Description
Application of sodium lignosulfonate:
- In the concrete manufacturing process
- Production of building materials (sodium lignosulphonate is used to improve handling and flowability of bulk materials, reducing dust and facilitating storage)
- Oil industry
- Mining
- Metallurgy
- Chemical industry
- Sodium lignosulphonate: a versatile additive used in various industries such as construction, ceramics, and rubber vulcanization for its dispersant, binder, and preservative properties
Sodium lignosulfonate in the chemical industry:
| Properties | Value standard |
|---|---|
| Liquid | |
| Appearance | Dark brown, dense liquid |
| Weight fraction of dry matter,%, min | 55-60 |
| Ash content, related to dry matter weight,%, max. | 26 |
| Hydrogen ion concentration of the lignin sulphonate solution, unit рН, min | 4.5 |
| Mass fraction of reducing substances,%, max. | 15 |
| Density , kg/m³, min | 1280 |
Sodium lignosulfonate is typically recovered from pulping liquids as a dense liquid product.
Minimum order 24 tonnes (1 Tank container)
What is sodium lignosulfonate in the pulping process?
Sodium lignosulfonate (also spelled sodium lignosulphonate) is the sodium salt of lignosulfonic acid – a polymeric compound derived from wood lignin during the pulp production process. Lignin is present in wood and is separated during the pulping process. It appears as a brown liquid with a characteristic odor and is used as a plasticizer, dispersant, binding agent, and binder in many branches of industry. Sodium lignosulfonate is widely used to improve the properties of slurries in construction and ceramics. It functions as dispersing agents and binding agents in various industries, including ceramics, refractory products, and chemical manufacturing. It is also applied in the manufacture of lead-acid batteries, where it helps in the processing of lead pastes. In ceramics, sodium lignosulfonate improves the dispersion of mineral powder, enhancing product quality. It serves as a grinding aid in cement production, improving efficiency and reducing energy consumption. Chemically, sodium lignosulfonate is a type of sulfonated lignin, related to but distinct from kraft lignin. It is also used in the processing of carbon black to improve handling and reduce dust emissions. When handling sodium lignosulfonate, it is important to avoid direct contact with skin, eyes, or inhalation. Many companies use sodium lignosulfonate in industrial processes due to its versatility. In building materials, it plays a role in forming a layer of stucco between sheets in plasterboard and other products. It is used as a tanning agent in leather processing, improving dye and tanning agent penetration. In agriculture, sodium lignosulfonate facilitates the absorption of nutrients and supports plant health. Proper storage is essential to maintain product quality and prevent spoilage or contamination. Its use leads to a reduction of water content in construction materials, resulting in energy savings. Compared to alternatives, sodium lignosulfonate offers environmental advantages in applications such as plant nutrition and dust suppression. It is derived from softwood and tropical tree sources, and belongs to the broader class of lignosulfonates. The percentage of sodium lignosulfonate used varies by application, depending on required performance. Its properties and applications are influenced by factors such as molecular weight, degree of sulfonation, and other factors like purity and amphiphilicity. Sodium lignosulfonate also contributes to plant protection by enhancing resistance to pests and environmental stresses. Lignin, from which it is derived, is also present in some algae species, providing structural support. During manufacturing, sodium lignosulfonate aids in the formation of particles or structures, such as flakes or sheets. It is used as dispersing agents in industrial processes, including ore flotation, emulsion stabilization, and chemical manufacturing.
What are the properties of sodium lignosulfonate?
It is highly hydrophilic – easily soluble in water (but insoluble in organic solvents). Its solutions may have a slightly acidic pH (around 3–5, although neutral forms also exist). It acts as an anionic surfactant: it reduces surface tension but does not foam strongly. It has dispersing properties and can chelate metals. It is chemically stable and biodegradable over time.
The properties of sodium lignosulfonate can vary depending on factors such as molecular weight, degree of sulfonation, and other factors like purity and processing conditions.
How is sodium lignosulfonate produced?
Sodium lignosulfonate is manufactured as a by-product of the pulping process in the paper industry, where lignin is separated from wood to produce pulp. During this process, lignin undergoes sulfonation—a chemical reaction in which sulfonic acid groups are introduced into the lignin structure using a strong oxidizing agent. This transformation results in a water-soluble, anionic compound that acts as an effective dispersant and binder across multiple industries.
The manufacturing process typically begins with the extraction of lignin from wood, followed by its treatment with sulfonic acid groups in a controlled industrial setting. The resulting sodium lignosulfonate is then processed into a yellow-brown powder or dense liquid, depending on the intended application. The chemical industry plays a central role in refining and standardizing the product to meet the specific requirements of various sectors.
Production methods can vary depending on the industry and the properties needed in the final product. For example, in the textile industry, sodium lignosulfonate is tailored to act as a dispersing agent for dyes and other insoluble solids, ensuring even distribution and improved colorfastness. In the petroleum industry, it is formulated to enhance the viscosity and flow of drilling fluids, aiding in the efficient extraction of oil. The construction industry relies on sodium lignosulfonate as a binder and dispersant in concrete and mineral slurries, where it helps reduce the water required for mixing, improves workability, and contributes to lower kiln temperatures—ultimately saving energy and supporting more sustainable building materials.
Beyond these applications, sodium lignosulfonate is also used in the production of ceramics, where it improves the dispersion and flow of mineral powders, and in coatings, where it acts as a dispersant to maintain the stability of pigments and other additives. In animal feeds, it serves as a binder and preservative, helping to maintain the integrity and shelf life of feed pellets. The EPA has approved sodium lignosulfonate for use in various industrial processes, including as a coating agent and dispersant in coatings, due to its non-toxic and biodegradable nature.
The energy efficiency of sodium lignosulfonate production is another key advantage. By reducing the water content required in processes such as pulping and concrete production, it enables lower kiln temperatures and significant energy savings. This not only reduces operational costs but also minimizes the environmental impact of these industries.
Overall, the production of sodium lignosulfonate is a vital process in the chemical industry, supporting a wide range of applications in the petroleum industry, textile industry, construction, ceramics, and more. Its ability to act as a dispersant, binder, and additive for insoluble solids and mineral powders makes it an essential material for improving the efficiency, sustainability, and performance of modern industrial processes.
What is sodium lignosulfonate used for as dispersing agents?
It has numerous applications. The largest use is in construction – as a concrete admixture that reduces water content and improves workability. In agriculture, it is used as a chelating agent for micronutrients in fertilizers and as a soil conditioner (binding soil particles, retaining moisture, and reducing dust). In industry, it serves as a dispersant (e.g., for pigments, pesticides), a binder (for feed pellets, briquettes), an emulsion stabilizer, and an additive to adhesive resins. It is also included in animal feed and sometimes used in pharmaceuticals as an excipient in tablets.
Is sodium lignosulfonate harmful to the environment?
No, sodium lignosulfonate is considered environmentally friendly. It is of natural origin (from wood) and undergoes biological degradation (though slowly). It has low toxicity to organisms – it is not harmful to fish or plants at typical application concentrations. In large amounts, it may reduce oxygen levels in water (as bacteria consume oxygen during its decomposition), but overall its environmental impact is minimal, especially compared to alternative chemicals, and it is considered more environmentally friendly than many alternatives.
How does sodium lignosulfonate differ from calcium lignosulfonate?
The difference lies mainly in solubility and form. Sodium lignosulfonate is highly soluble in water and is often supplied as a liquid concentrate or soluble powder. Calcium lignosulfonate is less soluble – usually sold as a partially soluble powder, commonly used in animal feed or road surfacing. Functionally, they serve similar purposes (plasticizers, dispersants), but the sodium salt is preferred where full solubility or liquid form is required.