The Discussion Of Indigo Production Waste Recycling And Processing Technology

Indigo is a very important reducing dyestuff,and its feature is dyeing uniformity?Coloring faster and difficult to fade.Since it appeared,then it has been appiled widely,at the same time.It also brings some troubles-a mount of waste residue.Indigo waste residue with its high basicity,high chroma,the more organic matter,and the complicated composition becomes a kind of industrial waste that it is both harmful and difficult to treat.Once the indigo waste residue mainly was sold to small paper factory to remove the lignin,along with the small paper factory disappearing,indigo waste residue is urgent to process.There are much industrial waste residue when Indigo is producted,these waste residue mainly include residual organic matter and diatomite except sodium carbonate and potassium.there are many different kinds of organic matter,but the relative content of monomer is not high,and the recovery of monomer is difficult,so they have no recovery value;The main composition of diatomite is silicon dioxide which is not big harmful to the environment and its price is not high,also they don't have recycling value;the alkali component of Potassium and sodium relative content is high,and their recovery is easy,also it has very high collection value Therefore,this topic takes the recycling of potassium and sodium as the main target,First of all,indigo waste residue is conducted to remove the organic matter,then the waste residue happens the causticizing reaction to produce NaOH and KOH,finally They returns to the alkali fusion reaction of production process in certain proportion;This paper mainly discusses how the temperature and time to effect causticizing reaction,Finally potassium and sodium are separated and recycled.Through the research for indigo production process to raise a series of waste treatment process,and we discuss the process of the experiments and the results of the analysis.The main contents are as follows:?1?The Roasting oxidation is very useful to remove the organic matter,but for removing indigo waste residue there are a lot of kinds factors,we mainly discuss the influence of humidity?temperature and time of roasting.By the indigo slag roasting result of dry and wet materials : slag drying after roasting is good than direct roasting drying,and Dry roasting has good solubility,and the organic matter content is easy to measure,So this topic choose dry roasting method.the roasting conditions are that The indigo waste residue is dryed under 110? for two days,then roasted about 2 h under 600 650?.?2?The study recovers the mixed alkali of NaOH and KOH By the causticizingcondition,so that they are recycled,Appropriate causticizing condition is as follows : the concentration of waste residual is about 10%,the concentration of lime milk after digestion is 250 g/L,and causticizing temperature controls at around 95 ?,and causticizing time is about 4 5 h.?3?We use the ternary system phase diagram of Na₂CO₃-K₂CO₃-H2 O and KCl-NaCl-H2 O to achieve the separation of potassium and sodium.Thus the study design the respectively two kinds of recycling technology of Na₂CO₃-K₂CO₃ and Na₂CO₃-KCl,finally the recovery of Na₂CO₃ rate is 96.75%,and the recovery rate of K₂CO₃ is 56.09%,and the recovery rate of KCl is 96%,so the study realizes the separation and recycling of potassium and sodium.