| China wool textile industry is one of the important pillar in the development of nationaleconomy. The annual total output and total sales are about10%of the national industry. However,as the industry profits grows, environmental pollution is becoming more and more serious. What’smore, it is seriously restricting the development of this industry, especially the sewage dischargeof wool scouring wastewater.In the wool industry, per ton wool produces several tons to ten tons of wastewater. The mainpollutants including lanolin and surface active agents cause serious problem of high content ofCOD in water. Its processing is not only difficult and but also demands high input cost. Yetlanolin has high economic value and it is widely used in cosmetics, pharmaceuticals, leatherand other fine chemical industries as a natural raw material.Currently, the technology of six slots washing wool scouring is widely used in the enterprises.Lanolin is recycled through centrifugal effect. The process is relatively simple. Nevertheless, therecovery rate is very low and it only accounts50%of the total lanolin. In addition, it is verydifficult to improve the recovery rate. Therefore, to further improve the recovery rate of lanolincan not only effectively improve the water quality, but also alleviates the pressure of thesubsequent processing and can produce huge economic value.This paper aims to improve the recovery rate of lanolin. First of all, the paper clears thedetection method of lanolin and standardized the application scope. Secondly, the paper hascompiled the on-spot investigation of the wool washing enterprises, in-depth understanding of theproduction process, property analysis of the waste water in each link and to seek further recyclinglanolin links. Finally, the suitable recovery process method has been explored thoroughly.The comparison of lanolin wastewaters from various industries was done by the methods ofultraviolet spectrophotometry, rapid emulsification and carbon tetrachloride extraction. The resultsshowed that UV spectrophotometry and rapid emulsification have high accuracy and they cankeep stability at low concentrations very well. Rapid emulsification method can realize thenon-toxic, rapid determination and it can also determine low concentration of lanolin content fromwaste water accurately and quantitatively. As for the wastewater with high content of lanolin carbon tetrachloride extraction is used which has high precision and accuracy, and it is a simpleprocess.Through field investigation of wool washing factory, we came to know that the wool washingfactory uses the technology of six slots wool washing and two stages centrifugal manner forlanolin recovery. The recovery rate is about50%and the rest of the lanolin with centrifugal watergoes back into the second slot, third slot. By material balance calculation, lanolin content in thewaste water system in the first oil centrifuge discharge and second tank intermittent drainage is thehighest. Which is more than1%. If they are fully extracted, the daily production will increase0.86tons. Nonetheless, the remaining part of lanolin content is low, does not have the advantages ofrecycling. Therefore, the first oil discharge and second slot machine drainage are the researchobjectives of recovery technology. The method of flocculation and extraction are determined onrecycling wool washing wastewater because the degree of emulsification is high and sedimentcontent is marvelous.The selection of flocculants, the affecting factors of flocculation settling velocity, theselection of extraction agent and the influence factors of extraction agent have been studied in thispaper. The results showed that when the PH was8, the temperature was40℃, processing thewastewater by the ratio of Al2(SO4)30.175g/L+PAM+4.5mg/L, COD can be decreased by94%,particulate matter decreased by95%, light transmission rate of95%, the settling velocity was0.5mm/s, the supernatant of lanolin content as low as625mg/L, the sediment was10.3%.Optimum extraction conditions were as follows: under the condition of35℃, using n-hexaneas extraction agent, compared to a quarter of settling sludge twice extraction, which can realize therecycling of lanolin wool washing wastewater, recovery rate was91.4%. The analysis of the purityof recycling lanolin showed that the extraction method can meet the requirements of the finishedproduct lanolin. The recovery rate of N-hexane was96.2%and the recovery of n-hexane can beused for further extraction.Using this technology can make the enterprise increase lanolin production300tons, netbenefit more than10million, recycling waste water above30000tons and can make lanolinrecovery rate increased from50%to57.8%. |
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