LLC "DUNIT"

Use of lignosulfonates

As an additive for mortars

Lignosulfonate-based additives are classified as hydrophilizing plasticizers. When using them, the stratification of the concrete mixture decreases, the consumption of cement decreases by 8-10%, the density of the concrete mixture increases and the rate of hardening slows down.
LST is used for plasticizing concrete mix, i.e. increasing its mobility from grade P1 to grade P3. As a side effect of the use of LST, there is a slowdown in the setting of the concrete mixture (up to 2 hours), which makes it possible to transport concrete over long distances or to lay massive concrete structures.
In the cement-raw material or concrete mixture are introduced
additives of lignosulfonates in the amount of 0.15-0.20%,
and superplasticizers must be introduced 0.5-2.0%
from the mass of dry cement. When superplasticizers are replaced with lignosulfonates, the strength of concrete increases by 20-25%, frost resistance is 3-4 times, and the cost of mixtures sharply decreases due to the addition of a small amount of lignosulfonates, which is associated with their adsorption on the surface of the solid phase.
The use of lignosulfonates reduces the moisture content of the raw sludge while maintaining its fluidity, which naturally increases the furnace productivity and reduces the specific fuel consumption for clinker burning.
With the use of intensifiers based on lignosulfonates, the productivity of grinding units increases and it becomes possible to replace expensive and scarce chemical products.
The use of technical lignosulfonates as an additive in the production of expanded clay gravel.
Technical lignosulfonates can be widely used as a corrective additive in the production of expanded clay gravel.
Expanded clay gravel is the most common artificial porous aggregate for lightweight and structural concretes, obtained by swelling clay by rapid firing in rotary kilns. Corrective additives introduced into the composition of clay raw materials make it possible to intensify the process of expanded clay formation, increase the swelling of raw materials, reduce the density and increase the strength of expanded clay.
The addition of LST sodium in an amount of 1–2% of the mass of absolutely dry clay raw materials allows to obtain other expanded clay granules with a reduced density of 0.38–0.43 g / cc.
Use of lignosulfonates as binders
In the manufacture of molding and core sands for iron, non-ferrous and steel casting, technical lignosulfonates are used as a binding material. At the same time, they replace some scarce and toxic materials: phenol alcohols, urea-formaldehyde and phenol-formaldehyde resins.
When using binders based on lignosulfonates, there is a decrease in the cost of suitable raw materials, an increase in the strength of the rods, a decrease in their crumbling to 0.05 - 0.08%, a decrease in temperature and a reduction in the time of thermal curing.
Lignosulfonates are supplied in liquid (LST) and powder form LST-P. Powdered lignosulfonates are produced from liquid lignosulfonates by drying in spray dryers. Composition by components (%): - sodium lignosulfonate (66-71), - sugars (10-12), - sodium salts of sulfurous acid (12-14). Water-soluble in any ratio. LST have universal properties of surfactants.

Lignosulfonates	Powdered technical lignosulfonate (LST-P)	Technical liquid lignosulfonate (LST)
Appearance	Flourish yellow powder	Dark viscous liquid
Mass fraction of dry substances,%, not less	92	50
Mass fraction of ash to the mass of dry substances,%	25	27
Concentration of hydrogen ions, pH, not less	4,6	4,5
Tensile strength of dried samples, MPa	0,6	0,6
Conventional viscosity, sec, not less	-	80
Mass fraction of reducing substances to the mass of dry substances,%	-	15
Density, kg / m3, not less	-	1280

According to the degree of impact on the body, technical lignosulfonates are low-hazard substances (hazard class 4 according to GOST 12.1.007)
Technical lignosulfonates do not possess skin-resorptive, local irritating and allergic effects. No cumulative properties have been identified.