Ocena ługowalności soli jako podstawa określenia technologii ługowania złóż soli

Abstract

Salt leachability assessments in selection of technology for leaching of salt depositsA b s t r a c t. Quantitative evaluation of salt leachability is still important technological parameter in applying professional simulation programs for industrial leaching. Designing and developing of various technologies of the rock salt well mining in OBRGSChem Chemkop for different deposit types and soluble minerals other than sodium chloride, the notion of leachability was extended by using more parameters for describing salt properties. Considering the dubious performance of complicated leachability tests, a relatively straight methodology was accepted for determining rates of salt leaching. The simulation program based on leaching rates was also created for various kinds of salts and was applied with success for several years. The methodology of quantitative evaluation of rock salt leachability applied by Chemkop gives the following set of data: 1) the salt leaching rates in the horizontal and vertical direction, 2) technological content of insoluble parts, 3) bulk density of rock. The tests may be performed in standard (20°C ) or different temperatures and under conditions of fresh water default and various concentrations of brine. Quantitative parameters of leachability were determined for salt rocks with very special structure and content to of insoluble parts up to 65% (Kasprzyk, 2001). It should be stressed that this set of quantitative leaching evaluations also appears correct in the case of soluble salts other than the rock salt. The process of designing technology for trona well mining involved evaluations of quantitatively leachability of this rock as well as tests of leaching properties of other soluble evaporates. A mineral known as glauberite appeared a significant challenge for this methodology. Specific approach developed for quantitative evaluations of glauberite leachability may be applied for rocks giving up a part of the mass to solution without loss of their physical shape. In accordance with the Chemcop methodology, qualitative tests should cover all the samples subjected to quantitative tests of leaching rates and those representive salt rock planned to be exploited by leaching. The results of quantitative analyses should be verified from the point of view of quality of surface of sample subjected to leaching. Samples displaying very deep and extensive leaching pits or signs loosening of their entire structure should be rejected from further analysis. Results of tests may be also influenced by behaviour of insoluble components at the contact with water. Sudden slaking of clay components may indicate the necessity to re-assess behavior of rocks in the course of well mining. Qualitative assessments of rocks surviving in terms and conditions of the leaching are similar to tests for rocks slacking. Such tests are connected with exposure on long-term contact with water, brine or lye (Kasprzyk, 2004). They make possible assessments of possibility of ”overleaching” of insoluble rocks layers in deposits with the complicated structure or occurrence of deformations, including cave-in in location of the designed. The tests also comprise salt rocks containing clay minerals, agglomerates, sandstones as well as rocks formed of other insoluble minerals (Kasprzyk, 2007). Qualitative tests, sometimes supplemented with quantitative studies, may facilitate decisions about the leaching technology in salt deposits