revealed at these deposits. In addition, various impurities are present in the rock. Therefore, high-quality products cannot be obtained at these deposits without deep enrichment. The physical properties of chalk on such deposits make it possible to use it in the manufacture of lime, as well as in land reclamation measures to deoxidize soils. The Voronezh deposits are attributed to the Turonian-Cognac age. Higher quality chalk is mined here. The properties and application of the rock obtained from these deposits have been studied for a long time. The product mined in the Voronezh region has a high CaCO 3 content (up to 98.5%). The proportion of non-carbonate impurities is less than 2%. Mining at the deposits, however, is hampered by the physical properties of the chalk. In particular, its high water saturation. The proportion of moisture in the rock is about 32%.

Promising deposits

Among the large deposits, it is worth noting Rossoshanskoye, Krupnennikovskoye, Buturlinskoye and Kopanishchenskoye. The chalk thickness of the latter is 16.5-85 m. The overburden is the soil-vegetative layer. Its thickness is about 1.8-2 m. The chalk layer is divided into two units along the vertical line. At the bottom there is up to 98% calcium carbonate, at the top it is slightly less - up to 96-97.5%.

Extremely homogeneous white chalk of the Turunian stage was found in the Buturlinskoye deposit. The thickness of the layer is 19.5-41 m. The overburden thickness reaches 9.5 m. It is represented by margels, vegetation layer, sandy-clayey formations and sandstones. The share of magnesium and calcium carbonates reaches 99.3%. At the same time, non-carbonate components are present in a relatively small amount.

Of great interest to industry are the Stoilenskoye and Lebedinskoye deposits. In these areas, chalk is mined as overburden and taken to dumps. The associated annual production is more than 15 million tons. About five of them are used in the national economic sectors. In particular, chalk is supplied to the Starooskol cement plant and some other small enterprises. Most of the mined rock is lost in the dumps.

Chalk, which is located in areas of iron ore deposits, is classified as high-quality in terms of silica and carbonate content. It can be used for industrial purposes without deep enrichment. It must be said that in the process of designing mining and processing enterprises specializing in iron ores, it is necessary to provide for technological lines for the incidentally extracted chalk or a place for its separate storage.

Production and consumption

The beneficial properties of chalk have been known for a long time. Initially, the breed was used in construction. Lime was made from it. Chalk powder acted as the basis for putty, fillers, paints and so on. At the end of the 19th century, private factories began to be organized at the White Mountain deposit. Lime and powder were produced from lumpy rock. In 1935, the Shebekinsky plant appeared, which was engaged in the production of products for industrial needs. Useful properties of chalk were in demand in the electrical, paint, polymer, rubber and other industries.

Along with the increase in the demand for products, the requirements for its quality increased. The enterprises that existed by 1990 could not provide the industry with the necessary raw materials. Private enterprises began to appear in the Belgorod region. Their large number was due to the huge volumes of rock deposits and the apparent simplicity of processing technologies. However, the primitive methods of extraction and subsequent processing used by private enterprises could not provide the required amount of quality products. Accordingly, many such factories closed. At the same time, large enterprises have modernized and reconstructed their equipment. The release of quality products was provided in the 90s by the Belgorod, Petropavlovsk, Shebekinsky plants.

Production of quality brands

The key requirements for chalk products, in addition to the proportion of carbonates, include fineness - fineness of grinding. It is expressed as a residue on sieves of a certain size or as a percentage of particles of a given size (for example, 90% of particles with a size of 2 microns).

The emergence of new production lines for the manufacture of paint, rubber, polymer and other products for which chalk is used as a raw material provoked a sharp imbalance between its production and consumption. This was especially evident in the paper industry. Enterprises in this industry have special requirements for chalk powder, which has replaced kaolin in production.

The production of high-quality brands is concentrated at factories in the Belgorod region. In addition to the Shebekinsky enterprise, which produces separated chalk, new plants were created. So, in 1995, a processing plant appeared at Lebedinsky GOK - ZAO Ruslime. It was built according to the Spanish project of the company "Reverte" with an estimated capacity of 120 thousand tons / year. The plant produces up to 10 different grades of chalk. In terms of quality, they are in no way inferior to foreign counterparts and meet international standards. The enterprise is equipped with the most modern technological equipment, operations on the lines are mechanized and automated.

According to the project of Mabetex company, a plant was built at Stoilensky GOK with a capacity of 300 thousand tons of high quality chalk products. At the same time, the plans of the enterprise provide for a subsequent increase in capacity.

Breed blooming

One of the key criteria in the process of analyzing the physical properties of rock at a new deposit or site involved in an existing processing line is the behavior of chalk during grinding. As mentioned above, in different reservoir layers, the substance has different mechanical characteristics. Visually identifying these differences is not possible in most cases. Determining the behavior of chalk in the process of its dry grinding in the technological process is carried out by establishing an indicator of its blooming in a humid environment under mechanical action. For this, special equipment is used.

sodium bicarbonate

For its production, different materials are used, including limestone or chalk. The beneficial properties for the body that sodium bicarbonate possesses are known to many. Often it is used for diseases of the gums and throat, heartburn, to thin sputum when coughing. In industry, the physical properties of soda and chalk are in great demand. Both of these substances are used in construction, decoration, materials, paints and other products. With regard to the production of calcium bicarbonate, the use of chalk alone is considered an uneconomical option. As mentioned above, this rock absorbs moisture very well, as a result of which its mechanical characteristics change. This, in turn, negatively affects the course of the technological process.

Is it possible to eat CaCO 3?

It is widely believed that doctors recommend using medical chalk. The properties of this substance are believed to help replenish calcium deficiency. First of all, it should be said that doctors are ambiguous about this. Often, patients who like to eat chalk (food) turn to specialists. Useful however, are rather doubtful. Cravings for eating it may occur due to a lack of calcium. However, you should be aware that the characteristics of the substance undergo significant changes when it enters the stomach. Passing through several oxidative processes, it loses its original neutrality and turns into a reagent. In its action, the substance is similar. As a result, oxidized chalk begins to influence the gastric mucosa. In this case, no medicinal properties are manifested. Rather, on the contrary. It is worth remembering that the concentration of calcium in the substance is very high. As a result, excessive use of chalk can provoke liming of vessels. In this regard, doctors recommend replacing it with calcium gluconate or similar drugs. As for getting rid of heartburn, according to many people who have tried to eliminate it with chalk, it does not help in this.

Industrial and domestic use

Chalk acts as a necessary component of paper, which is used in printing. The high dispersion of calcium carbonate in crushed form affects the optical and printing characteristics, porosity, and smoothness of products. Due to the presence of chalk, the abrasiveness of products decreases. The ground rock is widely used for whitewashing walls, borders, and protecting trees. Chalk is used in the purification of beet juice, which, in turn, is used in the match industry. For these purposes, as a rule, the so-called precipitated rock is suitable. Such chalk is obtained chemically from calcium-containing minerals. Along with other carbonate rocks, the substance is used in glass melting as one of the charge components. Due to the chalk, the thermal stability of the product, its mechanical strength and stability when exposed to weathering and reagents are increased. The breed is widely used in the manufacture of fertilizers. Also, chalk is added to feed for farm animals.

Rubber industry

Chalk is in first place among all the fillers used in the industry. This is primarily due to the fact that the use of this raw material is economically beneficial. Chalk has a relatively low cost. At the same time, its introduction into rubber products does not cause harm. The second reason for the popularity of raw materials in the industry is technological expediency. Chalk greatly simplifies the process of manufacturing rubber products. In particular, due to it, vulcanization is accelerated, the surface of the products becomes smooth. The breed is also widely used in the production of sponge and porous rubber, plastic products, leather substitutes, and so on.

Chalk is a sedimentary rock of organic origin. The structure of the material is fine-grained, crumbly and soft, weakly cemented. Natural chalk is white. It does not dissolve in water. The mineral composition resembles limestone.

Chalk includes:

• skeletal fragments;
• foraminifera shells;
• seaweed fragments;
• fine calcite;
• insoluble minerals.

A careful analysis of the Cretaceous sediments reveals impurities in the form of very small grains of quartz. Cretaceous deposits may contain fossils dating back to the Cretaceous period: ammonites and belemnites. Natural chalk is not characterized by layering and recrystallization. Numerous burrows of soil-eating animals are included in the structure of the material.

Calcite, which dominates in the complex composition of chalk, can be of both autogenic and biogenic origin. Up to 75% of the rock is composed of organic remains. In their bulk, they are represented by skeletons and shells of plankton and foraminifers. Skeletal remains in the composition of chalk are very small - only 5-10 microns. This substance may also contain the skeletons of bryozoans, shells of mollusks, the remains of sea urchins, corals, flint sponges.

Up to 10% of the volume of chalk are impurities of the non-carbonate type:

• kaolinite;
• glauconite;
• feldspars;
• quartz;
• pyrite;
• opal;
• chalcedony.

Flint and phosphorite are much less common.

Cretaceous strata often cross large cracks filled with chalk flour. The network of such cracks usually thickens closer to the surface. At different levels of horizontal layers, chalk differs in its mechanical properties and chemical composition.

According to the structural properties and physical characteristics, three types of chalk are distinguished:

• white writing;
• marly;
• chalky limestone.

Chalk chemical properties

The chemical composition of chalk is determined by the high content of calcium carbonate with inclusions of magnesium carbonate. The chalk may also contain a non-carbonate part, including metal oxides. It is generally accepted that the chemical formula of this substance corresponds to the well-known formula of calcium carbonate (CaCO3). But the real composition of chalk is more complicated. This mineral contains about half of calcium oxide. Up to 43% of the chalk composition is carbon dioxide; it is in a bound state. Approximately 2% of the total mass of the substance is magnesium oxide. Mandatory, although not too significant, inclusions of quartz. Chalk with a relatively high silicon content has a higher density. Chalk contains a small amount of aluminum oxide, and iron oxides quite often color chalk layers red.

The carbonate part of the chalk is soluble in hydrochloric and acetic acids. The non-carbonate part includes quartz sand, clays, and metal oxides. Some of these components do not dissolve in acids. In small quantities, the chalk includes particles of magnesian calcite, as well as dolomite and siderite.

The molecular formula of chalk corresponds to several types of crystalline compounds that contain ions in the lattice sites.

Physical properties of chalk

Chalk is considered a semi-rock of a hard type. The strength of this mineral is determined by moisture. When water is exposed to chalk, the strength characteristics of chalk decrease. Changes often occur already at 2% humidity. At 35% humidity, the compressive strength increases by about 2-3 times, the chalk becomes plastic. This physical property makes it difficult to process the substance. Chalk begins to actively stick to the working parts of the machines. The viscosity and plasticity of chalk often do not allow it to be extracted from the lower horizons.

The density of chalk reaches 2700 kg/cu. m; porosity - up to 50%. Humidity in natural environment ranges from 19 to 33%. If the chalk is moistened, its strength is markedly reduced. At a moisture content of about 30%, chalk exhibits its plastic properties. Chalk found in nature is not resistant to frost. After multiple cycles of freezing and thawing, the chalk usually breaks into small pieces.

When analyzing the physical properties of chalk, special attention is paid to the behavior of the rock during grinding. In the technological process, it is customary to set the rate of chalk blooming in a humid environment with controlled mechanical action. The modulus of elasticity of chalk for a loose state is 3000 MPa, for compacted - 10000 MPa. Temporary compressive strength: 1000-4500 MPa.

Calcium carbonate, being in a crushed form, has a high dispersion. The presence of chalk in the product reduces its abrasiveness. The physical properties of this substance help to increase the thermal resistance of products, their mechanical strength, resistance to weathering and exposure to reagents.

Previously, it was believed that the chemical and physical properties of chalk are the same for all deposits. However, practice has shown that this is not the case. The properties of Cretaceous deposits differ even within the same deposit. Therefore, when mining a mineral by industrial means, technological mapping is performed. The chemical properties of chalk and its physical characteristics are studied in different areas of the deposits. Places of accumulation of high-quality chalk rocks are put on the maps.

Chalk deposits

The richest deposits of chalk are located in Europe. It can be found from Western Kazakhstan to the British Isles. The thickness of the chalk layers reaches hundreds of meters. Deposits with a thickness of up to 600 m were found in the Kharkov region. A huge chalk belt stretches across Europe, capturing the northern part of France, the south of England, Poland, Ukraine, and Russia. Part of the deposits is displaced to Asia; chalk reserves are found in the Libyan desert and in Syria.

In the United States, chalk deposits have been noted only in the southern and central states. However, the chalk there is of poor quality; for this reason it has to be imported into the US from Denmark, the UK and France.

Chalk reserves are distributed very unevenly. Up to half of high-quality chalk with a good content of calcium carbonate is concentrated in the Russian Federation. In absolute terms, chalk reserves in Russia are estimated at 3,300 million tons. Unlimited forecast chalk deposits are located in the Belgorod region. Very high quality chalk with a low content of non-carbonate impurities is mined in the Voronezh region.

The practical value of chalk

The practical use of chalk is determined by its chemical and physical properties. In industry, it is used for the production of cement, lime, soda, glass and school crayons. Chalk also serves as a filler for plastics, paper, rubber, paints and varnishes. It is included in the formulation of toothpastes and powders.

Chalk also finds application in agriculture: it is used for liming the soil and as a top dressing for animals, to protect tree trunks from sunburn.

Chalk is a necessary component in the production of coated paper. It is widely used in the printing industry for the manufacture of illustrated publications. Chalk is successfully used as the main filler and pigment in the manufacture of cardboard.

Chalk also finds application in construction. Cheap ground chalk is used for whitewashing, priming, wall painting.

YULIA KARPENKO

An object

Item research - chalk.

Target

Hypothesis

1. Study the literature on chalk.

2. Study information about the use of chalk in everyday life and at work.

3. Conduct a survey.

4. Process the results of the survey.

5. Take stock.

Download:

Preview:

Research

" Chalk "

Work completed

4th grade student

MOU "Secondary school r.p. Ozinki"

Karpenko Julia

Head: Panitskaya T.I.

Ozinki 2015

Introduction ……………………………………………………………………...

Relevance of the work, problem, research methods………………….

Purpose, objectives……………………………………………………………………..

Origin, properties and application of chalk....................................................

Questionnaire for teachers and students…………………………………………...

Analysis of questionnaires……………………………………………………………………

Conclusion…………………………………………………………………...

List of sources…………………………………………………………..

Introduction

Who among us does not know chalk? Whose pockets and fingers were not soiled by a piece of light stone the color of snow in childhood? Who does not know the happiness of the artistic creation of the "Cretaceous" period? Who, as a teenager, did not investigate the properties of chalk in "bubble" experiments, did not examine a chalk smear under a microscope?

What secrets does chalk hold? Sometimes a piece of chalk suddenly began to scratch the board, and Tatyana Ivanovna told us that these were the remains of ancient shells. And here is a simple piece that interested me.

An object my research is minerals.

Item research - chalk.

Target research: study chalk as a mineral, find out its origin, where it occurs in nature, where it is used in everyday life and in production.

Hypothesis my project is that chalk plays an important role in our lives.

For myself, I have defined the stages of research activity:

1. Study the literature on chalk.
2. To study information about the use of chalk in everyday life and at work.
3. Conduct a survey.
4. Process the survey results.
5. Summarize.

Tasks:

1. Collect reliable information about the origin, composition, properties and use of school chalk.

2. Conduct a sociological survey to identify the effect of chalk on the human body.