Utilization Of Zinc Slag And Paste-like Amino Acids For Producing Composite Amino Acidic Zinc(?)complexes

As one of the necessary trace elements for plants and animals,zinc has been widely used in the various physiological processes of animals and growing process of plants,which lead to zinc as a common feed additive.Zinc usually exists in its inorganic forms as different additives.However,the absorption part is highly limited and most part is missed by discharge during the utilization process,suggestive of zinc element being not sufficiently utilized and further caused adverse effect to environment.As one of research interests,we have tried to prepare a product with easy synthetic route,low exploration cost and environmental friendly so as to satisfy the demand of feed additives.It has been known that there are lots of discarded keratin resources which could be utilized to hydrolyze obtain complex amino acids.The complex amino acids could chelate zinc ion effectively to form composite amino acidic zinc?II?complexes that may improve the absorption rate of zinc element.The recovery of keratin resources is of good benefits for the ecological and environmental protection.Based on the perspectives of raw material cost and environment protection,the utilization of zinc slag for preparation,purification and isolation of composite amino acidic zinc?II?complexes have been reported in this thesis,which may be divided into three parts:?1?The raw solution was analyzed by both physical and chemical methods,showing that the solution is mainly composed of?NH₄?₂SO₄,NH₄Cl,[Ni?NH₃?₄]Cl₂,[Ni?NH₃?₄]SO₄,[Zn?NH₃?₂]Cl₂,[Zn?NH₃?₂]SO₄ and large amount of free NH₃?H₂O.Based on the physical and chemical properties of the raw solution,the projects of isolation and purification were figured out.The cost of isolation process and profit of products were calculated,suggestive of obvious economic profits.The recovery significance of nickel ion was discussed.The residual amount of nickel and zinc ions in the wastewater meets the emission requirements of national environmental protection.There was no obvious ad-mix of the final isolated and purified products of Zn?OH?₂,ZnCO₃ and NiC₂O₄,of which each has a high purity of ca.98%after recrystallization.?2?The electrodialysis technology was used to separate salts from the sarcosine solution.The sarcosine solution containing sodium chloride was introduced to the desalination chamber driven by the DC current,and sodium chloride salt was separated by selective permeability of ion exchange membrane.The conductivities of amino acidic solution with different concentrations have been measured,showing the linear relations between conductivity and salt concentration.It has proved to be the change of the salt concentration resulting in the change of conductivity,further suggesting that the electrodialysis technology has a good effect method on desalination of amino acids.At present,this project has been industrialized with a stable processing capacity of 8 tons day by day,desalination efficiency of 99%,product recovery efficiency of 71.5%,energy cost of 26.4 Kwh/t and operation cost of CNY 311/t.?3?The composite amino acidic zinc?II?complexes were synthesized by reaction of complex amino acids and zinc slag separated from the catalyst waste solution.The product was characterized by UV-Vis,FT-IR and ¹H NMR spectroscopies.The chelating rate of the product was determined by EDTA titration method and atomic absorption spectrophotometer.In addition,the testing errors were reasonably calculated.The production and industrialization based on zinc slag and complex amino acids were evaluated,indicating that the technical process was practical,along with the material balance chart.It may provide evidence for the research of production of composite amino acidic zinc?II?complexes based on zinc slag and complex amino acids,which may reach a goal of recycling the waste and may be beneficial for economic profits and environmental protection.