BEHAVIOR PATTERNS OF ACRYLAMIDE COPOLYMERS IN CONCENTRATED SALT SOLUTIONS
A feature of enriching potassium ores is the process in a concentrated salt medium, which leads to a change in the properties of flotation reagents, particularly the flocculant reagent. In the present paper, the findings of studying the conformation state of the macromolecules of acrylamide copolymers in concentrated salt solutions and of their flocculation effects provided upon clay-salt sludge. The topicality of our study is determined by the fact that high requirements are set for flocculants in potash ores beneficiation processes, since flocculants must ensure the greatest possible fullness of clarifying the recycle lye (to prevent sludge from getting into the flotation cycle) and the highest level of the deposited sludge compaction (to reduce losing the liquid phase with wastes). Analysis of literature, performed in this paper, has shown that it would be reasonable to perform additional studies regarding the influence of salts upon the properties of aqueous polyacrylamide solutions and to identify the behaviors of polyacrylamide in concentrated salt solutions, which is important for potash industry. From laboratory tests, it is found that acrylamide copolymers demonstrate different behaviors in concentrated salt solutions: The compaction level of the macromolecules in a salt medium increases when transiting from ionic to anionic polyacrylamide copolymers. For cationic polymers, the concentration of electrolyte does not practically influence the globulization of macromolecules. It is found that changes in the conformation state of macromolecules influences upon the flocculating ability of the polymer towards clay-salt sludge: The higher the compaction level of macromolecules is in the salt medium, the higher the relative changes in the size of floccules is, when transiting to concentrated salt solutions. Anionic and non-ionic acrylamide copolymers are efficient, in terms of the resting contents of fine sludges in the flocculated suspension, and in terms of the final size of floccules. However, unlike cationic acrylamide copolymers, they do not ensure the high level of sludge compaction. To increase the flocculation efficiency, it is possible to use the compositions of acrylamide copolymers, which requires performing additional studies.