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placed in the upper part of the During floation the solution is pp. [368][369][370][371].Cleansing the drain water in refractories factories to get rid of surface--active agents of the anion type --lignosulfonates --is a difficult and commonly encountered problem [1]. The methods described in [2, 3, pp. 20-58, 4, 5] which have been recommended for use with industrial wastes are laborious (adsorption on heavy-metal hydroxides, activated carbon, and settling), or are uneconomical (ion exchange, dialysis, reverse osmosis, etc. ).In recent years more and more investigators such as [6, 7, pp. 112-117] have shown a preference for flotation for cleansing drain water to remove surface--active substances. Previously [8] it was shown that the effectiveness of the flotation process can be greatly improved by adding certain inorganic colloids to the solutions of surfactive agents, and also salts capable of forming relatively insoluble compounds with the surfactive agents.The present authors studied the possibility of using the flotation method for separating lignosulfonates and including it in the overall drain-water purification scheme of a department producing heat-insulating inserts.Drain water from the Pervouralsk Dinas Factory and model solutions of lignosulfonates obtained by diluting sulfite lye were the objects of the investigation; the sulfite lye (SSB) came from the Solikamsk Cellulose-Paper Coml~ne. The properties of the drain water and the sulfite lye are reported in [1]. The concentration of the lignosulfonates in the drain water and the model solutions was 100-200 mg/liter.The flotation process is carried out in a glass column 700 mm high and 30 mm in diameter. The bottom of the column consists of a porous plate (Schott filter No. 4). The volume of solution poured into the column is 100 ml. Air is fed into the column from the bottom through the porous plate; the air consumption (70-80 cm3/min) is controlled with a rotameter. The foam that is formed is collected in a special receiver column where it is destroyed. The volume of liquid thus formed is measured. analysed for the concentration of lignosulfonates using the standard method [9,The effectiveness of the flotation process in separating lignosulfonates was assessed from the degree of their separation from the solution and the concentration coefficient 7 in the foam product which were calculated from the equationswhere C O and Cp are the concentrations of lignosulfonates in the solution before and after flotation, rag/liter; P and C F is the concentration of lignosulfonates in the foam product, rag/liter.

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One of the most complex problems arising in the creation of closed water-supply cycles in the refractory industry is the removal from the effluent of finely emulsified organic substances, particularly carbamide (urea-formaldehyde) resin, used as a binder in heat-insulating inserts.To solve such problems, in other branches of industry the flotation method is used [i, 2]. In most cases, before flotation treatment of the effluent coagulants (iron or aluminum sulfate) which promote coagulation of the oily phase and improve the purification conditions, are added to it [3, 4]. This method has serious shortcomings, due to the high consumption (100-120 mg/liter) of the reagents and to the difficulty of subsequent utilization of the separated organic substances.Previously [5, 6] we showed that these shortcomings can be eliminated by adding to the emulsion certain cationic-type surfactants (SUR) instead of inorganic reagents.This article gives the results of developments to establish the possibility of using cationic SUR to intensify flotation separation of carbamide resins from the effluent of refractory undertakings.The investigations were performed on effluent of the Seversk Dolomite Works, formed after compaction of heat-insulating inserts, and on model solutions of KSM-O3P carbamide resin, used in industry.Flotation of the disperse phase of the emulsions was performed in a laboratory machine with mechanical dispersion of air, and a cell capacity of 0.5 liters.The flow rate of air was 540 ml/min.The flotation time needed for the most complete separation of the emulsified resin was 15 min.The resin content of the effluent before and after flotation treatment was determined nephelometrically [7], and from the chemical consumption of oxygen (CCO) [8].The particle size of the disperse phase of the emulsions varied from 40 to 250 ~m. The potential of the particles at pH 7.0-7.5, corresponding to the effluent pH, was 15-20 mV.As cationic SUR --flotation activators --we tried chlorides of quaternary ammonium bases: alkyltrimethylammonium chloride (ATM) and alkylbenzyldimethylammonium chloride (ABDM) with a