Aluminum oxide is a solid. Applications of aluminum. Aluminum oxide dental crowns: fabrication and installation

We send it up into the air and launch it into space, put it on a stove, build buildings out of it, make tires, smear it on the skin and treat an ulcer with it ... Don't you understand yet? It's about aluminum.

Try to list all the applications of aluminum and you will definitely be wrong. Most likely, you are not even aware of the existence of many of them. Everyone knows that aluminum is a material for aircraft manufacturers. But what about the automotive industry or, say. medicine? Did you know that aluminum is an E-137 food additive that is commonly used as a colorant to give food a silvery tint?

Aluminum is an element that easily forms stable compounds with any metals, oxygen, hydrogen, chlorine and many other substances. As a result of such chemical and physical effects, alloys and compounds diametrically different in their properties are obtained.

Use of oxides and hydroxides of aluminum

The areas of application of aluminum are so extensive that in our country the use of marking of aluminum alloys has become mandatory to protect manufacturers, designers and engineers from unintended mistakes. Each alloy or compound is assigned its own alphanumeric designation, which in the future allows you to quickly sort them and send them for further processing.

The most common natural compounds of aluminum are its oxide and hydroxide. in nature they exist exclusively in the form of minerals - corundum, bauxite, nepheline, etc. - and as alumina. The use of aluminum and its compounds is associated with jewelry, cosmetology, medicine, chemical industry and construction.

Colored, "pure" (not cloudy) corundums are jewels known to all of us - rubies and sapphires. However, at their core, they are nothing more than the most common aluminum oxide. In addition to the jewelry industry, the use of aluminum oxide extends to the chemical industry, where it usually acts as an adsorbent, as well as to the production of ceramic dishes. Ceramic pots, pots, cups have remarkable heat-resistant properties precisely because of the aluminum they contain. Aluminum oxide has found its application as a material for the manufacture of catalysts. Often, aluminum oxides are added to concrete for its better hardening, and glass, to which aluminum is added, becomes heat-resistant.

The list of applications for aluminum hydroxide looks even more impressive. Due to its ability to absorb acid and have a catalytic effect on human immunity, aluminum hydroxide is used in the manufacture of drugs and vaccines against hepatitis A and B and tetanus infection. They are also treated for renal failure due to the presence of a large number of phosphates in the body. Once in the body, aluminum hydroxide reacts with phosphates and forms inseparable bonds with them, and then is naturally excreted from the body.

Hydroxide, due to its excellent solubility and non-toxicity, is often added to tooth brushing paste, shampoo, soap, mixed with sunscreens, nourishing and moisturizing face and body creams, antiperspirants, tonics, cleansing lotions, foams, etc. If necessary uniformly and persistently dye the fabric, then a little aluminum hydroxide is added to the dye and the color is literally "etched" into the surface of the matter.

The use of chlorides and aluminum sulfates

Chlorides and sulfates are also extremely important aluminum compounds. Aluminum chloride does not occur naturally, but it is quite easy to obtain it industrially from bauxite and kaolin. The use of aluminum chloride as a catalyst is rather one-sided, but practically invaluable for the refining industry.

Aluminum sulfates exist naturally as minerals in volcanic rocks and are known for their ability to absorb water from the air. The use of aluminum sulphate extends to the cosmetic and textile industries. In the first, it acts as an additive in antiperspends, in the second, as a dye. It is interesting to use aluminum sulfate in insect repellents. Sulfates not only repel mosquitoes, flies and midges, but also numb the bite site. However, despite the tangible benefits, aluminum sulfates have ambiguous effects on human health. If aluminum sulfate is inhaled or swallowed, serious poisoning can occur.

Aluminum alloys - main applications

Artificially obtained compounds of aluminum with metals (alloys), in contrast to natural formations, can have such properties as the manufacturer himself wishes - it is enough to change the composition and amount of alloying elements. Today, there are almost limitless possibilities for the production of aluminum alloys and their applications.

The most famous industry for the use of aluminum alloys is aircraft construction. The aircraft are almost entirely made of aluminum alloys. Zinc, magnesium and aluminum alloys provide unprecedented strength used in aircraft skin and structural parts.

Aluminum alloys are used in a similar way in the structure of ships, submarines and small river transport. Here, it is most profitable to make superstructure structures from aluminum, they reduce the weight of the vessel by more than half, while not compromising their reliability.

Like planes and ships, cars are becoming more and more "aluminum" every year. Aluminum is used not only in body parts, but now it also includes frames, beams, pillars and cab panels. Due to the chemical inertness of aluminum alloys, low susceptibility to corrosion and thermal insulation properties, tanks for the transport of liquid products are made from aluminum alloys.

The use of aluminum in industry is widely known. Oil and gas production would not be as it is today if it were not for the extremely corrosion-resistant, chemically inert aluminum alloy pipelines. Drills made of aluminum weigh several times less, which means they are easy to transport and install. And that's not talking about all sorts of things, tanks, boilers and other containers ...

Pots, pans, baking trays, ladles and other household utensils are made from aluminum and its alloys. Aluminum cookware perfectly conducts heat, heats up very quickly, while being easy to clean, does not harm health and food. On aluminum foil, we bake meat in the oven and bake pies, butter and margarines, cheeses, chocolate and sweets are packed in aluminum.

An extremely important and promising area is the use of aluminum in medicine. In addition to the areas of use (vaccines, renal medicines, adsorbents) mentioned earlier, the use of aluminum in medicines for ulcers and heartburn should also be mentioned.

From all of the above, one conclusion can be made - the grades of aluminum and their applications are too diverse to devote one small article to them. It is better to write books about aluminum, because it is not for nothing that it is called "the metal of the future."

Aluminum oxide - Al2O3. Physical properties:aluminum oxide is a white amorphous powder or very hard white crystals. Molecular weight \u003d 101.96, density 3.97 g / cm3, melting point 2053 ° C, boiling point 3000 ° C.

Chemical properties:aluminum oxide exhibits amphoteric properties - the properties of acidic oxides and basic oxides and reacts with both acids and bases. Crystalline Al2O3 is chemically passive, amorphous is more active. Interaction with acid solutions gives medium aluminum salts, and with base solutions - complex salts - metal hydroxoaluminates:

When alloying aluminum oxide with solid alkalis of metals, double salts are formed - meta-aluminates(anhydrous aluminates):

Aluminum oxide does not interact with water and does not dissolve in it.

Receiving:aluminum oxide is obtained by the method of reduction of metals from their oxides by aluminum: chromium, molybdenum, tungsten, vanadium, etc. - metallothermia, open Beketov:

Application:aluminum oxide is used for the production of aluminum, in the form of a powder - for refractory, chemically resistant and abrasive materials, in the form of crystals - for the manufacture of lasers and synthetic precious stones (rubies, sapphires, etc.), colored with impurities of oxides of other metals - Cr2O3 ( red), Ti2O3 and Fe2O3 (blue).

Aluminum hydroxide - A1 (OH) 3. Physical properties:aluminum hydroxide - white amorphous (gel-like) or crystalline. Almost insoluble in water; molecular weight - 78.00, density - 3.97 g / cm3.

Chemical properties:a typical amphoteric hydroxide reacts:

1) with acids, forming medium salts: Al (OH) 3 + 3HNO3 \u003d Al (NO3) 3 + 3H2O;

2) with alkali solutions, forming complex salts - hydroxoaluminates: Al (OH) 3 + KOH + 2H2O \u003d K.

When Al (OH) 3 is fused with dry alkalis, meta-aluminates are formed: Al (OH) 3 + KOH \u003d KAlO2 + 2H2O.

Receiving:

1) from aluminum salts under the action of an alkali solution: AlСl3 + 3NaOH \u003d Al (OH) 3 + 3Н2О;

2) decomposition of aluminum nitride with water: AlN + 3H2O \u003d Al (OH) 3 + NH3?;

3) passing CO2 through a solution of the hydroxo complex: [Al (OH) 4] - + CO2 \u003d Al (OH) 3 + HCO3-;

4) the action of ammonia hydrate on Al salts; Al (OH) 3 is formed at room temperature.

62. General characteristics of the chromium subgroup

The elements chromium subgroupsoccupy an intermediate position in the series of transition metals. They have high melting and boiling points, free places in electronic orbitals. The elements chromiumand molybdenumhave an atypical electronic structure - they have one electron on the outer s-orbital (like Nb from the VB subgroup). These elements have 6 electrons on the outer d- and s-orbitals, so all orbitals are half full, that is, each has one electron. With a similar electronic configuration, the element is particularly stable and resistant to oxidation. Tungstenhas a stronger metallic bond than molybdenum... The oxidation state of elements of the chromium subgroup varies greatly. Under proper conditions, all elements exhibit a positive oxidation state of 2 to 6, with the maximum oxidation state corresponding to the group number. Not all oxidation states of the elements are stable; for chromium, the most stable is +3.

All elements form the oxide MVIO3; oxides with lower oxidation states are also known.All elements of this subgroup are amphoteric - they form complex compounds and acids.

Chrome, molybdenumand tungstenare in demand in metallurgy and electrical engineering. All considered metals are coated with a passivating oxide film when stored in air or in an acid-oxidizing medium. Removing the film by chemical or mechanical means can increase the reactivity of metals.

Chromium.The element is obtained from the chromite ore Fe (CrO2) 2, reducing with coal: Fe (CrO2) 2 + 4C \u003d (Fe + 2Cr) + 4CO ?.

Pure chromium is obtained by reduction of Cr2O3 using aluminum or electrolysis of a solution containing chromium ions. By separating chromium by electrolysis, it is possible to obtain a chromium plating used as decorative and protective films.

Ferrochrome is obtained from chromium, which is used in steel production.

Molybdenum.Obtained from sulfide ore. Its compounds are used in the production of steel. The metal itself is obtained by reducing its oxide. By calcining molybdenum oxide with iron, ferromolybdenum can be obtained. Used for the manufacture of threads and tubes for winding furnaces and electrical contacts. Steel with the addition of molybdenum is used in the automotive industry.

Tungsten.Obtained from oxide extracted from beneficiated ore. Aluminum or hydrogen is used as a reducing agent. The resulting tungsten in the idea of \u200b\u200ba powder is subsequently molded under high pressure and heat treatment (powder metallurgy). In this form, tungsten is used to make filaments and is added to steel.

Electronic configuration of the external aluminum level ... 3s 2 3p 1.

In an excited state, one of the s-electrons is transferred to a free cell of the p-sublevel; this state corresponds to valence III and oxidation state +3.

Free d-sublevels exist in the outer electron layer of the aluminum atom. Due to this, its coordination number in the compounds can be equal not only to 4 ([A1 (OH) 4] -), but also 6 - ([A1 (OH) 6] 3-).

Being in nature

The most widespread metal in the earth's crust, the total aluminum content in the earth's crust is 8, 8%.

It does not occur in free form in nature.

The most important natural compounds are aluminosilicates:

white clay Al 2 O 3 ∙ 2SiO 2 ∙ 2H 2 O, feldspar K 2 O ∙ Al 2 O 3 ∙ 6SiO2, mica K 2 O ∙ Al 2 O 3 ∙ 6SiO 2 ∙ H 2 O

Among other natural forms of finding aluminum, the most important are bauxites A1 2 Oz ∙ nH 2 O, minerals corundum A1 2 Oz and cryolite A1Fz ∙ 3NaF.

Receiving

At present, in the industry, aluminum is obtained by electrolysis of aluminum oxide A1 2 O 3 in a cryolite melt.

The electrolysis process is ultimately reduced to the decomposition of A1 2 Oz by electric current

2A1 2 Oz \u003d 4A1 + 3O 2 (950 0 C, A1Fz ∙ 3NaF, electric current)

Liquid aluminum is released at the cathode:

A1 3+ + 3-\u003d Al 0

Oxygen is released at the anode.

Physical properties

Lightweight, silvery-white, ductile metal, conducts electricity and heat well.

In air, aluminum is covered with the thinnest (0.00001 mm), but very dense oxide film, which protects the metal from further oxidation and gives it a matte appearance.

Aluminum is easily drawn into wire and rolled into thin sheets. Aluminum foil (0.005 mm thick) is used in the food and pharmaceutical industries for packaging products and preparations.

Chemical properties

Aluminum is a very active metal, slightly inferior in activity to the elements of the beginning of the period - sodium and magnesium.

1. aluminum easily combines with oxygen at room temperature, while an oxide film forms on the aluminum surface (layer A1 2 O 3). This film is very thin (≈ 10 -5 mm), but strong. It protects aluminum from further oxidation and is therefore called a protective film.

4Al + 3O 2 \u003d 2Al 2 O 3

2.in interaction with halogens, halides are formed:

with chlorine and bromine, interaction occurs already at ordinary temperature, with iodine and sulfur - when heated.

2Al + 3Cl 2 \u003d 2AlCl 3

2Al + 3S \u003d Al 2 S 3

3. At very high temperatures, aluminum also combines directly with nitrogen and carbon.

2Al + N 2 \u003d 2AlN aluminum nitride

4Al + 3C \u003d Al 4 C 3 aluminum carbide

Aluminum does not interact with hydrogen.

4. aluminum is quite resistant to water. But if the protective effect of the oxide film is removed mechanically or by amalgamation, then an energetic reaction occurs:

2Al + 6H 2 O \u003d 2Al (OH) 3 + 3H 2

5.interaction of aluminum with acids

With split. with acids (HCl, H 2 SO 4), aluminum interacts with the formation of hydrogen.

2Al + 6HCl \u003d 2AlCl 3 + 3H 2

In the cold, aluminum does not interact with concentrated sulfuric and nitric acid.

Interacts with conc. sulfuric acid when heated

8Al + 15H 2 SO 4 \u003d 4Al 2 (SO 4) 3 + 3H 2 S + 12H 2 O

Aluminum reacts with dilute nitric acid to form NO

Al + 4HNO 3 \u003d Al (NO 3) 3 + NO + 2H 2 O

6.interaction of aluminum with alkalis

Aluminum, like other metals that form amphoteric oxides and hydroxides, interact with alkali solutions.

Aluminum under normal conditions, as already noted, is covered with a protective film A1 2 O 3. Under the action of aqueous solutions of alkalis on aluminum, the layer of aluminum oxide A1 2 O 3 dissolves, and aluminates are formed - salts containing aluminum in the anion:

A1 2 O 3 + 2NaOH + 3H 2 O \u003d 2Na

Aluminum, devoid of a protective film, interacts with water, displacing hydrogen from it

2Al + 6H 2 O \u003d 2Al (OH) 3 + 3H 2

The resulting aluminum hydroxide reacts with excess alkali to form tetrahydroxoaluminate

Al (OH) 3 + NaOH \u003d Na

The overall equation for the dissolution of aluminum in an aqueous solution of alkali:

2Al + 2NaOH + 6Н 2 О \u003d 2Na + 3H 2

Aluminum oxide A1 2 O 3

White solid, insoluble in water, melting point 2050 ° C.

Natural A1 2 O 3 - corundum mineral. Transparent colored crystals of corundum - red ruby \u200b\u200b- contains an admixture of chromium - and blue sapphire - an admixture of titanium and iron - precious stones. They are also obtained artificially and used for technical purposes, for example, for the manufacture of parts of precision instruments, stones in watches, etc.

Chemical properties

Aluminum oxide exhibits amphoteric properties

1.interaction with acids

A1 2 O 3 + 6HCl \u003d 2AlCl 3 + 3H 2 O

2.interaction with alkalis

A1 2 O 3 + 2NaOH - 2NaAlO 2 + H 2 O

Al 2 O 3 + 2NaOH + 5H 2 O \u003d 2Na

3. When a mixture of the corresponding metal oxide with aluminum powder is heated, a violent reaction occurs, leading to the release of the free metal oxide from the taken oxide. The reduction method with Al (alumothermy) is often used to obtain a number of elements (Cr, Mn, V, W, etc.) in a free state

2A1 + WO 3 \u003d A1 2 Oz + W

4.interaction with salts having a highly alkaline medium due to hydrolysis

Al 2 O 3 + Na 2 CO 3 \u003d 2 NaAlO 2 + CO 2

Aluminum hydroxide A1 (OH) 3

A1 (OH) 3 is a voluminous gelatinous white precipitate, practically insoluble in water, but easily soluble in acids and strong alkalis. It therefore has an amphoteric character.

Aluminum hydroxide is obtained by the reaction of the exchange of soluble aluminum salts with alkalis

AlCl 3 + 3NaOH \u003d Al (OH) 3 ↓ + 3NaCl

Al 3+ + 3OH - \u003d Al (OH) 3 ↓

This reaction can be used as a qualitative one for the Al 3+ ion

Chemical properties

1.interaction with acids

Al (OH) 3 + 3HCl \u003d 2AlCl 3 + 3H 2 O

2.in interaction with strong alkalis, the corresponding aluminates are formed:

NaOH + A1 (OH) s \u003d Na

3.thermal decomposition

2Al (OH) 3 \u003d Al 2 O 3 + 3H 2 O

Aluminum saltsundergo cation hydrolysis, acidic medium (pH< 7)

Al 3+ + H + OH - ↔ AlOH 2+ + H +

Al (NO 3) 3 + H 2 O↔ AlOH (NO 3) 2 + HNO 3

Soluble salts of aluminum and weak acids undergo complete (irreversible hydrolysis)

Al 2 S 3 + 3H 2 O \u003d 2Al (OH) 3 + 3H 2 S

Application in medicine and the national economy of aluminum and its compounds.

The lightness of aluminum and its alloys and high resistance to air and water determine their use in mechanical engineering, aircraft construction. As a pure metal, aluminum is used to make electrical wires.

Aluminum foil (0.005 mm thick) is used in the food and pharmaceutical industries for packaging products and preparations.

Aluminum oxide Al 2 O 3 - is part of some antacids (for example, Almagel), is used with increased acidity of gastric juice.

KAl (SO 4) 3 12H 2 O - potassium alum is used in medicine for the treatment of skin diseases, as a hemostatic agent. And also used as a tanning agent in the leather industry.

(CH 3 COO) 3 Al - Liquid Burov - 8% solution of aluminum acetate has an astringent and anti-inflammatory effect, in high concentrations it has moderate antiseptic properties. It is used diluted for rinsing, lotions, for inflammatory diseases of the skin and mucous membranes.

AlCl 3 - used as a catalyst in organic synthesis.

Al 2 (SO 4) 3 · 18 H 2 0 - used for water purification.

Control questions for consolidation:

1. What is the highest valence, the oxidation state of group III A elements. Explain in terms of atomic structure.

2. Name the most important boron compounds. What is a qualitative borate ion reaction?

3. What are the chemical properties of aluminum oxide and hydroxide?

Mandatory

Pustovalova L.M., Nikanorova I.E. . Inorganic chemistry. Rostov-on-Don. Phoenix. 2005.-352s. ch. 2.1 sec 283-294

Additional

1. Akhmetov NS General and inorganic chemistry. M.: Higher school, 2009.- 368s.

2. Glinka N.L. General chemistry. KnoRus, 2009.-436 p.

3. Erokhin Yu.M. Chemistry. Textbook for stud. Sred professional image.-M .: Academy, 2006.- 384s.

Electronic resources

1. Open chemistry: a complete interactive chemistry course for students in schools, lyceums, gymnasiums, colleges, studios. technical universities: version 2.5-M .: Fizikon, 2006. Electronic optical disk CD-ROM

2. .1C: Tutor - Chemistry, for applicants, high school students and teachers, JSC "1C", 1998-2005. Electronic optical disc CD-ROM

3. Chemistry. Fundamentals of Theoretical Chemistry. [Electronic resource]. URL: http://chemistry.narod.ru/himiya/default.html

4. Electronic library of teaching materials in chemistry [Electronic resource]. URL: http://www.chem.msu.su/rus/elibrary/

In the form of the most common alumina, its chemical formula is AL2O3. In appearance, these are crystals without color, which begin to melt at a temperature of 2044 ° C, and when they reach a mark of 3530 ° C, they boil.

In the natural environment, the only stable modification of the substance is corundum, which has a density of 3.99 g / cm3. It is a very hard specimen and belongs to the ninth level of the Mohs chart. The value of the refractive index is: for an ordinary ray - 1.765, and 1.759 for an extraordinary one. In a natural environment, aluminum oxide often contains various metal oxides, therefore, the corundum mineral can acquire different shades of its color. For example, these are sapphires, rubies and other precious stones. In this form, aluminum oxide can be obtained by laboratory-chemical method. To do this, use metastable forms of A12O3 and decompose them thermally. Also, as a source of aluminum oxide production by the laboratory method,

The standard modification of the compound is a tetragonic crystal lattice containing about 1-2% water in its composition. It is possible to obtain alumina oxide, amorphous in its structure, alumogel, for which a gel-like solution of AL (OH) 3 is dehydrated and a substance is obtained in the form of a porous transparent mass.

Aluminum oxide is completely insoluble in water, but can dissolve well in cryolite heated to high temperatures. The substance is amphoteric. A characteristic property of synthesized aluminum oxide is the inverse dependence of the temperature of its formation and chemical activity. Both artificial (that is, obtained at a temperature of more than 1200 ° C) and natural corundum in an ordinary environment show almost one hundred percent chemical inertness and a complete absence of hygroscopicity.

Oxide begins to actively develop at temperatures of about 1000 ° C, when it begins to interact intensively with substances such as various alkalis, carbonates. Aluminates are formed during this interaction. More slowly, the compound reacts with SiO2, as well as various acidic slags. As a result of these interactions, aluminosilicates are obtained.

Alumogels and aluminum oxide, which are obtained by firing any of the aluminum hydroxides at a temperature of at least 550 ° C, have a very high hygroscopicity, perfectly enter into and actively interact with acid and alkaline solutions.

As a rule, bauxites, alunites, and nephelines are used as raw materials for the production of aluminum oxide. When the content of the considered substance in them is more than 6-7%, production is carried out by the main method - the Bayer method, and with a lower content of the substance, the method of sintering ore with lime or soda is used. The Bayer method is the processing of crushed rock, then bauxite is treated with alkaline solutions at a temperature of 225-250 ° C. The sodium aluminate composition thus obtained is diluted with an aqueous solution and filtered. In the filtration process, the sludge containing alumina, the properties of which correspond to the standard, are subjected to decomposition in centrifuges. This technology makes it possible to obtain a 50% yield of the substance. In addition, the application of this method allows you to save for use in subsequent bauxite leaching operations.

Typically, synthetic aluminum oxide is used as an intermediate material for pure aluminum production. In industry, it is used as a raw material for the manufacture of refractory materials, abrasive and ceramic cutting tools. Modern technologies are actively using single crystals of aluminum oxide in the manufacture of watches and jewelry.

4.9.1; 4.10.1

4.4.1; 4.8.1; 4.9.1; 4.11.1

4.4.1; 4.8.1; 4.9.1

4.9.1; 4.10.1

5. The limitation of the validity period has been removed according to protocol N 5-94 of the Interstate Council for Standardization, Metrology and Certification (IUS 11-12-94)

6. EDITION (March 2004) with Amendment No. 1, approved in November 1988 (IUS 2-89)

This standard applies to active alumina-modification in the form of cylindrical granules, used as a carrier for catalysts, catalysts, raw materials for the production of mixed catalysts, desiccants in various processes of chemical, petrochemical industries, etc.

Formula -AlO.

Molecular weight (according to the international atomic weights of 1971) - 101.96.

1. TECHNICAL REQUIREMENTS

1.1. Active alumina must be manufactured in accordance with the requirements of this standard for the technological regulations approved in the prescribed manner.

1.2. Active aluminum oxide, depending on the field of application, is produced in three grades - AOA-1, AOA-2 and AOA-3. Grades AOA-1 and AOA-2 are used as a carrier of catalysts, catalysts and desiccants, grade AOA-3 is used as a raw material for the production of mixed catalysts.

1.3. According to the main indicators, active aluminum oxide must comply with the standards specified in the table.


Indicator name	Norm for the brand
	AOA-1 OKP 21 6321 0100	AOA-2 OKP 21 6321 0200	AOA-3 OKP 21 6321 0300
1. Appearance	White cylindrical granules, creamy shade allowed
2. Sizes of granules, mm:

length, not more			Not standardized
3. Bulk density, g / dm			Not more than 650
4. Abrasion resistance,%, not less
5. Specific surface, m / g	Not less than 200		Not less than 200
6. Mass fraction of losses on ignition,%, no more
7. Mass fraction of iron,%, no more
8. Mass fraction of sodium,%, no more
9. Mass fraction of dust and fines less than 2.0 mm in size,%, no more

1.2, 1.3. (Modified edition, Amendment N 1).

2. SAFETY REQUIREMENTS

2.1. Active aluminum oxide is not flammable, not explosive. Irritating to mucous membranes of the upper respiratory tract, mouth and eyes.

Long-term inhalation of active alumina can cause darkening of the lungs.

2.2. The maximum permissible concentration of active aluminum oxide in the air of the working area is 2 mg / m.

According to the degree of impact on the human body, active aluminum oxide belongs to the 3rd hazard class according to GOST 12.1.005.

2.3. When working with active alumina, safety precautions should be taken and personal protective equipment should be used in accordance with established inspection rules.

2.4. Premises where work is carried out with active alumina must be equipped with supply and exhaust ventilation, which ensures the mass concentration of active alumina in the air of the working area within the limits not exceeding the maximum permissible concentration.

(Modified edition, Amendment N 1).

2.5. Cleaning of working premises from dust should be carried out using a wet method or pneumatic (stationary or mobile vacuum cleaner units).

Dust removal of machinery and equipment should be carried out using a hose connected to the vacuum line.

3. RULES OF ACCEPTANCE

3.1. Active alumina is taken in batches. A batch is considered to be the quantity of a product that is homogeneous in its quality indicators, accompanied by one quality document. The mass of the batch should be no more than 4 tons.

Each batch must be accompanied by a quality document, which must contain:

the name of the manufacturer or its trademark;

product name and brand;

batch number and date of manufacture;

the number of product units in the batch;

gross and net weight;

test results or confirmation of compliance with the requirements of this standard;

technical control stamp;

designation of this standard.

3.2. To check the quality of active alumina for compliance with its parameters with the requirements of this standard, a sample is taken from 10% of packaging units, but not less than three packaging units.

(Modified edition, Amendment N 1).

3.3. If unsatisfactory analysis results are obtained for at least one of the indicators, a second test is carried out on a doubled sample. The retest results apply to the entire batch.

4. CONTROL METHODS

General instructions for conducting analyzes - according to GOST 27025.

(Modified edition, Amendment N 1).

4.1. Sample selection

4.1.1. Spot samples from the packaged product are taken with a probe made of stainless steel (Fig. 1), immersing it to the depths of the product, or by any similar means.

Damn 1

The mass of the selected spot sample must be at least 200 g.

(Modified edition, Amendment N 1).

4.1.2. The selected point samples are combined together, mixed thoroughly, and a combined sample is obtained. Reduce the combined sample by quartering until an average sample weighing at least 0.5 kg is obtained.

4.1.3. The average sample of active alumina is divided into two parts, placed in two clean, dry jars and sealed with a lid or ground stopper.

Banks seal and stick paper labels with the following symbols:

product name and brand;

the name of the manufacturer or its trademark;

sampling dates;

batch numbers and weights;

designations of this standard.

One can is transferred to the laboratory for control, the other is stored for 6 months in case of disagreements in the quality assessment.

4.2. The appearance of the product is determined visually

4.3. Determination of granule size

4.3.1. Devices

Vernier caliper in accordance with GOST 166.

4.3.2. Testing

20 whole granules are taken from the average sample, the diameter of each granule is measured with a caliper with an accuracy of the first decimal place.

The sizes of each granule must be within the limits specified in the technical requirements.

It is allowed to determine the size of granules using a dial indicator in accordance with GOST 577.

(Modified edition, Amendment N 1).

4.4. Determination of bulk density

4.4.1. Equipment

General purpose scales in accordance with GOST 24104 *, 3rd class of accuracy with weighing range from 50 to 200 g.
________________
* Since July 1, 2002, GOST 24104-2001 has been put into effect (hereinafter).

Measuring cylinder 1-100 in accordance with GOST 1770.

Drying cabinet of any type, providing heating to a temperature of (110 ± 10) ° С.

Desiccator according to GOST 25336.

4.4.2. Testing

100.00 g of active aluminum oxide crushed to 4-6 mm (using nippers) is dried in an oven at a temperature of (110 ± 10) ° С for 2 hours and cooled in a desiccator to room temperature. The cooled active alumina is placed in a pre-weighed measuring cylinder, compacted by tapping the cylinder against a wooden board or on a vibrator designed by GrozNII, type B.

The cylinder is filled to the mark, the contents are compacted until the volume of active alumina is constant and reaches 100 cm3, after which the cylinder with active alumina is weighed.

4.4.3. Processing results

Bulk density () in g / dm3 is calculated by the formula

where is the mass of the cylinder with active aluminum oxide, g;

Empty cylinder weight, g;

- the volume of active aluminum oxide, see.

The arithmetic mean of the results of two parallel determinations is taken as the measurement result, the absolute discrepancy between which should not exceed 20 g / dm3. The admissible total measurement error is ± 10 g / dm at a confidence level of 0.95.

In case of disagreement in the assessment of the bulk density, the method of shaking active alumina by tapping the cylinder on a wooden board should be used.

4.4.1-4.4.3. (Modified edition, Amendment N 1).

4.5. Determination of abrasion strength

Abrasion strength is determined according to GOST 16188.

Before testing, the sample is crushed using nippers or scissors to granules with a size of 4-6 mm and sieved on a No. 40 sieve type I. Then the sample is dried for 2 hours in a closed drying cabinet at a temperature of (110 ± 10) ° C. The bulk density is determined according to this standard.

4.6. (Deleted, Rev. N 1).

4.7. The specific surface area is determined according to GOST 23401.

A 15-20 g sample is taken from the average sample, ground in a mortar, sifted manually on a sieve with a 04-20 mesh in accordance with GOST 6613 and a weighed portion for testing weighing 0.1-0.2 g is taken.

Before measuring the specific surface area, the sample must be preliminarily dried at a temperature of 150-170 ° C to constant weight, if it is not subjected to the training process.

When carrying out daily calibration of the detector, calibration of the metering valve is not necessary.

It is allowed to carry out the determination on the "Tsvet-211", "Tsvet-213" or "Tsvet-215" sorbtometer.

4.8. Determination of the mass fraction of losses on ignition

4.8.1. Equipment

GOST 24104

Porcelain crucible in accordance with GOST 9147.

Desiccator according to GOST 25336.

An electric furnace of any type, providing heating to a temperature of (800 ± 10) ° С.

(Modified edition, Amendment N 1).

4.8.2. Analysis

About 2.0000 g of active alumina is placed in a crucible, previously calcined at a temperature of (800 ± 10) ° C to constant weight, cooled in a desiccator and weighed. The crucible with the contents is dried at a temperature of (110 ± 10) ° С to constant weight, weighed and then calcined at a temperature of (800 ± 10) ° С to constant weight, carrying out a gradual increase in temperature.

4.8.3. Processing results

The mass fraction of losses on ignition () in percent is calculated by the formula

where is the mass of the dried active aluminum oxide, g;

Mass of calcined active aluminum oxide, g.

The arithmetic mean of the results of two parallel determinations is taken as the measurement result, the absolute discrepancy between which should not exceed 0.2%. The permissible total measurement error is ± 0.1% at a confidence level of 0.95.

(Modified edition, Amendment N 1).

4.9. Iron mass fraction measurement

The method is based on photometric measurement of the intensity of the yellow color of the complex formed by the interaction of iron (III) with sulfosalicylic acid in an ammonia environment.

4.9.1. Equipment, reagents, solutions

Laboratory scales for general use in accordance with GOST 24104, 2nd class of accuracy with the maximum weighing limit of 200 g.

Electric tile with a power of 800 W in accordance with GOST 14919 or another type of specified power.

Photoelectric colorimeter KFK-2 or other type.

Burette 7-2-10 or 6-2-5 in accordance with GOST 29251.

Beaker 50 in accordance with GOST 1770.

Flasks 2-50-2, 2-100-2, 2-1000-2 in accordance with GOST 1770.

Pipettes 2-2-5, 2-2-20 in accordance with GOST 29227.

Glass V-1-250 TCS in accordance with GOST 25336.

Watch glass.

Ammonia water according to GOST 3760.

Distilled water in accordance with GOST 6709.

Alarm clock according to GOST 3145 or other type.

Sulfuric acid according to GOST 4204, solution of concentration (HSO) \u003d 0.01 mol / dm (0.01 N) and solution 1: 2.

Sulfosalicylic acid according to GOST 4478, a solution with a mass fraction of 20%.

Standard solution of iron (III) mass concentration 1 mg / cm (solution A); prepared according to GOST 4212.

When using iron-ammonium alum of "pure" qualification, it is necessary to first determine the mass fraction of the basic substance by gravimetric or complexometric method.

To construct a calibration graph with a corresponding dilution of solution A with sulfuric acid concentration of 0.01 mol / dm3, prepare solution B of mass concentration 0.02 mg / cm3 of iron (III

4.9.2. Building a calibration graph

Into a number of volumetric flasks with a capacity of 50 ml, 0.5; 1.0; 2.0; 3.0; 4.0 ml of standard solution B. Add 5 ml of sulfosalicylic acid, 5 ml of aqueous ammonia to each flask, add water to the mark and mix. After 30 min, the optical density of the solution is measured on a photoelectric colorimeter at a wavelength of 410 nm in a cuvette with a 50 mm light-absorbing layer.

The reference solution contains all reagents except the standard iron solution.

Based on the data obtained, a calibration graph of the dependence of the optical density of solutions on the mass of iron in milligrams is built.

4.9.3. Preparation for analysis

About 2.0000 g of finely ground active alumina is placed in a beaker, moistened with water, 20 ml of a 1: 2 sulfuric acid solution is added and the sample is dissolved at low boiling. Remove the glass from the hotplate, carefully add 20 ml of water, transfer it to a 100 ml volumetric flask, cool to room temperature, add water to the mark and mix.

4.9.4. Analysis

5 ml of the solution prepared as described in clause 4.9.3 is placed in a flask with a capacity of 50 ml, 5 ml of sulfosalicylic acid solution, 5 ml of aqueous ammonia, add water to the mark and mix.

Measure the optical density under the same conditions as when constructing a calibration graph.

The mass of iron is found from the calibration graph.

4.9.5. Processing results

The mass fraction of iron () in percent is calculated by the formula

where is the mass of iron found from the calibration graph, mg;

Sample weight, g.

The arithmetic mean of the results of two parallel determinations is taken as the result of the analysis, the absolute discrepancy between which should not exceed 0.005%. The admissible total error of the analysis result is ± 0.003% at a confidence level of 0.95.

4.10. Determination of the mass fraction of sodium

The method is based on a comparison of the radiation intensity of sodium resonance lines in the spectrum of a propane-air flame obtained by spraying sample and standard solutions into it.

4.10.1. Equipment, reagents, solutions

Flame photometer Zeiss type III (manufactured by the German Democratic Republic) with a set of interference filters for sodium or a device of any other brand with a sensitivity of at least 0.5 μg / cm for sodium.
Standard sodium solution of mass concentration 0.1 mg / cm; prepared as follows: 0.2542 g of sodium chloride, pre-calcined to constant weight at a temperature of 500 ° C, is placed in a flask with a capacity of 1 dm 3, dissolved in water, added to the mark with water and stirred.

The solution and water for preparing the stock solution are stored in a polyethylene container.

Sodium chloride according to GOST 4233.

Distilled water in accordance with GOST 6709.

The background solution is distilled water.

4.10.2. Photometry conditions

The preparation of the device for operation should be carried out according to the technical description and the operating instructions for the flame photometer.

4.10.3. Building a calibration graph

In a row of volumetric flasks with a capacity of 100 ml using a burette, place 1.0; 2.0; 3.0; 4.0; 5.0; 6.0; 7.0; 8.0; 9.0; 10.0 ml of sodium standard solution, add water to the mark and mix. The device is prepared for analysis according to the instructions attached to it.

After preparation of the device, the water taken for the preparation of standard solutions is photometric to determine the mass fraction of sodium impurities, as well as standard solutions in increasing order of the mass concentration of sodium, spraying water after each measurement. After that, the standard solutions are photometric in reverse order, starting with the highest concentration. Each point of the calibration graph is plotted according to the arithmetic mean of five to six measurements of the newly prepared series of standard solutions, taking into account as a correction the readout from the galvanometer during photometry of water. Based on the data obtained, a calibration graph of the dependence of the readings of the galvanometer on the mass concentration of sodium in micrograms per cubic centimeter is plotted.

4.10.4. Analysis

After preparing the device for analysis, a background solution (distilled water) is sprayed into the burner flame and the test solution prepared in accordance with clause 4.9.3 is photometric according to the instructions and the device. According to the indications of the galvanometer and the calibration graph, the mass concentration of sodium is found.

4.10.5. Processing results

The mass fraction of sodium () in percent is calculated by the formula

where is the mass concentration of sodium found from the calibration graph, μg / cm;

Weight of a sample of active aluminum oxide, g.

For the analysis result, the arithmetic mean of the results of two parallel determinations is taken, the absolute discrepancy between which should not exceed 0.001%. The admissible total error of the analysis result is ± 0.0006% at a confidence level of 0.95.

4.9-4.10.5. (Modified edition, Amendment N 1).

4.11. Determination of the mass fraction of dust and fines less than 2 mm in size

4.11.1. Devices

Sieve classifier with a set of stamped sieves, type RKF-IV.

Laboratory scales for general use in accordance with GOST 24104, 2nd class of accuracy with the maximum weighing limit of 200 g.

Sieve 40 type I.

Alarm clock - according to GOST 3145-84 or other type.

(Modified edition, Amendment N 1).

4.11.2. Testing

About 100.0 g of active alumina is placed on a 2 mm sieve. A pallet is installed below. The top of the sieve is closed with a lid. Sieving time 2 min. The vibration amplitude is 1.2-1.5 mm.

In the absence of a lattice classifier, sieving is carried out on a sieve. Sieving time 2-3 min with 100-120 shakes per 1 min.

4.11.3. Processing results

The mass fraction of dust and fines 2 mm in size () as a percentage is calculated by the formula

where is the weight of the sample, g;

- mass of particles on the pallet, g.

The arithmetic mean of the results of two parallel determinations is taken as the test result, the allowable discrepancies between which should not exceed 0.05% with a confidence level of 0.95.

5. PACKAGING, LABELING, TRANSPORTATION AND STORAGE

GOST 13950 of any design, polyethylene barrels for catalysts (with a capacity of 50, 60, 100, 120 dm 3).

By agreement with the consumer, it is allowed to pack the product in barrels in accordance with GOST 13950 type I and flasks in accordance with GOST 5799 of any design (with a capacity of 40 dm3).

The inner surface of the metal container must not contain traces of corrosion.

5.2. Marking

Transport marking - in accordance with GOST 14192 with the application of basic, additional, information labels and a manipulation sign "Hermetic packaging".

A paper tag No. 2 is attached to each packaging unit, including:

the name of the manufacturer and its trademark;

product name;

date of manufacture;

batch number;

designation of this standard;

gross-net weight.

The marking can be applied directly to the container using a stencil or stamp with indelible paint.

5.3. Transportation

Active aluminum oxide is transported by all modes of transport, except for air, in covered vehicles in accordance with the transportation rules in force for this type of transport, during transportation by rail - by wagonload and small shipments.

5.4. Storage

Active alumina should be stored in dry rooms.

6. MANUFACTURER'S WARRANTIES

6.1. The manufacturer guarantees the compliance of active alumina with the requirements of this standard, subject to the conditions of transportation and storage.

6.2. The guaranteed shelf life of aluminum oxide is 5 years from the date of manufacture of the product.

Electronic text of the document
prepared by Kodeks CJSC and verified by:
official publication
Moscow: IPK Standards Publishing House, 2004

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