Sodium sulfide ( technical sodium sulfide) is a compound that is widely used in industry. So, this substance is used in metallurgy, as well as in the chemical, light and other industries. Sodium sulfide, in particular, is used in the production of cellulose, dyes, in the processing of natural leather. The substance is also used in the melting of 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 normal aggregate state of a substance is considered to be a homogeneous mass, characterized by high photosensitivity, or hygroscopic crystals. The substance is available in the form of a monolith of 3 grades and in bulk form (in the form of flakes or granules). It is allowed to use a product that has a light brown, pale yellow or grayish color. More intense or any other color indicates a significant oxidation of the substance. Such sodium sulfide loses useful characteristics and is unsuitable for practical use. A technical product contains from sixty three to sixty seven percent of the main substance, provided that the mass fraction of insoluble sediment is not 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 combustible 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 directly used. While maintaining the tightness of the container, sodium sulfide can be stored for up to two years. The effective use period is only one year.
Product transportation should be carried out using any means of transport in closed wagons or containers. Much attention should be paid to loading and unloading the substance, especially if direct contact with the product is packaged in soft containers. During transportation, it is necessary to avoid temporary storage in open areas or warehouses that are not adequately equipped for this.
Technical sodium sulphide made in China is packed in special bags of twenty-five kilograms. The container provides protection against premature oxidation and exposure to light. In addition, steel drums exclusively for chemical products, containers (SK-1-5 (7)), or soft containers for single use are used as containers. 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 not more than fifty kilograms.
The substance packed in specialized containers is transported in open-type rolling stock .
The density of the product is 1.856 grams per cubic centimeter. The melting point reaches 1180 degrees. The product is highly hygroscopic. In water at twenty degrees it dissolves 13.6%, at 97.5 degrees - 45% of the substance. The product is capable of forming crystalline hydrates. For aqueous solutions of sodium sulphide technical, an alkaline reaction is characteristic.
The hydrolysis of sodium sulfide is carried out in the same way as salts, which are formed by weak acid and strong base. Phenolphthalein in a test tube with a solution becomes pink. This indicates that an alkaline medium has formed in the test tube. Thus, sodium sulfide, like other salts that are formed by weak acid and strong base, is hydrolyzed to form as a result of alkali.