Sale of sodium sulfide

We offer to buy sodium sulfide - this is a full-fledged integrated service with the possibility of proper packaging, delivery and an agreement on constant supplies. More favorable prices, discounts and mutually beneficial cooperation can be discussed with regular customers.

Production

The production of sodium sulfide involves sulfide roasting of barium sulfate, conversion to sodium sulfide, filtration of the resulting suspension, and isolation of the desired substance through several technological operations. It can be obtained by fusing sodium sulfate with coal at a temperature of one thousand two hundred degrees.

Appearance

In appearance, sodium sulfide is a monolithic mass, flakes or granules that can vary in color from light brown to dark brown. Sodium sulfide is highly soluble in water; its contact with acids causes the release of hydrogen sulfide, a flammable explosive gas.

Application

Sodium sulfide is used in technical form for metallurgical, light, chemical and other industrial production operations. In particular, sulfur dyes and cellulose are produced using sodium sulfide. It is used as a component for the flotation of zinc and zinc-lead-iron ores. Depending on the brand and type (granules or flakes), sodium sulfide can be used in various processes, in particular, grade A is used in enterprises for the production of leather and textile products, and grade B is an indispensable component for some non-ferrous metal production lines.

Transportation

When transporting sodium sulfide, it is necessary to comply with all safety measures for the transportation of the second class of chemicals. There is a restriction only for air transport; sodium sulfide is not carried by plane; in all other cases it is necessary to use covered vehicles or containers.

Storage

Storage of sodium sulfide requires preliminary packaging in special soft containers with storage in a closed warehouse or on container sites, storage conditions - manufacturer's packaging or tightly closed receiving containers.

Safety precautions

According to safety precautions, sodium sulfide belongs to the second class, it is a flammable and explosive substance, and is dangerous to humans.

Effect on the body

Sodium sulfide, when inhaled, causes consequences in the form of cough, chest tightness, runny nose, lacrimation and is dangerous for other mucous membranes, causing damage to the eyelids, conjunctiva and iris of the eyes. Acute exposure of unprotected skin to high concentrations of sodium sulfide can cause a chemical burn.

In industry, sodium sulfides are produced by the reduction of Na 2 SO 4 with coal at 800-1000 ° C in shaft rotary kilns.

Chemical formula: Na 2 S.nH 2 O (n=1.9 - 2.4)

Technical sodium sulfide (according to the classification of theoretical chemistry - sodium sulfide) is a compound actively used in light, metallurgical, chemical and some other industries.
In particular, the product is used as a reducing agent in the production of sulfur dyes, cellulose, for removing hair from hides during tanning, for kraft pulping, and in the smelting of certain non-ferrous metals. Sodium sulfide is also indispensable in analytical chemistry, for use as a reagent in many processes.
Sodium sulfide is an intermediate in some methods for producing soda and sodium hydroxide from sodium sulfate.

Technical sodium sulphide is produced in bulk form (granulated, flaked) and in the form of a monolith of three grades: grade A is used in the production of dyes, in the production of light leather, and is exported, grade B - in the leather and textile industry, grade B - in non-ferrous metallurgy .

Technical sodium sulphide is fire- and explosion-proof; in terms of the degree of impact on the body, it belongs to substances of the 2nd hazard class. MPC - 0.2 mg/m³.

Packaging, transportation and storage.
Technical sodium sulphide is packaged in steel drums for chemical products, specialized containers of type SK-1-5 (7), as well as in soft specialized disposable containers, paper bags lined with a rubber-bitumen mixture, four- and five-layer paper bags in an internal polyethylene bag - liner or plastic bag. The net weight of the bags is no more than 50 kg.
Technical sodium sulphide is transported by all types of transport (except air) in covered vehicles. By rail, the product is transported by wagonload and small shipments (except bags). The product, packaged in soft specialized containers, is transported on open rolling stock. Transportation of a product packaged in soft specialized containers must be carried out without overloads along the route with loading and unloading at the access roads of the consignor (consignee).
Technical sodium sulphide is stored in closed warehouses in the manufacturer's packaging or tightly closed receiving containers. Soft containers are stored on container yards.
The guaranteed shelf life of the product is 1 year from the date of manufacture.

Technical sulfur) is a compound that is quite widely used in industry. So, this substance is used in metallurgy, as well as chemical, light and other industries. Sodium sulfide, in particular, is used in the production of cellulose, dyes, and in the processing of natural leather. The substance is also used in melting a number of non-ferrous metals. Sodium sulfide is indispensable in the field of analytical chemistry. It is used as a reagent in various processes.

Sodium sulfide. Formula (Na2S)

A homogeneous mass characterized by high photosensitivity, or hygroscopic crystals, is considered normal. The substance is produced in the form of a monolith of 3 grades and in bulk form (in the form of flakes or granules). A product that is light brown, pale yellow or grayish in color is allowed to be used. A more intense or any other color indicates significant oxidation of the substance. Such sodium sulfide loses its useful characteristics and is unsuitable for practical use. The technical product contains from sixty-three to sixty-seven percent of the main substance, provided that the insoluble sediment is no more than half a percent.

In accordance with the classification according to the level of danger to humans, sodium sulfide is assigned the second class. The substance is flammable and explosive. In this regard, it is preferable to store the material in enclosed spaces that are equipped with all the means necessary to ensure fire safety. It is not recommended to remove the packaging from the product until the substance is used directly. If the container is kept sealed, sodium sulfide can be stored for up to two years. The period of effective use is only a year.

Transportation of the product should be carried out using any type of transport in closed wagons or containers. Great care must be taken when loading and unloading the substance, especially if direct contact with a product packaged in a flexible container is expected. During transportation, it is necessary to avoid temporary storage in open areas or warehouses insufficiently equipped for this.

Technical sodium sulfide produced in China is packaged in special bags of twenty-five kilograms. The container provides protection from premature oxidation and exposure to light. In addition, steel drums are used as containers exclusively for chemical products, containers (SK-1-5(7)) or soft containers for single use. The substance can be packaged in paper bags (four- or five-layer) with an inner liner - a plastic bag. Bags can have a net weight of no more than fifty kilograms.

The substance packed in specialized containers is transported in open containers.

The density of the product is 1.856 grams per cubic centimeter. reaches 1180 degrees. The product is highly hygroscopic. 13.6% of the substance dissolves in water at twenty degrees, and 45% of the substance is dissolved at 97.5 degrees. The product is capable of forming crystalline hydrates. Aqueous solutions of technical sodium sulfide are characterized by an alkaline reaction.

Hydrolysis of sodium sulfide is carried out in the same way as salts, which are formed by a weak acid and a strong base. Phenolphthalein in a test tube with a solution turns pink. This indicates that an alkaline environment has formed in the test tube. Thus, sodium sulfide, like other salts that are formed by a weak acid and a strong base, is hydrolyzed to form an alkali.

Technical sodium sulfide (according to the classification of theoretical chemistry - sodium sulfide) is a compound that is actively used in light, metallurgical, chemical and some other industries. In particular, the product is used in the production of dyes, cellulose, for the processing of natural leather, and in the melting of certain non-ferrous metals. Sodium sulfide is also indispensable in analytical chemistry, for use as a reagent in many processes.

TECHNICAL CHARACTERISTICS AND MAIN PROPERTIES

Physicochemical characteristics

The normal state of aggregation that technical sodium sulfide has is hygroscopic crystals or a homogeneous mass, which is highly photosensitivity. For a ready-to-use drug, a grayish, pale yellow, dark or light brown color of the substance is allowed. A different or more intense color indicates significant oxidation. Such sodium sulphide loses its beneficial properties and is not suitable for practical use. Technical sulfide of different grades contains from 63 to 67% of the main substance with a mass fraction of insoluble sediment not exceeding 0.5%.

PACKAGING AND STORAGE

Security and storage

According to the classification of danger to the human body, sodium sulfide is assigned class 2. It is flammable and explosive, which requires special conditions for transportation and storage of the substance. The preferred option for storing material is to use closed premises for these purposes, equipped with the necessary fire protection equipment. It is not recommended to remove the manufacturer's packaging before immediate use. If the container remains sealed, the substance can be stored for up to 24 months. Moreover, the warranty period for effective use is only one year.

Transportation

Sodium sulphide can be transported by any means of transport in closed containers or wagons. At the same time, special attention is required to the safety of loading and unloading operations, especially when it comes to direct contact with a substance packaged in a soft container. During the journey, overloading or temporary storage of cargo in insufficiently equipped warehouses or open areas should be avoided.

Package

Technical sodium sulfide made in China is packaged in 25 kg bags in special bags that protect the substance from exposure to light and premature oxidation.

THE CONTACT PERSON

Manager Memyashova Svetlana

Introduction

Industrial methods for producing sodium sulfide involve the use of both natural raw materials and associated or by-products of chemical production.

Sodium sulfide is produced in the following ways:

)reduction of sodium sulfate with solid carbonaceous materials;

) reduction of sodium sulfate with gaseous reducing agents;

) absorption of sodium hydroxide hydrogen sulfide;

)electrolytic (amalgam) method;

) exchange decomposition of barium sulfide by sodium sulfate, carbonate and sodium hydroxide.

But the main way to obtain sodium sulfide is the thermal reduction of sodium sulfide with solid carbonaceous materials.

Throughout the entire existence of sodium sulfide production, only its equipment has changed. At first these were hearth furnaces, then rotary drum furnaces and, finally, continuous shaft furnaces. The practice of operating shaft furnaces has revealed a number of its significant advantages: high intensity, high heat utilization coefficient, the ability to operate the furnace on wet raw materials, and most importantly, continuity of the process.

The yield of sodium sulfide achieved in practice relative to the consumed sodium sulfate is 60-75% of the theoretical one.

1. Physical properties of sodium sulfide Na 2 S

sodium sulfide absorption electrolytic

Na 2 S - sodium sulfide, oxygen-free salt, white, very hygroscopic, density 1.856 g/cm 3, t pl = 1180 ° C, t boil = 1300 o C. Molecular weight of sodium sulfide M = 78.01. Solubility in water (%): 13.6 (20 °C), 45.0 (97.5 °C). At temperatures below 48 o C, crystalline hydrate Na 2 S 9H 2 O crystallizes from an aqueous solution, above 48 o C - Na 2 S 6H 2 O.

In water, sodium sulfide is hydrolyzed: Na 2 S + H 2 O = NaOH + NaHS.

Sodium sulfide, when interacting with acids, releases hydrogen sulfide, is easily oxidized by atmospheric oxygen to thiosulfate, and then to sodium sulfite and sulfate, and also forms polythionic acids. It is dissolved in lower alcohols (methanol, standard), which is used in practice to obtain pure sodium sulfide.

Na 2 S is a strong reducing agent: dilute nitric acid oxidizes sodium sulfide to sulfur S, concentrated HNO 3 to Na 2 SO 4 (sodium sulfate). Sodium sulfide reacts with hydrohalic acids and dilute H 2 SO 4 to release H 2 S and sodium hydroxide.

Preparation of sodium sulfide by reduction of sodium sulfate with coke

Theoretical basis

When a mixture of sodium sulfate and coke is heated to 950-1200 °C, the following overall reactions occur:

Na 2 S0 4 + 4C = Na 2 S + 4CO (b)

Na 2 S0 4 + 4CO = Na 2 S + 4CO 2 (c)

A significant amount of sodium sulfide is formed by reaction (a). Simultaneously with the main chemical process, side processes occur, as a result of which the melt contains impurities of carbonate Na 2 CO 3, thiosulfate Na 2 SO 3 and sodium silicate Na 2 SiO 3 and other salts. Side reactions lead to the consumption of raw materials and contamination of products with ballast salts.

The degree of reduction of sodium sulfate depends on the contact surface of the phases, the ratio of sodium sulfate and coal and the content of impurities in the charge, temperature, etc.

To increase the contact surface of the reacting phases, the mixture is composed of briquettes of sodium sulfate and pieces of coke. However, under production conditions, intensive reduction begins only after the appearance of the liquid phase of sodium sulfate, wetting the surface of the coke particles.

Coke is introduced into the charge in excess, since some of it burns out in the furnace and does not participate in the reduction process. Excess coke increases the viscosity of the melt, reduces its thermal conductivity, and, ultimately, reduces the productivity of the furnace. The optimal ratio of Na 2 SO 4 and coke is established experimentally in the factory.

The process of producing sodium sulfide melt can be divided into three main periods: melting, “boiling” and maturation.

In the first period, the charge is heated and the sodium sulfate melts. Pure sodium sulfate melts at 890°C, but if the mixture contains impurities of sodium sulfide, sulfates and sulfides of alkali and alkaline earth metals, the melting point of sodium sulfate decreases. During the melting period of sodium sulfate, the rate of its recovery gradually increases. The formation of Na 2 S is accompanied by the release of gaseous carbon monoxide (IV).

The second period of recovery is characterized by rapid gas release; the melt seems to be “boiling.” The optimal process temperature is 950°C. This period corresponds to the highest rate of sodium sulfate reduction. The resulting sulfide dissolves in the melt, forming a liquid solution with sodium sulfate. When the concentration of Na 2 S in a solution reaches 70%, the solution becomes saturated. The Na 2 S formed further will no longer dissolve, but will be in a solid state. The solution begins to thicken.

The third period begins - the period of maturation. The rate of sodium sulfide formation decreases. The amount of liquid phase (sodium sulfate) continuously decreases, the melt becomes viscous and mushy. To reduce the viscosity of the melt and facilitate its unloading from the furnace, the temperature in the furnace is increased to 1200-1300 °C.

The finished melt usually contains 68-75% Na 2 S, 5-13% Na 2 CO 3, 1-3% Na 2 S 2 O 3, up to 2% Na 2 SiO 3, 13-15% insoluble minerals and up to 8 % carbon (unburned coke).

Technological scheme for producing sodium sulfide

The technological process for the production of sodium sulfide consists of the following main stages:

1) production of sodium sulfide melt in a furnace;

) leaching of sodium sulfide with hot water or mother liquor;

)filtration of liquors and their purification;

)reduction of liquors to produce fused sodium sulfide.

Technological schemes for the production of sodium sulfide differ mainly in their hardware design. The recovery of sodium sulfate is carried out in mechanical rotary kilns of batch action, as well as in continuous shaft and cyclone kilns.

In Fig. Figure 1 shows a diagram for the production of Na 2 S by the reduction of sodium sulfate with coke in shaft-type furnaces.

Fig.1. Scheme for producing Na 2 S by reducing sodium sulfate with coke in shaft-type furnaces. 1 - conveyors; 2 - cyclone; 3 - fans; 4, 6 - vacuum filters; 5, 15, 16, 18, 23, 25, 28 - collections; 7 - Dorra settling tank; 8 - evaporator; 9 - barometric capacitors; 10, 29 - vacuum pumps; eleven - vacuum collectors; 12 - charge bunker; 13 - shaft furnace; 14, 17, 24, 26 - centrifugal pumps; 19 - evaporation boilers; 20 - bugle; 21 - leachate; 22, 27 - exhaust pipes.

Briquetted sodium sulfate and coke are mixed on conveyor belt 1 in a ratio of 2:1. The resulting charge enters shaft furnace 13 through the loading hopper and feeder.

Shaft furnace is a two-cone tower 6.8 m high. Its lower part ends with a forge 20 in the form of a cylindrical bowl. The forge is mounted on a trolley and rolls to the side when repairing the furnace. The forge is equipped with two copper tapholes for continuous release of melt. The tapholes and the lower part of the furnace - the caisson - i.e. the zones of the highest temperatures, have water jackets on the outside to remove heat. In the zone of highest temperatures, the furnace is lined with chromium-magnesite bricks or ceramics, the rest of the furnace is lined with fireclay bricks. Above the furnace there are six tuyere holes through which the air necessary for burning coke is sucked into the furnace.

In the upper part of the furnace, the charge is heated by the heat of the exhaust gases. Once in the reaction zone, sodium sulfate melts and is reduced. Exhaust gases are cleaned of dust in cyclone 2 and is released into the atmosphere by a fan. The cyclone has a water jacket for cooling the exhaust gases from 400 o to 150-200°C.

The sodium sulfide melt from the shaft furnace tapholes continuously enters the lixiviator 21 , which is a tank with a conical bottom made of stainless steel. It has a two-blade mixer for mixing the pulp and is equipped with a 22 exhaust pipe to remove water vapor released during melt quenching. Leaching of sodium sulfide is carried out with weak alkalis (6-12% Na 2 S) formed after washing the sludge. The lye is supplied to the apparatus by pump 14 from collection 15 . Dissolution of Na 2 S occurs at 115°C to obtain a solution with a concentration of 30% Na 2 S. This solution is collected in collection 25 , and then it is pumped by pump 26 into the pressure tank 5, from where it flows by gravity to the disk vacuum filter 6 .

After filtration, strong liquors are collected in collection 16 and pumped into the Dorra settling tank 7. The remaining sludge is washed with hot water in a repulpator (not shown in the figure) for deeper extraction of Na 2 S. The resulting washing solutions are separated from the sludge using a vacuum filter 4 and returned to the leachate, and the sludge is sent to sludge ponds.

After clarification in the Dorra settling tank 7, a 30% solution of Na 2 S is supplied to the evaporator 8 by a vacuum pump With remote heating chamber. Here, as a result of evaporation, its concentration increases to 50% Na 2 S. The final evaporation of the liquor is carried out in a cascade of evaporation boilers 19 , where the solution flows by gravity from collection 18 . The boilers are heated by flue gases obtained by burning natural gas.

The melt, evaporated to contain at least 67% Na 2 S in the product, is transferred by vacuum pump 29 in collection of swimming pool 28 , and from here it is poured by gravity into drums, where it hardens within 24 hours into a solid mass. To obtain a bulk product, the melt is fed either onto the surface of rotating hollow steel drums, cooled from the inside with water, or granulated in a stream of cooled air in a KS apparatus.

In the production of sodium sulfide, the supply of charge to the shaft furnaces is automatically controlled according to the temperature of the exhaust gases or according to the level of the charge in the furnace. Automatically maintain liquor levels in vacuum filters. All collections are equipped with a light alarm for the solution level and automatic shutdown of the solution supply is provided when the maximum level is reached.

Expense ratios per 1 ton of product containing 67% Na 2 S:

Sodium sulfate (95% Na 2 S), t…………1.65

Cox, t…. ................................ 0.80

Electricity, kWh............ 405

4. Preparation of sodium sulfide by reduction of sodium sulfate with gases

Hydrogen, natural, generator and other gases can be used to restore sodium sulfate. The use of gaseous reducing agents makes it possible to obtain 96% solid sodium sulfide directly without the cumbersome operations of melt leaching, filtration and evaporation of the solution.

Currently, hydrogen is used abroad as a reducing gas on an industrial scale. The reduction of sodium sulfate with hydrogen proceeds according to the reaction: Na 2 SO 4 + 4H 2 = Na 2 S + 4H 2 O.

The process is carried out in horizontal rotary and shaft kilns in the presence of an iron catalyst, which is added to sodium sulfate in a small amount in the form of an aqueous solution of FeSO 4 or in the form of cinder dust from the electric precipitators of pyrite furnaces. The catalyst accelerates the reaction of sodium sulfate reduction and allows it to be carried out at 600-650°C without melting the product. The main disadvantage of this method is the high consumption of hydrogen. More promising is the use of natural gas as a reducing agent.

Conclusion

Sodium sulfide is widely used in non-ferrous metallurgy for the enrichment of copper, lead-zinc, molybdenum and other ores, in the leather industry for removing hair from skins, in the textile industry for dyeing fabrics, in the chemical industry for the production of sulfur dyes and as a reducing agent in a number of processes.

Harmful substances in the production of sodium sulfide are its melt, liquor and the finished product. When they come into contact with the skin, they cause severe, long-lasting burns, and when they enter the body they cause poisoning.

List of used literature

1)Melnikov E.Ya., Saltanova V.P., Naumova A.M., Blinova Zh.S. Technology of inorganic substances and mineral fertilizers: Textbook for technical schools. - M.: Chemistry, 1983. - 432 p.

) Lidin R.A., Andreeva L.L., Molochko V.A. Handbook of Inorganic Chemistry. Constants of inorganic substances. M.: Chemistry, 1987. - 320 p.

) http://ru.wikipedia.org/

) http://www.xumuk.ru/encyklopedia/