RU2430930C2 - Polycomponent flocculating systems for removing paint materials from recycled water - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a system of reagents for extracting paint materials from recycled water, based on acrylic, melamine, polyurethane, nitrocellulose, epoxy and alkyde film-forming agents and can be used in wood processing, machine building, motorcar and other industries. Disclosed is a flocculant consisting of (wt %) polyacrylamide (6-10), activating additive selected from aminotriazole, guanidine carbonate and semicarbazide (0.1-1.5), hydrazine hydrate (0.1-1.5) and water (the rest).

EFFECT: possibility of varying the structure of the obtained deactivated wastes of paint materials, which enables processing of paint material wastes for reuse or recycling with minimum expenses.

1 cl, 1 tbl, 4 ex

Description

The invention relates to the field of physico-chemical wastewater treatment of paint industries, in particular to a reagent system for extracting paint and varnish materials (LKM) from recycled water based on acrylic, melamine, polyurethane, nitrocellulose, epoxy and alkyd film-forming, and can be used in woodworking, engineering, automotive and other industries. The key characteristics of the flocculating system are the degree of purification of the circulating water, the period of flotation stability of the resulting paintwork materials, and the specific consumption. However, the possibility of varying the properties of the resulting paint and varnish waste is an important characteristic, since it makes it possible to obtain paint and varnish waste suitable for processing or easily utilized, which will provide an additional economic effect.

As a rule, the basis of flocculating systems are high molecular weight compounds, among which polyacrylamide and its derivatives are most often used ("Coagulants and flocculants in water purification processes. Properties. Preparation. Application." Zapolsky AK, Baran A.A. L. : Chemistry, 1987). In this case, the introduction of activating additives can increase the efficiency of high molecular weight compounds.

The invention is directed to the creation of a flocculating system that allows for a high degree of purification of recycled water, a long period of flotation stability of the resulting waste and low consumption to vary the properties of the resulting waste paint materials.

It is known to use a polyacrylamide-based flocculant treated with surface-active substances (SAS), which are hydroxyphobic polyhydric alcohol hydroxyalkylation products. The amount of polymer in a water-dispersible mixture is 12-15 wt.%, Surfactant 88-85 wt.% (US Patent No. 3634305, CL 260-33.4, publ. 1972).

However, the addition of these substances reduces the viscosity of the solutions of polyacrylamide, which complicates the transportation of flocculants to a functional destination, aggravates the mechanical grinding of polyacrylamide. In addition, quite large quantities of expensive and scarce surfactants are misused.

Also known is a flocculant based on polyacrylamide with the addition of a modifying agent - the product of the interaction of epichlorohydrin with salts of higher fatty acids C ₁₆ -C ₂₀ (USSR Author's Certificate No. 1595850, class C08F 220/56, C02F 1/56, publ. 1990, bull. No. 36).

However, this mixture must be dispersed in a solution of a grafted copolymer of polyacrylamide with carboxymethyl cellulose, the interaction takes place at a fairly high temperature of 60-80 ° C and a relatively low efficiency of the flocculant is achieved.

As a prototype, a flocculant known according to RU 2350635 C2, November 28, 2006, was selected. This flocculant is characterized in that urea is used in addition to polyacrylamide in its composition.

The disadvantage of this flocculant is the inability to vary the structure of the resulting flocculated particles due to the low flotation activity of urea, as a result of which the necessary period of flotation stability of the waste is not provided.

When using the inventive flocculating system, the technical result achieved by the invention consists in the possibility of varying the structure of the obtained deactivated waste of paintwork materials, which makes it possible to recycle paint and varnish for secondary use, or disposal at a low cost.

In addition, when using the invention, a high degree of purification of the circulating water is achieved, a relatively long period of flotation stability of the obtained paintwork materials at low reagent costs.

The technical result is achieved by the fact that the activating additives and hydrazine hydrate included in the flocculating system provide an adjustable density of the resulting LWM waste structures by varying the effective pore volume filled with air or neutral gases, which makes it possible to purposefully change the flotation stability and the state of flocculated LKM.

The invention is based on experimentally defined components of a flocculating system capable of significantly improving its properties.

A characteristic feature of the flocculating system is that due to the activating additives, the structure and, consequently, the density of flocculating coatings are purposefully varied, thereby ensuring that the coatings of waste coatings on the surface of the recycled water are technologically preset for a period of time. The speculative system contributes to an increase in the flotation rate of decontaminated coatings and provides a relatively long period of flotation stability, which increases the degree of purification of recycled water.

A speculative system was prepared as follows.

An aqueous solution of polyacrylamide was initially prepared at room temperature for 60 minutes with stirring. Then, an activating additive was introduced into the polyacrylamide solution with stirring, then hydrazine hydrate was added to the desired pH value.

The composition of the flocculating system, which allows you to vary the structure of the resulting decontaminated waste of paints and varnishes, can be illustrated by the following examples.

To obtain waste paint and varnish materials suitable for recycling, it is necessary to use a flocculant composition 1A or 1B:

Activating additive (0.15%) or (0.5%) for compositions 1a and 1b, respectively

Hydrazine hydrate (0.15%) Polyacrylamide (gel) (7%) Rest water

To receive the waste paint, disposed of at minimal cost, it is necessary to use a flocculant composition 2:

Activating additive (1.5%) Hydrazine hydrate (1.5%) Polyacrylamide (gel) (10%) Rest water

The above examples do not exhaust all possible compositions of the flocculating system using the claimed activating additives.

The results of the treatment of water containing coatings of LKM particles developed by flocculation systems are presented in the table (as part of 1a, the activating additive is aminotriazole, as part of 16, the activating additive is semicarbazide, and as part of 2, the activating additive is guanidine carbonate).

Table The degree of purification,% The period of flotation stability, h The proportion of recoverable waste from the surface of the water,% Composition 1a 99 40 99 Composition 1b 99 42 99 Composition 2 98 fifty 98 Prototype 98 one 80

The table shows that with a high degree of purification of the circulating water, the prototype does not take into account the flotation stability of paint and varnish waste, in connection with this, the real proportion of automatically removed paint and varnish wastes from the water surface is actually lower than the specified degree of purification, which was established by us on a pilot installation simulating the operation cleaning systems for paint production.

Claims (1)

A flocculant comprising polyacrylamide, an activating additive, water and hydrazine hydrate, characterized in that, in order to increase the efficiency of the flocculant, an additive from the group of aminotriazole, guanidine carbonate, semicarbazide is selected and hydrazine hydrate is introduced in the following ratio, wt.%:
Activating additive 0.1-1.5 Hydrazine hydrate 0.1-1.5 Polyacrylamide (gel) 6-10 Water Rest