ﺑﺴﻢ اﷲ اﻟﺮﺣﻤﻦ اﻟﺮﺣﻴﻢ Sudan University of Science and Technology Faculty of Graduate Studies Development and Application of Cleaner Production in Rural Tanneries ﺗﻄﻮﯾﺮ وﺗﻄﺒﯿﻖ اﻻﻧﺘﺎج اﻻﻧﻈﻒ ﻓﻲ اﻟﻤﺪاﺑﻎ اﻟﺮﯾﻔﯿﺔ A thesis Submitted in fulfillment for the requirements of PhD degree in leather engineering By Faki Elamin Faki Mohammed Supervisor: Prof. Ibrahim Hassan Elamin Co-supervisor: Prof. Gurashi Abdullah Gassmelseed 2014 I Dedication I dedicate my thesis work to my loving parents whose words of encouragement have pushed me to success. I Acknowledgements The researcher gives his thanks and appreciation to the supervisors: Prof. G.A.Gasmelseed and I.H.Elamin for their help. Thanks are also due to technical staff of the incubator of the University of Sudan for Science and Technology for their permit to carry out the experimental work. Also thanks are due to Afroleather, Afrohide, Africa Tannery, Alfa & Beta for exporting and importing Ltd and Khartoum tannery for their support and help. Thanks are due to the graduate college of the University of Sudan for Science and Technology for giving me this opportunity to do my Ph.D. degree. II Abstract Sudanese rural tanning is an inherited craft. The methods and the indigenous materials employed by the rural tanners have remained unchanged for a long time. This is due to poverty, illiteracy, poor communications and lack of access to modern scientific technologies of leather production. As a result, the leathers produced by rural tanners are hard, crusty, liable to crack, tear. Moreover, the process period is long. The objective of the study is to investigate the possibilities of adoption of modern tanning methods to rural tanning with appropriate modifications (1) to speed up the process, (2) take out some of the hard manual work, (3) improve the quality of the produced leathers, (4) increase the production of the rural tanneries and (5) direct rural tanners toward cleaner production. For this purpose, a hand-operated drum was designed to carry out all wet processes through soaking to retanning. Modern tanning materials were introduced in all processes. Little amounts of chromium were used as a pre-tanning agent. The optimum amount of chromium was found to be 3% (based on the fleshed weight) which gave acceptable shrinkage temperature and good physical properties. After developing the tanning recipe and selecting the optimum chrome powder to be applied by rural tanneries, recycling of spent liquors was carried out to (1) minimize the environmental impact and to (2) reduce the production cost. Considerable savings on chemicals and water were obtained. Rural tanneries play a vital role in national economy and they have to be improved. Rural tanneries can create employment opportunities for a large number of people if attention has been paid for revamp and modification. III اﻟﻤﺴﺘﺨﻠﺺ اﻟﺪﺑﺎﻏﺔ اﻟﺒﻠﺪﯾﺔ ﻣﮭﻨﺔ ﻣﺘﻮارﺛﺔ ﻓﻲ اﻟﺴﻮدان. اﻟﻄﺮق واﻟﻤﻮاد اﻟﻤﺤﻠﯿﺔ اﻟﻤﺴﺘﺨﺪﻣﺔ ﺑﻮاﺳﻄﺔ اﻟﺪﺑﺎﻏﯿﻦ اﻟﺒﻠﺪﯾﯿﻦ ﻟﻢ ﺗﺘﻐﯿﺮ ﻣﻨﺬ زﻣﻦ طﻮﯾﻞ. وﯾﻌﺬي ھﺬا اﻟﻲ اﻟﻔﻘﺮ واﻻﻣﯿﺔ و ﺿﻌﻒ وﺳﺎﺋﻞ اﻻﺗﺼﺎل وﻋﺪم ﻣﻮاﻛﺒﺔ اﻟﺘﻜﻨﻮﻟﻮﺟﯿﺎ اﻟﺤﺪﯾﺜﺔ ﻓﻲ ﺻﻨﺎﻋﺔ اﻟﺠﻠﻮد. و ﻧﺘﯿﺠﺔ ﻟﺬﻟﻚ ﻓﺎن اﻟﺠﻠﻮد اﻟﻤﻨﺘﺠﺔ ﺑﻮاﺳﻄﺔ اﻟﺒﺎﻏﯿﻦ اﻟﺒﻠﺪﯾﯿﻦ ﺻﻠﺒﺔ وﻗﺸﺮﯾﺔ وﻗﺎﺑﻠﺔ ﻟﻠﻜﺴﺮ واﻟﻘﻄﻊ. ﺑﺎﻻﺿﺎﻓﺔ اﻟﻲ طﻮل ﻓﺘﺮة اﻟﻌﻤﻠﯿﺔ. ﻟﺬﻟﻚ ﺗﮭﺪف ھﺬه اﻟﺪراﺳﺔ اﻟﻲ ﺑﺤﺚ اﻣﻜﺎﻧﯿﺔ ﺗﻄﺒﯿﻖ اﺳﺎﻟﯿﺐ اﻟﺪﺑﺎﻏﺔ اﻟﺤﺪﯾﺜﺔ ﻋﻠﻲ اﻟﺪﺑﺎﻏﺔ اﻟﺒﻠﺪﯾﺔ ﻣﻊ ﺑﻌﺾ اﻟﺘﻌﺪﯾﻼت وذﻟﻚ(1) ﻟﺘﺴﺮﯾﻊ اﻟﻌﻤﻠﯿﺔ (2) واﻟﺘﻘﻠﯿﻞ ﻣﻦ ﺑﻌﺾ اﻟﻌﻤﻞ اﻟﯿﺪوي اﻟﺸﺎق (3) وﺗﺤﺴﯿﻦ ﻣﻦ ﺟﻮدة اﻟﺠﻠﻮد اﻟﻨﺘﺠﺔ (4) وزﯾﺎدة اﻧﺘﺎج اﻟﻤﺪاﺑﻎ اﻟﺒﻠﺪﯾﺔ (5) وﺗﻮﺟﯿﮫ ھﺬه اﻟﻤﺪاﺑﻎ ﻧﺤﻮ اﻻﻧﺘﺎج اﻻﻧﻈﻒ. ﻟﮭﺬا اﻟﻐﺮض ﺗﻢ ﺗﺼﻤﯿﻢ ﺑﺮﻣﯿﻞ ﯾﻌﻤﻞ ﯾﺪوﯾﺎ ﻻﺟﺮاء ﺟﻤﯿﻊ اﻟﻌﻤﻠﯿﺎت اﻟﺮطﺒﺔ ﻣﻦ ﻣﺮﺣﻠﺔ اﻟﺒﻠﻞ وﺣﺘﻲ ﻣﺮﺣﻠﺔ اﻋﺎدة اﻟﺪﺑﺎﻏﺔ. ﻛﻤﺎ ﺗﻢ ادﺧﺎل ﻣﻮاد اﻟﺪﺑﺎﻏﺔ اﻟﺤﺪﯾﺜﺔ ﻓﻲ ﻛﻞ ھﺬه اﻟﻤﺮاﺣﻞ. وﻛﺬﻟﻚ اﺳﺘﻌﻤﺎل ﻛﻤﯿﺎت ﻗﻠﯿﻠﺔ ﻣﻦ اﻟﻜﺮوم ﻛﻤﺎدة داﺑﻐﺔ اوﻟﯿﺔ ووﺟﺪ ان ﻧﺴﺒﺔ 3% (ﻋﻠﻲ اﺳﺎس وزن اﻟﺠﻠﺪ ﺑﻌﺪ ازاﻟﺔ اﻟﻠﺤﻤﯿﺔ) ﻣﻦ ﺑﺪرة اﻟﻜﺮوم ھﻲ اﻟﻨﺴﺒﺔ اﻟﻤﺜﻠﻲ ﻟﻠﺪﺑﺎﻏﺔ اﻟﺒﻠﺪﯾﺔ ﻻﻧﮭﺎ اﻋﻄﺖ درﺟﺔ اﻧﻜﻤﺎش وﺧﺼﺎﺋﺺ ﻓﯿﺰﯾﺎﺋﯿﺔ ﻣﻘﺒﻮﻟﺔ ﻟﻠﺠﻠﺪ. ﺑﻌﺪ وﺿﻊ وﺻﻔﺔ اﻟﺪﺑﺎﻏﺔ اﻟﻤﻨﺎﺳﺒﺔ واﺧﺘﯿﺎر ﻧﺴﺒﺔ اﻟﻜﺮوم اﻟﻤﺜﻠﻲ ﻟﻠﺪﺑﺎﻏﺔ اﻟﺒﻠﺪﯾﺔ ، ﺗﻢ ﺗﺪوﯾﺮ واﻋﺎدة اﺳﺘﺨﺪام اﻟﻤﺨﻠﻔﺎت اﻟﺴﺎﺋﻠﺔ اﻟﻨﺎﺗﺠﺔ ﻣﻦ ﻛﻞ اﻟﻤﺮاﺣﻞ ﻣﻦ ﻣﺮﺣﻠﺔ اﻟﺒﻠﻞ وﺣﺘﻲ ﻣﺮﺣﻠﺔ اﻋﺎدة اﻟﺪﺑﺎﻏﺔ . وﻗﺪ ﺗﻢ ﺗﻮﻓﯿﺮ ﻗﺪر ﻛﺒﯿﺮ ﻣﻦ اﻟﻤﺎء واﻟﻤﻮاد اﻟﻤﺴﺘﺨﺪﻣﺔ. ﺗﻠﻌﺐ اﻟﻤﺪاﺑﻎ اﻟﺒﻠﺪﯾﺔ دورا ﺣﯿﻮﯾﺎ ﻓﻲ ﺗﻨﻤﯿﺔ اﻻﻗﺘﺼﺎد اﻟﻮطﻨﻲ ﻻﺗﮭﺎ ﺗﻘﻮم ﺑﺪﺑﺎﻏﺔ ﻋﺪد ﻛﺒﯿﺮ ﻣﻦ اﻟﺠﻠﻮد اﻟﺨﺎم. ﻟﺬﻟﻚ ﻻﺑﺪ ﻣﻦ ﺗﺤﺴﯿﻨﮭﺎ. ﺑﺎﻻﺿﺎﻓﺔ اﻟﻲ ذﻟﻚ ﻓﺎن اﻟﻤﺪاﺑﻎ اﻟﺒﻠﺪﯾﺔ ﯾﻤﻜﻦ ان ﺗﺨﻠﻖ ﻓﺮص ﻋﻤﻞ ﻟﻌﺪد ﻛﺒﯿﺮ ﻣﻦ اﻟﻨﺎس اذا ﻣﺎ وﺟﺪت اﻻھﺘﻤﺎم ﺑﺎﻟﺘﺤﺪﯾﺚ واﻟﺘﻌﺪﯾﻞ. IV Table of Contents Dedication…………………………………………………………………………………………..I Acknowledgements………………………………………………………………………………..II Abstract (English)………………………………………………………………………………...III Abstract (Arabic)…………………………………………………………………………………IV Table of contents…………………………………………………………………………………..V List of Tables……………………………………………………………………………………..IX List of Figures…………………………………………………………………………….X 1 Introduction…………………………………………………………………………………...1 1.1 Leather…………………………………………………………………………..............1 1.2 Tanning………………………………………………………………………………….2 1.3 Modern tanning method…………………………………................................................3 1.4 Sudan leather industry………………………………………………………...................4 1.5 The study problem………………………………………………………........................5 1.6 The importance of the study…………………………………………………………….5 1.7 General objectives……………………………………………………………………….5 1.8 Specific objectives……………………………………………………………................6 1.9 About the study………………………………………………………………………….6 2 Literature review……………………………………………………………………...............7 2.1 Raw materials……………………………………………………………………………7 2.1.1 Structure of hides and skins ................. ……………………………………………7 2.1.2 Chemical constituents of hides/skins .................................................................... 9 2.1.3 Types of raw materials ......................................................................................... 9 2.1.4 Quality of hides and skins .................................................................................. 10 2.1.5 Curing of hides and skins ................................................................................... 10 2.2 Pre- tanning operations………………………………………………………………...11 2.2.1 Soaking .............................................................................................................. 11 2.2.2 Unhairing and liming ......................................................................................... 12 2.2.3 Mechanical operations after liming..................................................................... 12 2.2.4 Deliming ............................................................................................................ 13 2.2.5 Bating ................................................................................................................ 13 2.2.6 Pickling ............................................................................................................. 14 V 2.2.7 Degreasing ......................................................................................................... 16 2.3 Tanning operations……………………………………………………………………..17 2.3.1 Chrome tanning ................................................................................................. 18 2.3.2 Basification ........................................................................................................ 23 2.3.3 Vegetable tanning .............................................................................................. 24 2.3.4 Alternatives to chromium ................................................................................... 30 2.3.5 Combination tannage ......................................................................................... 31 2.4 Post- tanning Operations……………………………………………………………….35 2.4.1 Neutralization .................................................................................................... 37 2.4.2 Leather Dyeing .................................................................................................. 38 2.4.3 Fatliquoring and oiling ....................................................................................... 43 2.4.4 Drying ............................................................................................................... 48 2.5 Finishing operations……………………………………………………………………48 2.5.1 Mechanical Finishing operations ........................................................................ 49 2.5.2 Finishing materials ............................................................................................. 49 2.5.3 Pigment finishing ............................................................................................... 50 2.6 Cleaner production in leather industry…………………………………………………50 2.6.1 Cleaner technology in soaking............................................................................ 51 2.6.2 Clean technology in liming and unhairing .......................................................... 52 2.6.3 Clean technology in deliming and bating ............................................................ 52 2.6.4 Pickling and chrome tanning .............................................................................. 53 2.6.5 Vegetable tanning .............................................................................................. 54 2.7 Planning a rural tannery………………………………………………………………..55 2.7.1 Site .................................................................................................................... 55 2.7.2 Size.................................................................................................................... 55 2.7.3 Basic sections .................................................................................................... 56 2.7.4 Machinery .........................................................................................................