The use of selected natural raw materials is... Concept and classification of raw materials and supplies
Each enterprise has a large number of various raw materials and materials, therefore their classification cannot be limited to the system of accounts synthetic accounting. A more detailed classification into groups and subgroups according to technical properties or signs. The number of groups and subgroups is determined based on the range of materials and the nature of the products being manufactured. However, they should be based on the grouping adopted in statistical reporting about the movement of materials.
Within each group, materials are divided by name, grade, and size.
Each type of material is assigned a nomenclature number (code), which is included in the list called nomenclature material assets, and is also indicated on all primary documents on the movement of materials.
To reduce the accounting nomenclature of materials and simplify accounting, materials that are homogeneous and similar in their properties can be combined into one nomenclature number. The codes are constructed in such a way that the group of materials, as well as their other characteristics, can be determined by the nomenclature number.
The nomenclature-price tag is a systematic reference book covering all material assets located in the enterprise. When developing it, you should pay attention Special attention on the correctness of the names of material assets and units of measurement.
The nomenclature numbers assigned to materials must be indicated in all documents on the movement of raw materials and materials, on material labels and warehouse registration cards. This facilitates subsequent processing of documents and prevents errors during the posting or write-off of materials and raw materials.
As noted, the variety of raw materials and materials depends on the type of production. During the production process, materials are used in different ways. Some of them are completely consumed in the production process (raw materials and materials), others change only their shape and size (lubricants, paints), others are included in products without any external changes(spare parts). Materials belong to the category of disposable production elements: their cost is immediately included in the cost of products (works, services).
Depending on the role played by various production inventories in the production process, they are divided into the following groups: raw materials and basic materials, auxiliary materials, purchased semi-finished products and components, waste (returnable), fuel, packaging and packaging materials, spare parts, inventory and household supplies.
Raw materials and basic materials are objects of labor from which a product is made and which form the material (material) basis of the product. Raw materials are the products of agriculture and the mining industry (grain, cotton, livestock, milk, etc.), and materials are the products of the manufacturing industry (flour, fabric, sugar, etc.).
Auxiliary materials are used to influence raw materials and basic materials, giving the product certain consumer properties, or for servicing and caring for tools and facilitating the production process (spices in sausage production, lubricants, cleaning materials, etc.).
It should be borne in mind that the division of materials into main and auxiliary is conditional and often depends only on the amount of material used for production various types products.
Purchased semi-finished products are raw materials and materials that have undergone certain stages of processing, but are not yet finished products. In the manufacture of products they play the same role as the main materials, i.e. constitute their material basis.
Components are purchased to complete manufactured products.
Returnable production waste is the remains of raw materials and materials generated during their processing into finished products, wholly or partially lost consumer properties raw materials and materials (sawdust, shavings, etc.).
From the group of auxiliary materials, fuel, containers and packaging materials, and spare parts are separately distinguished due to the nature of their use.
Fuel is divided into technological (for technological purposes), motor (fuel) and economic (for heating).
Containers and packaging materials - items used for packaging, transportation, storage various materials and products (bags, boxes, boxes). Spare parts are used to repair and replace worn-out parts of machines and equipment. Inventory and household supplies are part of the organization’s inventory, used as labor tools for no more than 12 months or the normal operating cycle, if it exceeds 12 months (inventory, tools, etc.)
In addition, materials are classified according to technical properties and divided into groups: ferrous and non-ferrous metals, rolled products, pipes, etc.
The materials include more than general group assets, which is called inventories (MPI) and includes the following elements:
- - used as raw materials in the production of products (performance of work, provision of services);
- - intended for sale (goods and finished products);
- - used for the management needs of the organization.
Unfinished products, called work in progress, do not belong to inventories.
Thus, it should be noted that the classification cannot be limited to the system of synthetic accounting accounts. All materials are classified according to technical properties and characteristics, as well as their role in the production process.
Classification of raw materials
Concept of raw materials. Types and classification of raw materials
Simplified technological scheme chemical production can be represented as:
IN chemical production At various stages of processing, the following material objects can be distinguished: the original substance or the raw material itself, intermediate products (semi-products), by-products and waste.
Raw materials are natural or industrial materials that are used in production to produce industrial products.
Raw materials are the main element of the technological process, which largely determines the efficiency of the process and the choice of technology.
RAW MATERIALS are raw materials for which labor has been expended to obtain and deliver them, and which therefore have value. Several types of raw materials are often used.
BURGE – a mixture consisting of several types of solid materials.
PULP – a semi-liquid mixture of several materials
SLUDGE – a viscous, low-flow mixture of several materials
INTERMEDIATE PRODUCT (intermediate product, semi-finished product) – a product obtained at any intermediate stage.
WASTE of production – end products generated along with the target.
BY-PRODUCTS – used production waste
WASTE – unused production waste.
Intermediate refers to raw materials that have been processed at one or more stages of production, but not consumed as a finished target product. It can be used at subsequent stages of production. For example, coal→ coke oven gas→ hydrogen→ ammonia.
Side effects a product is a substance formed during the processing of raw materials, along with the target product, but is not the goal of this process. For example, ammonium nitrate, chalk in the production of nitroammophoska.
Waste production are the remains of raw materials, materials, intermediate products formed in production and wholly or partially lost their qualities. For example, phosphogypsum in the production of superphosphate.
Often finished product from one production serves raw materials or intermediate products for another. For example, synthetic ammonia and nitric acid (finished products) can serve as raw materials for the production of ammonium nitrate, and cast iron for steel smelting.
Chemical raw materials are usually divided into:
– primary (extracted from a natural source;
– secondary (intermediate and by-products);
– natural;
– artificial (obtained as a result of processing natural raw materials).
All chemical raw materials divided into groups By origin , chemical composition , state of aggregation , purpose .
In my own way origin raw materials are divided into three groups:
- mineral;
- vegetable;
- animal .
!!! Mineral raw materials called minerals mined from the depths of the earth .
Mineral raw materials are divided into:
- ore;
- nonmetallic;
- fuel .
2.1.1.1. Ore mineral raw materials
Ore raw materials or ore serve to obtain from it metals . Metals in ore are presented mainly in the form oxides (Mt n O m) or sulfides (Mt n S m).
Ore non-ferrous metals quite often contain connection of several metals . It can be lead sulfides , copper , zinc , silver .
Such ore called polymetallic ores.
2.1.1.2. Non-metallic mineral raw materials
Non-metallic mineral raw materials- This rocks or minerals which are used for:
- production of non-metals - sulfur , chlorine , phosphorus ;
- others chemical products - fertilizers , soda , alkalis , acids .
Non-metallic minerals conditionally divided into several groups.
1. Construction Materials - it's mineral raw materials, used in construction ( gravel , sand , clay , building stones , brick , cement ).
2. Industrial raw materials - minerals , used without chemical processing V various industries industry ( graphite , mica , asbestos ).
3. Chemical mineral raw materials - minerals , which are exposed chemical processing (sulfur , saltpeter , phosphate rock , cookery And potassium salt ).
4. Precious, semi-precious and ornamental raw materials: diamonds , emeralds , rubies , malachite , jasper , marble .
2.1.1.3. Combustible mineral raw materials
Combustible mineral raw materials - these are fossils that can serve as fuel (stone And brown coal , oil shale , oil, natural gas ).
Fuel is a name given to natural or artificial combustible organic materials that serve as a source of thermal energy and raw material for the chemical industry.
By state of aggregation all types of fuel are divided into solid, liquid and gaseous.
2.1.1.4. Raw materials of plant and animal origin
Raw materials of plant and animal origin is product Agriculture (livestock farming , agriculture , crop production ), fish And forestry .
In my own way purpose these types raw materials are divided into food And technical raw materials.
TO food raw materials include animal And vegetable raw materials processed into Food.
Technical raw materials are called those products, which are for food purposes unsuitable, but after mechanical And chemical treatments are used in industry And everyday life (tree , cotton , linen , leather , wool , fur ).
Subdivision raw materials animal And vegetable origin on food And technical enough conditionally. Food raw materials often processed into technical products :
- potato and other products are processed into ethanol ;
Some animals And vegetable oils are processed into soap And cosmetical tools .
The value of raw materials depends on the level of technological development. For example, potassium chloride was a used waste product in the 19th century in the extraction of sodium chloride from sylvinite. In present day potassium chloride is the starting material in mineral fertilizers. A number of general requirements are imposed on substances used as chemical raw materials.
Raw materials for chemical production must provide:
– few stages production process;
– state of aggregation of the system, requiring minimal energy expenditure to create
– optimal conditions for the process;
– minimal dissipation of supplied energy;
– possibly lower process parameters;
– maximum content of the target product in the reaction mixture.
To meet these requirements, raw materials (especially minerals extracted from natural environment) are subjected to PRELIMINARY PREPARATION.
Basic operations for preparing raw materials:
Classification(separation of homogeneous bulk materials into fractions (classes) according to the sizes of their constituent particles).
Dehydration the material is achieved by the methods of draining, settling (liquid system) and drying.
Drying is the process of removing moisture or other liquid from solid materials by evaporating it and removing the resulting vapor.
Enrichment is the process of separating the useful part of the raw material from waste rock (ballast) in order to increase the concentration of the useful component. As a result of enrichment, the raw material is divided into a concentrate of the useful component and tailings with a predominance of waste rock.
The choice of enrichment method depends on state of aggregation and differences in the properties of raw material components. For solid most often used mechanical enrichment methods:
– dispersion (rattling),
– gravitational separation,
– electromagnetic and electrostatic separation,
– flotation (special physical and chemical method).
Chemical methods enrichment are based on the use of reagents that selectively dissolve one of the substances that make up the mixture, or form compounds with one of the substances that are easily separated from others during melting, evaporation, or precipitation of the solution. Example: roasting minerals to decompose carbonates, removing crystallization moisture, burning organic impurities.
Every industry industrial production have their own characteristics. Chemists also have them. industry. One of them is the material intensity of this industry. To obtain a certain volume of chemical products, raw materials are required that are many times greater than the output volume of manufactured objects. That is why high-quality raw materials for the chemical industry are one of the most important factors her successful economic development. After all, the cost of production directly depends on the type of raw materials, their quality, cost and methods of obtaining and transporting them.
KINDS
In chemistry, raw materials mean the starting substances used to make products. In this case, a distinction is made between raw materials themselves (raw material) and technological raw materials (which have gone through some stages of processing). An example of a raw material is petroleum used to produce gasoline. An example of a technological raw material is shredded wood, which can subsequently be used to manufacture corresponding products.
Also, as source material for chem. industry sometimes uses so-called intermediates. These materials are the result of multi-stage processing, and act as a starting material for the manufacture of other products. Sometimes the same substance can act in one case as a useful chemical product, and in another as a raw material for the production of other products.
Another important source of raw materials can be chemical waste. technological processes. As a rule, there are a lot of them in the chemical industry. And any way to use this waste usefully, and even more so, as a raw material for products, not only helps to save on its production, but also increases its environmental safety for the environment.
In addition, there is also a division of raw materials into mineral and artificial, plant and animal, etc.
Mineral raw materials are in great demand in various sectors of the chemical industry. It includes ore and non-metallic raw materials, as well as water, air and fossil fuels.
WHAT SHOULD BE CONSIDERED WHEN SELECTING RAW MATERIALS
The correct selection of raw materials is the most important stage in any chemical production, determining not only the quality of the final product, but also the economic feasibility of its production.
When choosing raw materials, you should first check their availability - both physical and financial. That is, find out if it is possible to purchase and deliver required amount raw materials at reasonable prices. Also, it is necessary to accurately determine the volume of production and, accordingly, determine the volume of raw materials that will be required. And after that, it doesn’t hurt to make sure that it is really possible to obtain raw materials in a given volume.
Also, it is necessary to take into account the resource intensity of the raw material, the number of stages required for its processing, as well as the number of by-products and the possibility of their use as secondary raw materials.
In addition, it is necessary to estimate the volumes of wastewater and emissions in advance. Too many of them will entail the development and construction of special cleaning systems, which, of course, is necessary, but is not economically profitable.
Raw materials for the chemical industry are required in huge quantities. The cost of raw materials greatly influences the cost of the final product, so the main efforts of scientists and engineers in this area should be concentrated on methods of saving raw materials, including replacing expensive raw materials with cheap ones and striving for maximum use of the entire volume of raw materials. After all, any success in this direction will not only reduce the cost of products, but will also contribute to the intensification of the development of the chemical industry as a whole.
Raw materials are called natural materials, used in the production of industrial products. Raw materials are main element production, on which its efficiency, choice of technology, equipment and also product quality depend. An intermediate product is a raw material that has been processed at one or more stages of production, but is not a commercial target product. The intermediate product can be the raw material for the next stage of production. A by-product is a substance that is formed during the processing of raw materials in parallel with the target product, but is not the purpose of this production. Industrial waste refers to the remains of raw materials, materials and intermediate products generated in production, which cannot be used as commercial products, having partially or completely lost their qualities.
Classification of raw materials Chemical raw materials are classified according to their origin, chemical state, resources and state of aggregation. By aggregate By chemical By type of reserve state Solid Liquid Gaseous By origin Mineral, including: Inorganic Renewable – ore, – non-ore, – combustible Vegetable Organic Non-renewable and animal Water Air
Classification of raw materials Chemical raw materials are divided into primary and secondary: primary raw materials are extracted from natural sources; secondary raw materials are intermediate and by-products of industrial production and consumption. It should be noted that capital investments in the processing of secondary raw materials are on average four times less than for the processing of primary raw materials. In industrial developed countries reuse metals and alloys is: steel – 70; copper – 55; aluminum and tin – 45 each; zinc – 21% wt. Another principle of classification of raw materials involves their division into natural and artificial (obtained through industrial processing of natural raw materials).
General requirements to raw materials Raw materials must ensure: Ø low-stage production process; Ø the state of aggregation of the system, ensuring minimal energy consumption to create optimal conditions for the technological process; Ø minimal losses of supplied energy in environment; Ø minimal energy losses from process products; Ø Possibly milder process conditions (contact time, temperature, pressure) and minimal energy consumption to change the aggregate state of the reagents and implement the technological process; Ø maximum yield of the target product.
Rational use raw materials Share of raw materials in cost commercial products is the main one and reaches 70%. The chemical industry uses compounds of more than 80 elements as raw materials. These elements are mainly found in earth's crust and are distributed in it extremely unevenly both in nature, and in concentration, and in geographical location. The fraction per element contained in the earth's crust is called clarke. Element O Si Al Fe Ca Na Mg K H t Clark, 49, 13 26, 0 7, 45 4, 20 3, 25 2, 40 2, 35 1, 00% Nine elements account for 98% of the mass of the earth's crust. The share of all other elements is only 1.87%. Of these, the clarke of carbon, which forms the basis of life, is 0.35%.
Rational use of raw materials All resources of chemical raw materials are divided into reserves, i.e. identified and studied, and potential resources. In turn, according to the degree of study and suitability for exploitation, raw material reserves are divided into three categories: Ø category A – these are reserves that have been explored in detail and prepared for development; Ø category B – these are reserves established as a result of geological exploration; Ø Category C – these are reserves determined based on the results of geophysical exploration and study of natural outcrops.
Rational use of raw materials The possibility of using raw materials for industrial production is determined by its value, availability and concentration of the useful component. The value of raw materials depends on the level of technology development and the challenges facing production, and may change over time. For example, uranium, previously a waste product during the production of radium, is now an important strategic raw material. The availability of raw materials for extraction is determined by the geography of the deposit, its depth, and the development industrial methods extraction, the availability of human resources for its operation. A significant factor determining the possibility of using raw material reserves is the concentration of the target element.
Rational use of raw materials Russia accounts for the world's reserves (in mass %): gas - 40, fossil coals - 23, oil - 6 -8, wood - 30, peat and potassium salts - more than 50, various mineral raw materials- about 20, including more than 27 iron and tin, 36 nickel, 11 copper, 20 cobalt, 12 lead, 16 zinc, 40 platinum group metals. In terms of gold reserves, Russia ranks third in the world. It should be added that 20% of the world's fresh water reserves are concentrated in Russia.
Preparation of mineral raw materials In the chemical industry, the efficiency of the technological process largely depends on the type of raw material, quality and its cost. Before use, mineral raw materials are subjected to special training, which includes two stages: Ø purification from impurities that negatively affect the further course of the chemical transformation, this stage is the main operation in the preparation of raw materials; Ø increasing the concentration of a valuable component, so concentrated raw materials are economically and technologically more efficient.
Preparation of mineral raw materials The process of purification and separation of solid raw materials is called enrichment. For liquid and gaseous raw materials, the term concentration is used. Enrichment of mineral raw materials is based on the use of differences in physical, physico-chemical and chemical properties components. Enrichment methods are varied and fundamentally different for solid, liquid and gaseous raw materials. As a result of enrichment, the following components are obtained: Ø concentrate is a fraction enriched with a useful component; Ø tailings are waste rock. Enrichment methods are divided into mechanical, physical and physicochemical.
Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Scattering (or rumble) is separation hard rock, based on the different strengths of the components. The crushed raw materials are passed sequentially through screens, which are metal sieves with holes of various sizes. During screening, grains of various sizes are formed, resulting in separation into fractions enriched with a specific mineral.
Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Gravity enrichment is based on different falling speeds of particles of crushed material having different densities, shapes and sizes. This separation is carried out either in a liquid stream (wet gravity enrichment), or in a gas stream or under the influence of centrifugal forces.
Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Schematic diagram wet gravity enrichment
Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Wet gravity enrichment devices include a hydrocyclone, the operating principle of which is based on the action of centrifugal force.
Preparation of mineral raw materials Physical methods enrichment – electrostatic and electromagnetic separation, thermal method. Electromagnetic separation and electrostatic separation are based on differences in the magnetic permeability or electrical conductivity of the raw material components. Electromagnetic enrichment is used to separate magnetically susceptible particles from non-magnetic ones, and electrostatic enrichment is used to separate electrically conductive substances from dielectrics. The separation is carried out in electromagnetic or electrostatic separators, which have a similar operating principle.
Preparation of mineral raw materials Physical methods of enrichment - electrostatic and electromagnetic separation, thermal method. Electromagnetic separator diagram:
Preparation of mineral raw materials Physical methods of enrichment - electrostatic and electromagnetic separation, thermal method. Thermal enrichment of solid raw materials is based on the difference in melting temperatures of the raw material components. For example, by heating sulfur-containing rock, fusible sulfur is separated from waste rock, consisting of more refractory limestone, gypsum and other minerals.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation is one of the largest-scale technological processes for the enrichment and separation of solid mineral raw materials. There are foam, film and oil flotation. The basis of all types of flotation is the difference in wettability liquid phase gangue particles and valuable extractable material.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Let's look at the basics of flotation using the example of froth flotation. The pre-crushed material is intensively mixed in water, a pulp is formed, through which air is bubbled. Typically, particles of valuable material are poorly wetted by water, are captured by air bubbles and are carried to the surface of the water in the form of foam. This foam is then mechanically removed and sent to further processing, and the well-wetted waste rock passes into water.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Mineralized foam (foam product) is called flotation concentrate. As a rule, it is a valuable component of the enriched raw material. Particles that are well wetted and remain in the pulp form a chamber product (or tailings). As a rule, this is waste rock. The wettability of minerals is characterized by the contact angle, which is formed along the linear interface T – L – G:
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Most minerals natural ores differ little in wettability from each other. To separate them, conditions of unequal water wettability of the individual components are created. To increase the efficiency of the flotation process (to increase selectivity, speed up and create stable foam), so-called flotation reagents are added to the flotator. The consumption of flotation reagents is low and can be hundreds of grams per ton of raw material. This allows the use of even relatively complex and expensive surfactants for fine control of the surface properties of the separated materials.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Collectors (or collectors) – promote the formation of hydrophobic films on the surface of hydrophilic particles. Hydrophobized particles adhere to air bubbles and rise to the surface of the pulp into foam and are removed along with it in the form of a flotation concentrate. Collectors are surfactants containing a polar and nonpolar group. For example, fatty acid and their soaps (oleic acid, naphthenic acid), as well as xanthates, most often potassium xanthate.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Foaming agents – provide bubble stability sufficient to deliver particles to the surface of the flotator. Mineralized foam should be moderately stable, dense and flexible. The foam layer should contain as much less water in order to facilitate further processing. Surfactants are used as foaming agents, forming adsorption films on the surface of air bubbles. The most effective foaming agents include pine oil, coal tar fractions, and aliphatic alcohols.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Suppressors (or depressors) - used to increase the wettability of mineral impurities, they facilitate the transition of these impurities into tailings (or chamber product). Electrolytes (lime, cyanides, sulfites, zinc sulfate, sodium silicate) act as suppressants. Ø Activators – help enhance the adsorption of collectors. They are often used to separate tails and eliminate the effects of suppressors. Copper sulfate, sulfuric acid, and sodium sulfide act as activators. Environmental regulators are lime, soda, sulfuric acid and other substances.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. There are collective and selective flotation. Collective flotation is a process in which a concentrate is obtained containing all useful components, and waste rock. The collective concentrate is then separated into its individual constituent components. This separation is accomplished by selective (or selective) flotation. In this case, in addition to collectors and foaming agents, depressants are introduced into the process. They are able to enhance the hydrophilicity of certain minerals, preventing them from floating. Subsequently, activators are added, which remove the effect of depressants and promote the floating of minerals.
Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Extraction is the process of selectively removing one or more components from aquatic environment into liquid organic. It is assumed that the organic phase is practically insoluble in the aqueous phase. After phase separation, the extracted component is again transferred to the aqueous phase. This process is called re-extraction. In this case, the extractant is regenerated. Good extractants are carboxylic or naphthenic acids, amines, and quaternary ammonium bases, which are readily soluble in kerosene or hexane. Requirements for extractants: Ø ease of regeneration; Ø non-toxic; Ø low cost.
Preparation of gaseous raw materials Gaseous raw materials can be natural or industrial origin. Natural raw materials are represented by hydrocarbon gases (natural gas) and air. Gases are used as gaseous raw materials of industrial origin coke production(coke oven gas), oil refining gases (associated gas), metallurgical production gases, processing gases solid fuel(producer gas). Methods for the enrichment of gaseous multicomponent systems (or purification and separation of gas mixtures) are based on differences in the properties of the components of the mixture (for example, differences in boiling points, solubility in a solvent, sorption capacity).
Preparation of gaseous raw materials Separation of gases: Ø air is separated into nitrogen and oxygen; nitrogen is used in the production of ammonia, and oxygen is used as an oxidizing agent in the chemical industry and metallurgy. In addition, argon is released from the air; Ø ammonia is isolated from coke oven gas in the form of ammonium sulfate; hydrogen, which is then used to obtain a nitrogen-hydrogen mixture; and hydrogen sulfide, which is used to produce sulfuric acid. Gas purification: Ø natural gas used in the production of ammonia is purified from sulfur-containing compounds; Ø the converted ammonia production gas is purified from carbon dioxide; Ø before the ammonia synthesis column, the nitrogen-hydrogen mixture is purified from traces of oxygen-containing compounds.
Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø the condensation method is that when the gas mixture is cooled, higher boiling components condense first and are separated in separators. In the production of synthetic ammonia, ammonia is separated from the unreacted nitrogen-hydrogen mixture by condensation. Hydrogen is released from coke oven gas by fractional cooling.
Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø sorption methods are based on the different sorption abilities of the components by some absorber. In sorption processes there are: adsorption and absorption. Adsorption is the process of absorption of one or more components of a gas mixture by the solid surface of an adsorbent. The absorption process is carried out in devices called adsorbers. There are types of adsorbers: with a fixed layer of adsorbent, with a moving layer, and also with a fluidized bed. The adsorber operates in the “adsorption ↔ desorption” mode. The following are used as adsorbents: Activated carbon, zeolites, porous glasses.
Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø sorption methods are based on the different sorption abilities of the components by some absorber. In sorption processes there are: adsorption and absorption. Absorption is the selective absorption of one or more components of a gas mixture by a liquid absorbent (absorbent). Organic and inorganic solvents are usually used as absorbents. Purification and separation of the gas mixture takes place in two apparatuses. In one (absorber) absorption of any component by a cooled absorbent occurs, in the other (regenerator) desorption occurs, while the absorbed substance is released from the solution and the absorbent is regenerated.
Preparation of gaseous raw materials Basic methods for separating gas mixtures: Ø The membrane method for purifying gas mixtures is based on separation using microporous partitions (or membranes) that are permeable to molecules of one type and impermeable to molecules of another type. The membrane separation method is the most advanced, since it eliminates high pressures And low temperatures. In membrane devices, air is separated into nitrogen and oxygen, methane and hydrogen, methane and helium. Gases are also purified from dust and moisture.
Raw materials are materials intended for further processing in production. In fact, this is where the production of any product begins. It is difficult to overestimate the role of the source material, since the quality of the product depends on this. Today there is great amount various groups, subgroups and types of raw materials. Let's try to understand this diversity.
What are raw materials for production
Collected or mined materials are usually processed to make them marketable. In the future, they either go on sale or continue to participate in subsequent ones until they reach the stage of the final product.
Types of raw materials
Classification of raw materials is a very conditional concept. It is customary to distinguish two main groups: industrial and agricultural. Industrial includes minerals and energy resources. Agricultural raw materials are grains, dairy products, meat, medicinal plants. All types of raw materials can be divided into two more groups: they can be primary (directly mined or collected) and secondary (in the form of a by-product or The secondary group of materials is widely used in industry, which can significantly reduce costs. By origin, all types of raw materials can be divided into 4 subgroups:
- Plant origin (cereals, herbs).
- Animal origin (dairy products, animal excrement).
- Mineral coal).
- Biosphere (water and air).
Use of raw materials in production
Today there are a huge number of industries. The list of traditional industries is updated daily with new names, which means new raw materials are being developed and used. This is due to both growing global demand and developing technologies. The most pressing area today is the development of energy resources. If a hundred years ago people were able to obtain energy from oil and coal, today other sources are being actively developed, for example. There is an alternative technology for generating electricity based on natural fermentation processes, when cow dung acts as an energy carrier. But production such as the production of cotton fabric has remained virtually unchanged for many centuries. The process itself has been improved and mechanized, but the raw materials are cotton bolls - just as it was 3-4 centuries ago. A food industry is constantly undergoing change. The manufacturer's desire to reduce costs results in a search for new types of the original product. Natural raw materials are best option. However, unfortunately, in order to save money, it is often replaced with artificial one. Thus, today we can observe a situation in which some manufacturing industries continue to use some raw materials for centuries, while others develop technologies and develop new types of raw materials.