Polynaphthalene Sulphonate Technology

Polynaphthalalene sulphonates are increasingly used as superplasticizers in admixtures to concrete. Main advantages of these additives include

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  • High workability of concrete, resulting in easy placement without reduction in cement content

  • High strength concrete with normal workability but lower water content

  • A concrete mix with less cement but normal strength and workability.

 

Especially important are these admixtures for high performance requirements in construction of bridges and power station barrages

 

 

 

Sunniberg Bridge  ©Tiefbauamt Graubünden

Other main applications of polynaphthalene sulphonates are in the preparation of emulsions and latices.

ENCO ENGINEERING in co-operation with a well established producer, GRUPPO CHIMICO DALTON, is now in a position to offer plants for the production of polynaphthalene sulphonates with an up-to-date, efficient technology.

THE PROCESS

The production process for polynaphthalene sulphonates is including the following reaction steps:

  • Sulphonation of naphthalene with sulphuric acid producing b-naphthalene-sulphonic acid
  • Condensation of b-naphthalene sulphonic acid with formaldehyde producing polymethylene naphthalene sulphonic acid
  • Neutralisation of polymethylene naphthalene sulphonic acid with sodium hydroxide

Depending on reaction conditions products with different characteristics are obtained.

 

PROCESS HIGHLIGHTS

The offered new process is giving the following main advantages:

  • Improved product quality, with lower content of free sulphates. Crystallization of sulphate during cold weather periods can thereby be avoided.
  • Improved colour, important especially in the application of products for preparation of latices.
  • Higher activity of the product
  • Lower raw material consumption, by reduction of sulphuric acid and correspondingly also reduction of the neutralisation agent required.

 

TYPICAL PLANT SIZE

A typical plant capacity for a polynaphthalene sulphonate production plant would be 6000 tons per annum dry product and 14'500 tons per annum liquid product.

 

PRODUCT CHARACTERISTICS AND APPLICATIONS

Additive for Concrete, Liquid

The product is useful in all processes where dispersion, precipitation, sedimentation, flocculation and floating problems occur, due to its particular characteristics:

  • Solubility and stability against strong or diluted alkalis
  • Solubility and stability against strong or diluted acids
  • Exceptional dispersing and wetting properties
  • Low foaming power
  • Stability against oxidation, reduction, high temperatures
Appearance limpid liquid
Colour dark brown
Brookfield visc., 20 °C 60 ± 10m Pa.s
pH at 20 °C 8.0 ± 1.0
Density at 20 °C 1.200 ± 0.010 g/ml
Expansion test-slump 23.0 ± 1.0 cm
Dry residue 40 ± 1.0 %
Sulphates 2.0 ± 0.20 %

Applications:

Fluidificant in the production of concrete and cement paste, allowing a reduction in the water/cement ratio, with the following advantages:

  • Better processing
  • Reduced processing time/increase of production
  • Increase of concrete stability

The product can also be produced into dry powder

Additive for Concrete with Low Sulphate Content

Appearance

limpid liquid
Colour

dark brown
Density at 20 °C

1.200 ± 0.010 g/ml
Brookfield visc., 20 °C

60 ± 10 mPa.s
Sulphates

0.6 ± 0.2 %
pH at 20 °C

8.0 ± 1.0
Expansion test-slump

23.0 ± 1.0 cm
Dry residue

40.00 ± 1.00 %

Additive for Polymerisation and Latex Production

The product is a stabiliser for emulsion of monomers and dispersion of polymers during synthesis, namely for SBR and NBR rubbers. Further it is widely used in latex compounding to prepare stable aqueous dispersions of sulphur, zink oxide, antioxidants, filters and pigments.

Appearance

limpid liquid
Colour

clear brown
Brookfield visc., 20 °C

35 ± 5 mPa.s
pH at 20 °C

8.0 ± 1.0
Density at 20 °C

1.2 ± 0.1 g/ml
Dry residue

45 ± 1 %
Sulphates

2.5 ± 0.2 %

Additive for Leather and Pigment Production

The product is a dispersing agent and protecting colloid. It is particularly suitable in all processes where different powders must be solubilized or dispersed in an aequous liquid. Acting as a surface tension distroyer it permits to obtain excellent rheologies, together with increased concentrations of solids. It has a high stability against alkalis, acids, oxidation/reduction, high temperature.

Appearance granular powder
Colour clear brown
pH in solution, 10%, 20°C 8.0 ± 1.0
Behaviour in water soluble
Gardner colour (1% sol.) 3.0

Applications in the following fields:

  • Dyeing of textiles and leather
  • tanning
  • paints field
  • paper field
  • rubber field
  • metallurgic and galvano-technics industry.

For more information send us an e-mail !

ENCO Engineering GmbH Switzerland enco@enco.ch