Methods for obtaining zinc chloride. Zinc Chloride: Composition and Molar Mass Zinc chloride is used as

Zinc chloride is a chemical compound of two elements - chlorine and zinc - and is designated by the formula ZnCl2. This substance is white crystals.

Zinc chloride dissolves quite easily in water - at room temperature its solubility is 80%. Chloride melts at 322°C and boils at 722°C.

Zinc chloride is obtained in two ways. The first option: zinc or its oxide is dissolved in hydrochloric acid, after which the solutions are evaporated from the resulting mixture. Second option: zinc (in liquid state) is heated in a stream of chlorine.

Hydrolysis of zinc chloride occurs by cation and has the following formula: ZnCl2 + H2O = ZnOHCl + HCl. The resulting solution is acidic.

Industrially produced zinc chloride is available in two forms: solid and liquid. In solid form, the substance should have the appearance of white flakes; slight staining of any color is acceptable. In the form of a solution, the chloride should be colorless or have a slight yellowish tint. The solution may be slightly cloudy.

In solid form, chloride should not be less than 97.7%, in solution - 50%. Zinc chloride is not flammable.

The substance is very dangerous for the environment and humans: it has degree 2 toxicity. The substance, upon contact with the skin and mucous membranes of a person or animal, causes irritation; with longer contact with the skin, it causes burns and corrodes tissue. Wounds formed in this way are very difficult to heal.

There is also a danger if the substance enters the respiratory tract. In small doses it causes soreness in the nasopharynx and throat, and a dry cough. Inhalation of large amounts of chloride may cause shortness of breath and so-called wheezing.

If the substance gets into the mucous membrane of the eye, the victim experiences quite intense cutting pain. If the eyes are not washed immediately, total or partial blindness may occur.

Due to the toxicity of zinc chloride, extreme care must be taken when transporting and using it. Crystalline zinc chloride is packaged in bags or drums and the solution is transported in steel barrels or special tanks.

Transportation of the substance is carried out both by rail and by road, and the substance is transported only in covered compartments and the responsible person is obliged to monitor the integrity of the packaging during transportation.

When working with zinc chloride, workers are required to wear protective clothing, rubberized gloves, and respirators that correspond to the level of concentration of the substance in the air.

Under no circumstances should zinc chloride be allowed to enter water bodies or sewerage systems.

Zinc chloride is used in many areas of production. It is used to impregnate wooden parts for disinfection (for example, wooden sleepers). This substance is involved in the manufacture of fiber, many dyes, many dental cements, cotton, zinc cyanide, aluminum and even vanillin. In addition, zinc chloride is used to clean metal surfaces before painting, soldering and chrome plating. This substance also plays a significant role in oil refining, analyzing coal samples and making voltaic batteries.

Zinc chloride is also used for dyeing chintz, producing viscose fibers, and as an electrolyte for galvanizing. It is possible to use the substance in medicine - as a drug that stops rotting; in gardening - as a microfertilizer.

In addition, zinc chloride, due to its brilliant ability to greedily absorb moisture from the air, is used as a desiccant. It is also indispensable in the fire department, as it is involved in the production of fire-resistant foam and the impregnation of fabrics and cardboard.

Zinc chloride, despite its unsafety for the skin and respiratory organs of humans, is a fairly useful and widely used remedy. Its use is based on its specific chemical properties as a drying and fire-retardant substance.

Fabrics and paper are impregnated with zinc chloride, thereby ensuring their fire safety. It is able to perfectly protect wood from various pathogens, which is used in almost all areas of construction. In industry, zinc chloride is invaluable as a dye for natural products, as well as in the production of rubber products, fiber, vanillin, etc.

Heavy industry also pays attention to zinc chloride. With its use, it is currently possible to effectively purify petroleum products, smelt high-quality aluminum, galvanize, tin, lead and chrome plating metal products, and carry out galvanic processes.

The production of zinc chloride is carried out by evaporating a solution of zinc (or zinc oxide) with hydrochloric acid. As a zinc component, you can use waste of non-ferrous metals - zinc scrap, dust, as well as specific waste from the textile industry, called okshara.

About safety precautions when working with zinc chloride

Considering the high degree of danger to humans and the impossibility of fully automating production lines, strict labor protection requirements must be adhered to when handling zinc chloride:

1. When working with the substance, you must wear rubberized gloves, shoes, an apron and safety glasses.
2. There should always be ventilation in the room.
3. Vessels containing the substance should not be left open.
4. It is prohibited to eat food in premises where work with the substance is carried out.
5. Do not wash charcoal treated with the substance with a strong stream of water to avoid splashing.
6. Damaged vessels and instruments must not be used for work.
7. If the solution gets on the skin, immediately rinse with water and a small amount of soda.

Since zinc chloride is extremely hygroscopic, polypropylene bags or two-layer paper bags with a polypropylene inner layer are used for its packaging.

Application of zinc chloride

• used in the textile and engineering industries,
• used in the preparation of electrolyte for dry cells and galvanic baths in electroplating,
• fluxes for hot-dip galvanizing, tinning, lead plating;
• fluxes for manual and machine soldering;
• in the production of fiber, for wood antiseptic, as an additive for rubber vulcanization,
• as a solvent for cellulose cord during rubber regeneration,
• in chemical synthesis as a dehydrating agent and catalyst.

Zinc chloride - features

Zinc chloride very actively absorbs moisture, so for storage and transportation use polyethylene or paper bags with an additional sealed polyethylene liner.

Standard quality indicators for zinc chloride

Appearance of zinc chloride

White crystalline powder. Fire and explosion proof.

Guaranteed shelf life is 3 years from the date of manufacture.

Zinc Chloride (Zinc Chloride, Zinc Dichloride, Soldering Acid)– a chemical compound of zinc with chlorine.

Physicochemical characteristics.

Formula ZnCl 2. White powder. Density 2.91 g/cm3. Melting point - 318°C. The melted preparation is a transparent porcelain mass. Boiling point 732°C. At 650÷700°C, thick white smoke of sublimating ZnCl 2 is formed. It is extremely hygroscopic, moist air passed over ZnCl 2 contains only 0.98 mg/l H 2 O. In the temperature range 12.5÷26°C it can exist in the form of ZnCl 2 × 1.5H 2 O hydrate with a melting point of 26 °C, which is very soluble in water, ethanol, glycerin.

Solubility of zinc chloride in various solvents

Application.

Zinc chloride (zinc chloride) is used:
- as a drying agent;
- in fire protection for fire protection (fire-resistant foam, impregnation of cardboard and fabrics);
- for antiseptic impregnation of wood, sleepers;
- in fiber production;
- in the chemical industry for the production of vanillin and zinc cyanide;
- in technological processes for the production of dyes and cotton dyeing;
- in the oil industry during oil refining;
- in metallurgy in the production of metals such as aluminum, in soldering processes, in the preparation of metal products for galvanizing and chrome plating;
- in galvanic batteries and for other purposes.

Activated carbon is a product of heat treatment of carbon-containing raw materials (wood, peat, coal), which has a porous structure and due to this a large surface area. Used to purify gases and liquids from impurities.

The use of zinc chloride in activated carbon production technology makes it possible to obtain activated carbon with high technical performance.

For example, for activated carbon from birch sawdust, treatment with zinc chloride makes it possible to increase the specific surface area by 20 times from 50 m 2 /g to 1000 m 2 /g compared to untreated activated carbon.

The technology for the production of activated carbon using zinc chloride for birch sawdust 5 mm in size is carried out in three stages.

1. First, the starting material is impregnated with an aqueous solution of zinc chloride (0.5 kg of zinc chloride per 1 kg of sawdust). Then drying is carried out for 50-70 hours at a temperature of 102-105 ° C. Drying is carried out until the weight of the material stops decreasing.

2. Heat treatment (carbonization) is carried out in a horizontal flow reactor in an argon flow at 25–800 °C with a heating rate of 10 °C/min and holding at the final temperature for 30 minutes. with a horizontal flow reactor in argon flow

3. Rinsing the products with water for 1.5 hours at a temperature of 60 degrees C until a neutral environment.

This product has a pore size of 0.5-3 microns and a fibrous texture. Specific surface 1000 m 2 /g.

Electrolytic zinc-cobalt coatings are used instead of cadmium coatings in shipbuilding. These coatings are highly corrosion resistant in marine environments, but unlike cadmium coatings, they are cheaper and less toxic.

The zinc-cobalt coating was applied using an electrolyte of the following composition (g/l):

Zinc chloride (in terms of metal) 30-40;

Cobalt (II) chloride (in terms of metal) 10-20;

Ammonium chloride 20-260;

Boric acid 20-30;

Bone glue 2-3.

The preparation of an electrolyte for the electrodeposition of a zinc-cobalt alloy to replace the toxic cadmium plating electrolyte is carried out as follows:

1) The calculated amount of ammonium chloride is dissolved and the solution is introduced into the galvanic bath;

2) Dissolve the calculated amount of zinc chloride in a separate container and add it to the ammonium chloride solution;

3) Dissolve cobalt chloride and add it to the ammonium chloride solution;

4) The calculated amount of boric acid is introduced into the electrolyte, which is first dissolved in hot water.

The electrolyte must be kept for 24 hours to form complexes of zinc and cobalt. The electrolyte is filtered, the pH of the electrolyte is adjusted to the required value and processed at a current density of 0.5-0.7 A/dm 2 for 2-3 hours. Then the additive TsKN-3 or glue is introduced. The glue must first be soaked in warm water (t=40-45 °C). After introducing the adhesive or additive, the electrolyte must be worked in operating mode for 1 hour until a coating of the required quality is obtained.

The electrolyte is adjusted according to chemical analysis data for zinc and cobalt. A complex salt of zinc and cobalt is introduced into the electrolyte. The addition of glue or TsKN-3 is carried out according to the appearance of the coating. The pH of the electrolyte is adjusted by adding ammonium hydroxide or hydrochloric acid (1:2).

Production of laboratory samples of zinc-cobalt coating:

1) The sample to be coated is degreased in an alkaline environment;

2) Washing the sample in distilled water at a temperature of 298K;

3) The sample is etched in an acid solution, the composition of which depends on the base material. In the case of a copper sample, etching is carried out in a mixture of nitric and hydrochloric acids. In the case of a steel base, etching is carried out in hydrochloric acid;

4) Washing the sample in distilled water at a temperature of 298K.

A saturated solution of zinc chloride is used as a flux when soldering with soft low-tin solders POS-18, POS-30, etc. This flux is used in cases where the corrosive effect of flux residues is not important and special strength is not required from the solder. In this way, products made of zinc, galvanized iron, iron, brass, and copper are soldered.

Zinc chloride is part of a paste-like flux for brazing stainless steel. This flux is produced as follows. Crystalline sodium tetraborate and boric acid are mixed in equal quantities. The powder mixture is then added to a saturated aqueous solution of zinc chloride until a paste-like consistency is obtained.

In addition, zinc chloride is used together with ammonium chloride as a flux when melting and pouring sliding bearings based on cadmium alloys.

Wood is a material that is not very resistant to rot (infection with spores of wood-decaying fungi).

To operate wooden products near sources of fungal infection (temperature from +2 to +45 °C, humidity more than 25%), wood is impregnated with an antiseptic - a saturated solution of zinc chloride. For example, the average duration of railway service sleepers impregnated with zinc chloride are: pine - 15 years; spruce, beech - 10 years; oak - 18 years old. Impregnation is carried out under pressure or in open baths by immersion.

Receipt.

Zinc chloride is obtained by dissolving zinc or its oxide in hydrochloric acid, followed by evaporation of the solutions or by heating liquid zinc in a stream of chlorine.

Zinc chloride (zinc chloride, zinc dichloride), denoted by the formula ZnCl 2 and is a compound of two chemical elements - zinc and chlorine. It is a colorless, highly hygroscopic, crystalline substance with caustic properties. Zinc chloride is soluble in ether, ethanol, glycerin and acetone. Concentrated aqueous solutions of zinc chloride dissolve starch, silk and cellulose, and that is why such a liquid is a medium strength Lewis acid. A Lewis acid is any compound that can accept an electron pair into an unfilled orbital. In other words, a Lewis acid is an electron pair acceptor.

Zinc chloride is a white crystalline substance with a density of 2.91 g/cm³ and a melting point of 322°C. The product is highly soluble in water, with an average compound solubility of 80 percent. Thus, 368 g of zinc chloride dissolves in 100 g of water at 20°C, and 614 g at 100°C. When zinc chloride is dissolved in water, the solution heats up due to the chemical interaction of the substance with the solvent. Zinc dichloride solutions are acidic; the pH of solutions usually varies from 1.5 to 3.5.

Zinc chloride always contains some amount of water, because... it is hygroscopic. Due to its good solubility, this substance can completely dissolve in hygroscopic water and form viscous, thick solutions with high density. Typically, the composition of a zinc chloride solution must be adjusted after determining its density using a hydrometer (a device for measuring the density of liquids and solids).

Zinc chloride has chemical properties that are characteristic of soluble zinc salts. It can be obtained by dissolving zinc or its oxide in hydrochloric acid, heating liquid zinc in a stream of chlorine, or displacing other metals from their compounds (chlorides) with zinc.

The industrial method of production is the dissolution of zinc and its compounds in hydrochloric acid. Both pure zinc and its oxides and even zinc-containing secondary raw materials are suitable for this method. Subsequently, the resulting solution is evaporated, since the final product, in addition to zinc chloride, will be water or volatile gases. The second industrial method for producing ZnCl 2 is heating liquid zinc in a stream of chlorine. To do this, granulated zinc is melted at a temperature of 419.6 °C (zinc melting point).

In laboratories, zinc dichloride can be obtained by the action of pure zinc on solutions of chlorides of certain metals. Those metals that are to the right of zinc in the electrochemical series of voltages will be displaced by it from the compounds. The most common metals included in the reagents are copper, iron, mercury and silver. Another method for obtaining zinc chloride in laboratories is the action of metal chlorides or hydrochloric acid on zinc compounds.

Purification of zinc chloride occurs by sublimation (transition of a substance from a solid state to a gaseous state without remaining in a liquid state) at a temperature of 600°C - 700°C in a stream of chlorine.

Technical zinc chloride is supplied in industrial packaging:

• cargo is transported by rail, road and sea transport in closed compartments;
• transported in sealed original packaging;
• during transportation, the safety and integrity of the packaging should be ensured and zinc chloride should not be allowed to come into contact with the external environment;
• it is necessary to store the product in closed warehouses in sealed original packaging;
• during storage and use, the required safety measures for the product should be ensured and its spillage should not be allowed;
• It is recommended to store zinc chloride separately from food.

Subject to the conditions of transportation and storage in unopened original packaging, the guaranteed shelf life of zinc chloride is 12 months.

Zinc chloride is a useful substance widely used in industry. Its use is based on its specific chemical properties as a drying and fire-retardant agent.

The most common areas of use of zinc chloride:

• in the production of fire retardants, such as fire-resistant foam, impregnation of fabrics and cardboard;
• in the oil industry for killing oil wells;
• as an antiseptic impregnation of wood and railway sleepers;
• in the chemical industry in the production of zinc cyanide;
• in technological processes for the production of dyes;
• in metallurgy in the production of aluminum and in the processes of soldering steel or copper cases, screens, also as a flux for cleaning metals before soldering;
• used in the preparation of electrolyte for dry cells and galvanic baths in electroplating;
• in the textile industry as a paint fixer when dyeing fabrics;
• in the coal mining industry when testing coal samples for fractional composition;
• as a catalyst in organic synthesis for alkylation, Friedel-Crafts acylation;
• during hot-dip galvanizing (galvanizing in molten zinc).

Chloride zinc– a white chemical compound that is hygroscopic. It is highly soluble in water and has a crystalline structure when dry. Has chemical properties classic for soluble salts zinc. Can be obtained by dissolving zinc or its oxide in hydrochloric acid, by heating liquid zinc in a flow of chlorine, by zinc displacing other metals from their compounds (chlorides).

Instructions

1. Industrial method of acquisition - dissolution zinc and its compounds in hydrochloric acid. Roasted ore can serve as the starting material. In the future, the resulting solution is evaporated, because final product other than chloride zinc, there will be water or volatile gases. Zn + 2 HCl = ZnCl? + H??ZnO + 2 HCl = ZnCl? + H?OZnS + 2 HCl = ZnCl? +H?S?

2. Another industrial method for acquiring ZnCl? – heating liquid zinc in a stream of chlorine. To do this, granulated zinc is melted at a temperature of 419.6 °C (melting point zinc).Zn + Cl? =t= ZnCl?

3. Chloride in the laboratory zinc allowed to receive through the action of pure zinc to solutions of chlorides of certain metals. Those metals that are to the right zinc in the electrochemical series of voltages will be displaced by it from the compounds. Particularly common metals included in the reagents are steel, copper, mercury and silver. To carry out the reaction, pour a small amount of ferric chloride solution (copper, mercury or silver) into a test tube. After this, place the granules of pure zinc or a zinc plate.2 FeCl? + 3 Zn = 3 ZnCl? + 2 Fe Because The solution of iron III chloride is yellow in color, then after the reaction the solution will become discolored, and pure steel will precipitate. This will provide visual confirmation that the reaction was successful.CuCl? + Zn = ZnCl? + CuHgCl? + Zn = ZnCl? + Hg2 AgCl + Zn = ZnCl? + 2 Ag

4. Another laboratory method for acquiring chloride zinc– the effect of metal chlorides or hydrochloric acid on compounds zinc. To carry out the reaction, pour the calculated amount of hydroxide into the test tube zinc, add an equal amount of hydrochloric acid. After the neutralization reaction, a colorless chloride solution is formed zinc. If you need to obtain the substance in dry form, pour the solution into an evaporation cup and place it on an electric stove. After evaporation, a white precipitate or coating should remain on the walls of the test tube. Zn(OH)? + 2 HCl = ZnCl? + 2 H?O Required number of sulfate zinc pour into a test tube and add barium chloride. If the calculation is correct, the substances will react with each other completely (without residue) and the final products will separate. Barium sulfate will precipitate, and barium chloride zinc will remain in solution. You can filter the precipitate and evaporate the solution. ZnSO? +BaCl? = ZnCl? +BaSO??

Chlorides are called compounds of metals with chlorine. Chlorides are salts. The chlorine atoms in the composition of chlorides can be interpreted as acidic residues of hydrochloric acid. Thus, chlorides can be considered as salts of metals and hydrochloric acid. Obtaining chloride at home is not a special task. Sodium chloride is especially easy to obtain.

You will need

• Hydrochloric acid (sold in pharmacies). Sodium bicarbonate (baking soda, available in stores). Glass retort. Glass or iron spatula or spoon.

Instructions

1. Prepare a solution of hydrochloric acid. If the acid is concentrated, it must be diluted. Pour water into the retort. Add acid in a thin stream, continuously stirring the solution. If the hydrochloric acid solution is not concentrated, easily pour it into the retort. The amount of hydrochloric acid solution in the retort should not be huge in order to prevent it from splashing out during the reaction.

2. Prepare sodium bicarbonate. Usually it is a powder, but it tends to cake when exposed to moisture, forming lumps. If the sodium bicarbonate powder contains clumps, remove them or break them into small pieces.

3. Carry out the reaction of neutralization of hydrochloric acid solution with crystalline sodium bicarbonate. Pour sodium bicarbonate in small portions into the retort. A rather crazy reaction will occur with the release of large amounts of carbon dioxide. After adding any portion of sodium bicarbonate, wait for the reaction to complete and lightly shake the solution. When the reaction stops, stop adding sodium bicarbonate powder. A solution of sodium chloride, that is, ordinary table salt, formed in the retort.

Note!
Be careful when working with acid. Wear gloves and safety glasses. If acid gets on your skin, wash the area with an aqueous solution of sodium bicarbonate. It neutralizes the effect of acid.

Helpful advice
In order to obtain as pure a solution of sodium chloride as possible, you can add small fractions of a solution of sodium bicarbonate in water. In this case, it is allowed to use indicators of the acidic state of the environment to determine the moment of maximum reduction in the concentration of hydrochloric acid. If you need to obtain crystalline sodium chloride, after carrying out the acid neutralization reaction, the resulting solution can be simply evaporated.

Ammonium chloride is a colorless crystalline substance, soluble in water and slightly hygroscopic. It is used in the pharmaceutical industry, metallurgy, and for the production of fertilizers. It can be obtained both in industrial and laboratory conditions.

You will need

• – volumetric flask
• – test tube
• – reagents (HCl, NH?OH, (NH?)?SO?, NaCl)

Instructions

1. Industrial method for producing ammonium chloride: pass carbon monoxide (IV) through ammonia and sodium chloride. As a result of the reaction, sodium bicarbonate and ammonium chloride are formed. The reaction takes place under ordinary conditions without the addition of catalysts. NH? +CO? +H?O+NaCl=NaHCO? +NH?Cl

2. In the laboratory, NH?Cl can be obtained by the action of ammonium hydroxide on a solution of hydrochloric acid. No additional data is required. Carrying out the reaction. Using the chemical equation, calculate how many initial substances you need to take. Pour the calculated amount of hydrochloric acid (HCl) into the test tube, add ammonium hydroxide solution. Result. As a result of neutralization of the acid with hydroxide, salt (ammonium chloride) and water are formed.NH?OH+HCl=NH?Cl+H?O

3. Another laboratory acquisition method is the interaction of 2 salts. Carrying out the reaction. Calculate the number of substances that react. Measure out the sodium chloride solution and add the ammonium sulfate solution. Summary. The reaction takes place in two stages. Ammonium sulfate reacts with sodium chloride. The sodium ion displaces the ammonium ion from its compound. At the intermediate stage, sodium sulfate is formed, which does not participate in the future reaction. At the 2nd stage, ammonia reacts with hydrochloric acid solution. The visual result of the reaction is the release of white smoke.(NH?)?SO? +NaCl=Na?SO? + 2HCl+ 2NH??HCl+NH? =NH?Cl To purchase ammonium chloride in the laboratory, they use a special device in order to obtain the required substance in solid form. Because As the temperature increases, ammonium chloride breaks down into ammonia and hydrogen chloride.

Video on the topic

Note!
Ammonia and its salts have an irritating effect on the mucous membrane (it has a strong smell). Therefore, when working with it, you must follow safety precautions: - do not inhale ammonia vapor; - keep the test tubes with reagents at a distance from your face.