CS232519B1 - Process for wet granulation of carbon black - Google Patents

Abstract

The invention provides a process for the wet granulation of carbon blacks by adding a granulating agent solution to the separated carbon black and then drying the resulting granules. The essence of this is that treated sulphite liquors with an increased CaO content and a content of 250 to 750 g / l are used as granulating additives, and the dosage of this solution is in the range of 1.3 to 12% by weight per tonne of granulated carbon black. The granulating additive can be modified by adding solutions containing simple and complex sugars in an amount up to BO% of the total weight of the polymerizing agent.

Description

The invention relates to a method of wet granulation of technical carbon black, carried out by adding a solution of a granulating additive to the separated carbon black and subsequently drying the resulting granules.

Carbon black granulation is still carried out either by a dry process, i.e. by gradually packing carbon black particles onto granule nuclei in a dry manner, or by a wet process, when a paste of carbon black with water is first formed, this mixture is agitated by continuous movement of the particles. In wet granulation, either pure water is used, or more often aqueous solutions are used, which improve the granulation process and increase the strength of the granules.

Dry granulation is used for so-called soft carbon black, while wet granulation is used for so-called hard carbon black, which can be granulated only poorly or not at all when dry. Wet granulation is much more energy-intensive, because the entire technology is much more complex and, above all, the added water from the granules must be subsequently evaporated. Products from the food and paper industries, such as molasses, vanisperse, ligrafo, etc., are used as granulation additives for wet granulation.

The disadvantage is the relatively high costs of providing these additives or the high biological activity of the materials used. Fermentation and putrefactive processes degrade the material by forming deposits and losing its beneficial binding properties, the already large dosage amount must be further increased, and during their dosage, difficult-to-solve operational problems arise due to the deteriorating homogeneity.

The above-mentioned shortcomings are eliminated by the use of the wet granulation method of technical carbon black according to the invention. Its essence is that modified sulphite leachates with an increased CaO content of 10 to 30 g/1 and a dry matter content of 250 to 750 g/1 are used as granulation additives, the most preferred being a dry matter content of 500 to 700 g/1. The dosed amount of this solution ranges from 1.3 to 12% by weight based on the amount of granulated carbon black, preferably in the amount of 2 to 5% by weight based on the amount of granulated carbon black. The granulation additive based on modified sulphite leachates can be modified by adding solutions containing simple and complex sugars in an amount of up to 80% of the total weight of the polymerization agent.

The advantage of the method according to the invention is primarily that a material is used that is readily available at low cost. The biological activity of the treated sulphite leachate is significantly lower than, for example, molasses, since the content of fermentable sugars is only 5 to 15%, based on dry matter, while the total content of simple and complex sugars including ligninsulfonic acid, i.e. the effective granulating component, reaches up to 65% by weight. Storage does not lead to deterioration of the granulating additive, nor does its dosing cause operational problems.

The following examples illustrate the practical use of the method according to the invention.

Example 1

During wet granulation of ISAF-type carbon black, modified sulfite liquors were added in an amount of 1.75% by weight, based on dry matter, with the following characteristics:

dry matter content ash content pentose content hexose content higher sugar content including lignin sulfonic acid pH

485g/1

70.2g/1

45.3g/1

50.0 g/l

296g/1

6.5

After drying the granules, the achieved strength of the granules, expressed as abrasion resistance, was 97.9% and the dust content in the granules was not higher than 3% by weight (ČSN 65Θ470).

Example 1 β ά 2

During wet granulation, modified sulphite leachates were added to HAF type carbon black in an amount of 2% by weight, based on dry matter, with the following characteristic properties:

dry matter content 520 g/1 ash content 74.3 g/1 content pentos 47.2 g/1 content hexos 52.1 g/1 higher sugar content including lignin sulfonic acids 305 g/1 pH 7.0

The achieved strength of the granules, expressed as abrasion resistance, was 99.2% and the dust content did not exceed 1.2% by weight (ČSN 658470).

Claims (2)

Process for wet granulation of industrial carbon black, by adding a solution of a granulating additive to the separated carbon black and subsequent drying of the resulting granules, characterized in that treated sulphite extracts having an increased CaO content of 10 to 30 g / l and a dry matter content 250 to 750 g / l, preferably 500 to 700 g / l, in an amount of 1.3 to 12% by weight, preferably in an amount of 2 to 5% by weight, based on the amount of granulated carbon black. Process according to claim 1, characterized in that the treated sulphite liquors are mixed with substances containing simple or complex sugars, preferably molasses, in amounts up to 80% of the total weight of the granulating agent before being used as granulating additives.