Milk of lime vs. saccharate liming
| MSI07P4246 | |
| Kong Win Chang, K. T. K. F. Lau Ah Wing, A. F. | |
| Milk of lime vs. saccharate liming | |
| ISSCT Processing Workshop: Cane Juice Purification Processes, 29 May to 1 June, 2006, Baton Rouge, Louisiana, USA | |
| Conference paper | |
| 2006 | |
| En | |
| En | |
| The objective of juice clarification is to produce clear juice of the lowest turbidity possible since this implies that fewer impurities would be carried over to the subsequent process streams. Experience in South Africa, Mauritius and Australia indicates that saccharate liming gives lower turbidity but higher mud volume than liming with milk of lime. One very important aspect that needs to be addressed when using lime saccharate is its preparation. Depending on the chemical and physical conditions under which calcium oxide reacts with sucrose there are three possible structures, namely, mono-, di- and tri-calcium saccharate. Of the three, mono-calcium saccharate is the most soluble and it is this form that should be used in lime saccharate clarification. While the stoichiometric ratio of sucrose to calcium for the formation of mono-calcium saccharate is 6.1:1, in practice a ratio of 7:1 is used thereby maintaining the slight excess of sucrose that is required for the reaction. In a study carried out in Mauritius, evaluating various liming techniques, namely fractional, intermediate and hot liming involving milk of lime and lime saccharate, the results indicated that intermediate liming was more effective (53 per cent ) than fractional liming with hot liming giving the lowest juice turbidity. In addition all saccharate liming produced much clearer juice (51 per cent ) than milk of lime methods. Moreover, handling milk of lime slurry in pumps, pipes, tanks and valves requires more frequent cleaning and constant maintenance than lime saccharate. Additionally, saccharate solutions show an improvement in the pH control of limed juices. Furthermore tests done on juices extracted at the Sugar Milling Research Institute (South Africa) and on all factory juices collected indicated that saccharate liming gave a better quality clarified juice in terms of turbidity, color and phosphate. However, it is reported in Australia that there is a higher calcium level in clarified juice obtained with saccharate liming and this may result in increased scale formation in evaporators when saccharate liming is used. The implications of all the results will be analyzed and discussed. | |
| sugarcane canesugar milling clarification saccharate liming liming milk of lime | |
| Mauritius | |
| Cane sugar manufacture | |
| Clarification and filtration | |
| 2007-02-23 | |
| En | |
| LST | |
| ST |