Study On The Recovery Of Flotation Agents By Foam Separation In The Anti-flotation And Cold-crystallization Methods Potash Extraction

Saline lake brine is the main source of raw materials for potash production,flotation is one kind of typical production process of potash extraction from saline lake brine.With the constantly increasing scale of potash production,The amount of flotation agent also increased rapidly.However,direct discharge of flotation tailings containing flotation reagents will can cause great pollution on the environment,the flotation reagents and their photodegradation products would affect the quality of the saline lake brine,they also have an impact on the production of high purity salt chemical products.Foam separation is a widely used and efficient separation method,which can effectively separate surface active substance.This paper studied three main flotation reagents,dodecyl morpholine?DMP?,sodium dodecyl benzene sulfonate?SDBS?,potassium laurate?PL?in separation of potash extraction from"reverse-flotation and cold crystallization"process by the foam separation.The influence law of four factors,the initial concentration of flotation reagents,the time of foam separation,the pH value of the system and the air inflow rate on recovery and enrichment ratio were investigated.The optimal separation conditions of flotation reagents for foam separation were determined by single factor experiment and orthogonal test,and the effects of inorganic cations(Na⁺,K⁺,Mg²⁺and Ca²⁺etc.)on the critical micelle concentration?CMC?and foam separation efficiency of flotation reagents were investigated.The experimental results show that:The optimum separation conditions of dodecyl morpholine?DMP?were as follows:initial feed concentration of DMP 1.37×10^-33 mol/L,the separation time 14min,pH value of solution 8,air inflow rate 8.00 L/min,and the recovery rate of DMP reached 91.02%.The optimum foam separation conditions of sodium dodecyl benzene sulfonate?SDBS?were:initial initial feed concentration of SDBS 1.40×10^-33 mol/L,the separation time 14 min,pH value of solution 8,the air inflow rate 6.00 L/min,and the recovery rate reached 94.79%.The optimum foam separation conditions of potassium laurate?PL?were:initial feed concentration of PL 5.50×10^-33 mol/L,the separation time 16 min,pH value of solution 8,the air inflow rate 6.50 L/min,and the recovery rate reached 80.45%.The concentration of inorganic salt cations plays an important role in the CMC of flotation reagents.When the concentration of inorganic salt ions increased gradually,the CMC of flotation agents decreased.When it increased to 200×10^-33 mol/L,the CMC value of flotation reagents decreased about 1/2.It can be seen that the influence of inorganic salt cation was Ca²⁺>Mg²⁺>K⁺>Na⁺.The concentration of inorganic salt cations plays an important role in the foam separation of flotation reagents.When the concentration of inorganic salt cations was low,the enrichment ratio of flotation separation for flotation reagents will decrease with the increase of the concentration of inorganic salt cations,recovery rate will increased with the increase of the concentration of inorganic salt cations.when the concentration of inorganic salt cations increased to 0.1 mol/L,The enrichment ratio and recovery rate of flotation agents gradually stabilized with the increase of the concentration of inorganic salt cations.And it can be seen that the influence capacity of inorganic salt cations on the foam separation of flotation reagents was Ca²⁺>Mg²⁺>K⁺>Na⁺.