| With the development of fine chemicals and intermediate products,the amount of various by-product waste salts continues to increase.At present,most of the waste salt treatment and disposal methods lack economical and systemic methods.Therefore,appropriate methods are selected to harm these by-product waste salts It has become a major problem that the industry urgently needs to solve and implement resource utilization.The waste salt is taken from a chemical plant in Jiangsu to produce pharmaceutical intermediates.The phosphate in the ingredients has a high economic by-product value.A simple and effective method is used to recover the phosphate in the waste salt.The unusable part The solidification/stabilization treatment is performed to realize the recycling and harmless treatment of waste salt.The main research results are as follows:(1)The research first analyzes the composition of the inorganic and organic components in the waste salt.The mass fraction of phosphate in the waste salt is 69.3%-74.8%,and the impurities are mainly sodium chloride and N,N-dimethylaniline;Two methods,desolation and pyrolysis,were used to remove organic matter from waste salt.The effects of eluent amount and ratio,activated carbon amount and pyrolysis temperature on the removal effect of organic matter were investigated.The optimal condition is a ratio of 1 m L/g,the eluent ratio of methanol: ethanol is 4:6,and the dosage of activated carbon is 0.4% of the waste salt.The organic matter removal rate can reach 98.55%.In pyrolysis method,the temperature is 400℃,which is the optimal condition,and the organic matter removal rate can reach 98.18%.Considering the production process and economic cost of the plant,the elution method is used to treat the waste salt.Recrystallization at 5℃ can be obtained three times.Phosphate with a purity of more than 98%.The remaining salty waste liquid after solid-liquid separation is subjected to subsequent solidification and stabilization studies.Through the entire process of purification and recovery of waste salt,the cost of processing 1ton of waste salt is 174.24 yuan,0.61 tons of phosphate can be recovered,and the resource reuse of waste is realized.(2)Based on the difficulty of recovering the remaining salt-containing waste liquid,cement was used as a curing agent,and activated carbon and bentonite were used as additives to study the solidification and stabilization of the waste liquid.The impact of pollutant leaching rates,The effect of the leaching rate of cement is 1.8g/m L of cement,0.2% of activated carbon is added to cement,and 2% of bentonite is added to cement.Refer to "Solid Waste Leaching Toxicity Leaching Method Acetic Acid Buffer Solution Method"(HJ/T 300-2007)The maximum leaching rate of organics in acetic acid leaching agent is about 33.5%,the maximum leaching rate of chloride ions is about 31.0%;the maximum leaching rate of organic matter in deionized water leaching agent is about 25.4%,and the maximum leaching rate of chloride It is about 22.5%.The long-term environmental safety of the solidified body was evaluated by investigating the ability of the solidified body to combine chloride ions and long-term leaching performance.The results showed that the remaining waste liquid was cured with cement-bentonite-activated carbon,and the ability to bind chloride ions could reach 4.1.At 30 days,the leaching rates of chloride ions and TOC tended to be stable.Compared with the use of a single curing agent,the cured body maintained better stability,indicating that the combined action of the curing agent and the additive was harmless to the waste liquid containing salt.There is a certain application prospect in processing. |
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