Полисульфид натрия

Description

Sodium polysulfide Na₂Sₓ is a general designation for a number of salts of composition from sodium disulfide to sodium pentasulfide, differing in the number of sulfur atoms in the chain. The product is obtained by dissolving sulfur in a solution of sodium sulfide; in commercial form it is supplied as a solution. The polysulfide ion is a strong reducing agent and at the same time a sulfur donor, which determines a set of applications: deashing and liming of hides in tanning, a depressant reagent in the flotation of sulfide ores, the synthesis of sulfur dyes and polysulfide rubbers (thiokols), gas desulfurization, waste treatment with the precipitation of heavy metals in the form of sulfides.

Basic Attributes

• CAS No.: 1344-08-7
• Molecular weight: 57.066
• Exact weight: 56.977
• EU number: 215-686-9
• DSSTox ID: DTXSID9051296
• PSA Features: 1

Physico-chemical characteristics

• Appearance: liquid
• Melting point: 400 °C

Chemical behavior

Solutions of polysulfides have a highly alkaline reaction and are colored from yellow to red-brown depending on the length of the sulfur chain. Acidification decomposes polysulfide with the release of hydrogen sulfide and elemental sulfur, so contact with acids is unacceptable. Air oxygen oxidizes polysulfide to thiosulfate and sulfate, which reduces the activity of the product when stored in loose containers. GHS classification includes H251 - Self-heating and may catch fire.

Scope of application

• leather production: liming and deliming of hides
• flotation of sulfide ores - depressant and mineral surface modifier
• synthesis of sulfur dyes
• production of polysulfide rubbers (thiokols) and sealants based on them
• purification of gases from sulfur-containing compounds
• wastewater treatment: precipitation of heavy metals in the form of sulfides

Safety Information

• Packing level: I
• Hazard category: 4.2
• Transport code: 3200
• Hazard class code: 25-31-34-50
• Safety instructions: 26, 36/37/39, 45, 61
• Tags: T, N
• Hazard Statements: H301 - Toxic if swallowed
• Precautions: P260, P264, P270, P273, P280, P301+P310, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P391, P405, P501
• GHS classification: signal word "Danger". H301 - toxic if swallowed, acute oral toxicity, prescriptions P260, P264, P270, P273, P280, P301+P310, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P391, P405, P501. H251 (33.98%) - self-heating, may ignite, hazardous self-heating substances and mixtures, regulations P234, P235+P410, P260, P264, P270, P273, P280, P301+P310, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P390, P391, P404, P405, P407, P413, P420, P501. H314 - causes severe skin burns and eye damage, prescriptions P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501. Aggregated information of 256 companies for 5 notifications to the ECHA C and L register; each notification can be associated with several companies

Storage and handling

The container is sealed, the room is cool and ventilated. Code 31 in the classification means the release of toxic gas upon contact with acids - separate storage with acids is mandatory, and hydrogen sulfide formed upon accidental contact is acutely toxic. Direction H251 requires limiting the batch size and avoiding self-heating (P235+P410, P407, P413, P420). Corrosivity (H314) and T and N labels define PPE: durable gloves, sealed goggles or face shield, protective clothing. Code 50 and regulations P273 and P391 prohibit the discharge of product and effluent into waterways and sewers.