Synthesis of an emerging morpholine-typed Gemini surfactant and its application in reverse flotation carnallite ore for production of potash fertilizer at low temperature

Abstract

Carnallite is a kind of high-quality source of raw material for the production of potash fertilizer (KCl) in industry. However, how to produce potash fertilizer sustainably at low temperature has always been a problem. In this work, we synthesized an emerging morpholine-typed Gemini surfactant, butanediyl-α, ω-bis (morpholino dodeculammonium bromide) (BM), which can be used to collect NaCl in reverse flotation carnallite ores in a low-temperature environment. We compared its ability to collect NaCl and carnallite with the monomeric surfactant 4-laurylmorpholine (LM) at low temperatures. The flotation test results indicated that BM has a stronger collecting ability for NaCl than that of conventional LM collector. At room temperature (25 °C), BM exhibits a forceful collecting function to NaCl and preeminent selectivity for carnallite. The recovery of NaCl ran up to 98.0% when the concentration of BM was 1 × 10−5 mol/L. Under the same condition, the flotation recovery using LM was only 39.0%. The recoveries of carnallite of the two were not more than 3.5%. When the environment temperature descended, the effect of BM for NaCl exhibited a stronger stable trend. The recovery with BM as a collector raised notably from 68.0% to 96.5% with temperature ranging from 0 °C to 15 °C. However, in the same scope of dosage and temperature, the recovery with LM collector only raised from 3.5% to 31.5%. At 0 °C, LM lost the vast majority of its collector performance, while BM still showed high performance.