Category Archive : Technical Support

Potassium lignosulfonate

About Lignosulphonate

Lignosulphonate is an organic substance binding the cells, fibres and vessels which constitute wood and the lignified elements of plants, as in straw. After cellulose, it is the most abundant renewable carbon source on Earth. Between 40 and 50 million tons per annum are produced worldwide as a mostly non commercialized waste product.
It is not possible to define the precise structure of lignosulphonate as a chemical molecule. All lignosulphonates show a certain variation in their chemical composition. However the definition common to all is a dendritic network polymer of phenyl propene basic units.
There are two principal categories of lignosulphonate: those which are sulphur bearing and those which are sulphur-free. It is the sulphur bearing lignosulphonates which have to date been commercialized. These include lignosulphonates (world annual production of 500,000 tons) and Kraft lignosulphonates (under 100,000 tons p.a.). Due to the lack of suitable industrial processes, the sulphur-free lignosulphonates are as yet non-commercialized.
As a natural and renewable raw material, obtainable at an affordable cost, lignosulphonate’s substitution potential extends to any products currently sourced from petrochemical substances. The areas in which lignosulphonate is applicable include:
1) Multy-polarity related products
Lignosulphonate contains both hydrophilic and hydrophobic groups. Specific treatments can strengthen either characteristic for particular applications as in emulsions and dispersants.
2) Materials
Binders, thermoset, etc. Lignosulphonate is a natural branched and crosslinked network polymer which lends itself to use in materials.
3) Agriculture
Lignosulphonate and lignosulphonate derived products play an important role in the formation of soils and in plant and animal nutrition.
4) High purity / value applications
High purity support materials or active substances: lignosulphonate can be used as support materials for food and cosmetic applications comprising gels or emulsifiers; specially prepared lignosulphonates are suitable as an active substance with anti-oxidant, anti-bacterial and anti-viral properties. These qualities have already been explored and could play an important role in the future.

sodium lignosulfonate

Sulfonated modification of lignosulfonate

At present, the source of most sulfonated modified lignosulphonate products which at home and abroad is main abtracted from modified sulphite paper pulping waste liquor and alkaline papermaking pulping black liquor. Compared with alkaline papermaking pulping black liquor lignosulphonate product,sulfite method Paper pulping waste liquor of the modified products have the better Water-soluble, dispersion, surface active. the sulphite paper pulping waste liquor sulfonation modified is a kind of practical method . the sulphite paper pulping waste liquor sulfonation modified, is generally used in high temperature sulfonation method.make the lignosulphonate reaction with Na2SO3 under 150 ℃~200 ℃.,Introduction of sulfonic group on lignosulphonate side chain, to obtain the better water-soluble products.

Ma Tao etc.put forward the sulfonated test conditions: dosage of Na2SO3 is 110 mmol/g~610 mmol/g,the mass ratio of NaOH and Na2SO3 is1:9, the reaction high temperature is 165 ℃, holding time of 5h. Sokalova etc. put forward that under the action of oxidant, Lignosulphonate free radicals sulfonation reaction can be in relatively low temperature degrees,Zhou Yong etc.put forward that In the reaction according to the mole ratio1:15 join Na2SO3, Oxidant FeCl3, adjust pH 9 ~ 12, reaction 2 h under 95 ℃ ~ 98 ℃,to be obtained the lignosulphonate.

In the process of synthesis of lignosulphonate phenol resin reaction, the methoxyl of Lignosulphonate aromatic nucleus obstruct the Hydroxymethyl polycondensation in the chain of adjacent C9. Under certain conditions, to take advantage of sulfur to methylation modification of lignosulphonate, in the original position of methoxyl group introduced phenolic base, In order to increase the reaction activity of lignosulphonate. Use of sulfide modified lignosulphonate instead of the 60% phenol can be synthesized the better performance Lignosulphonate phenol hydroxyl resin. the appropriate conditions of Sulphate lignosulphonate sulfur Chemical modification is sulfur mass fraction at 5%, Alkali mass fraction at 4%, reaction 15 min under 260 ℃, The modified lignosulphonate methoxyl matrix Volume fraction reduced from 18.81% to11.84%.

Calcium lignosulfonate

What is Lignosulfonate?

Lignosulfonates is brown amorphous powder. They have no odour and they are not hygroscopic. They form colloidal solutions or dispersions with water but are not soluble in organic solvents. Lignosulfonates are biopolymers; they are salts of lignosulfonic acid that has been formed when pulp is manufactured by the sulphite method. The lignosulfonates are of varied composition because the woods are different, the extent of the lignin degradation can be different and a different number of sulfonic groups can have been added. Lignin is a polymer with a most varied length and composition, a fundamental structure being hydroxyphenyl propane. It contains many phenolic rings and methoxy groups, the figure gives one example. The distribution of unpolar and polar groups, including the hydroxyl and sulfonic acid groups formed at the degradation, decides the properties of the particular lignosulfonate.

Lignosulfonates are precipitated as calcium salts from spent process liquid, black liquid, from sulphite plants by means of lime, 90-95 % of the lignosulfonate is gained. Sometimes sugar from the spent lye will occur as a pollutant. Lignin containing sulfonic acid groups can also be made from lignin won from black liquid from the sulfate process for pulping that is more common in Sweden and is then called sulfonated lignin. Such sulphate lignin has a more uniform composition than sulfite lignin.
World production of lignosulfonates is estimated to be about 800,000 tonnes and of sulphonated lignine 15,000 tonnes. In Sweden, lignosulfonates are produced at Domsjö.

Lignosulfonates are used because of their not particularly powerful surface-active properties. To enhance these properties lignosulfonates are sometimes derivated with long aryl amines or by ethoxylation. Lignosulfonate is possible to use as initial material to make vanillin.

Lignosulfonate is used in many processes and products and seems to be a chemical under considerable development. It works on the surface of particles, both in dry systems and in water solutions. In dry systems lignosulfonate forms a layer on the particle surface, thus increasing the particle size and making the particles bind together. In water solutions the hydrophobic parts of the molecules bind to the dispersed particle, while the hydrophilic part bind towards water and thus the particle is kept in solution. The largest use of this substance is as a cement additive where it binds to the surface of the cement particles and delays the absorption of water, which is the hardening. The additive also influences the structure of the hardened cement. This is also used in lead batteries where some tenth of a percent of lignosulfonate acts on crystallisation of the lead sulphate so that the battery gets a much longer life-time. Lignosulfonate is used as a filler and binder in ceramic tiles, resins to fibre boards, casting sand and in fodder pellets. A large use is for dust-laying on roads as well as in dusty processes within industry. Lignosulfonate is used as a dispersant in products like fodder, dyes and industrial cleaners. It is used in industrial management of slurry, where addition of the substance facilitates pumping and separation of water in e.g. concrete. Lignosulfonates also have complexing properties and are used in ppm-concentrations to prevent scaling in hot and cooling waters and to keep micro-nutrients in solution in liquid fertilizers.