K. Nikolova, S. Bratkova, Anatoliy T. Angelov, P. Genova, R. Ivanov, A. Štefanová
{"title":"TREATMENT OF SULPHATES-RICH SOLUTIONS THROUGH ETTRINGITE PRECIPITATION WITH INDUSTRIAL REAGENTS","authors":"K. Nikolova, S. Bratkova, Anatoliy T. Angelov, P. Genova, R. Ivanov, A. Štefanová","doi":"10.58903/a14161833","DOIUrl":"https://doi.org/10.58903/a14161833","url":null,"abstract":"Mine wastewaters are often characterised with high concentrations of sulphates, heavy metals and increased electrical conductivity. It is mandatory for the industry to implement convenient treatment methods in order to reduce these parameters. The aluminium precipitation with the simultaneous formation of ettringite was chosen for laboratory testing as it is appropriate when the concentrations of sulphates have to be reduced– up to 300 mg/l according to the Bulgarian regulatory framework. In the present study synthetic waters were treated, as their composition was similar to that of typical mining effluents. Initially, the pH of the solutions was adjusted to 9.0 with Ca(OH)2 and thus the heavy metals precipitated in the form of hydroxides. Then, an aluminium source was added as Al-cement, industrial Na-aluminate or aluminium oxychloride. The best results in terms of sulphates and electrical conductivity decrease were obtained with Al-cement (69 – 100 % sulphates removal rate), but the quantities of the generated sludges were large, which raises the question of their proper disposal. With the industrial Na-aluminate the rate of removal of sulphates was very low and with AlOCl it was 96%. However, the use of both reagents showed an increase in the electrical conductivity of the treated solutions.","PeriodicalId":239226,"journal":{"name":"SUSTAINABLE EXTRACTION AND PROCESSING OF RAW MATERIALS JOURNAL","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126439561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rationalising the location and design of the waste dump in the case of open-pit mining","authors":"Dimitar Kaykov, Ivaylo Koprev","doi":"10.58903/a14161827","DOIUrl":"https://doi.org/10.58903/a14161827","url":null,"abstract":"The location for dumping the waste from the open-pit mine has a significant weight for the establishment of the waste treatment costs. According to the constructive parameters of the waste dump and the terrain’s characteristics, the volume of the affected area is determined, in relation to the waste volume generated from the exploitation of a mineral deposit. In order to optimise the waste dump’s location and its constructive parameters, a number of alternatives have to be taken into account. These alternatives have to be technically plausible, as well as their safety factor must be satisfactory. Based on the considered alternatives, the optimisation problem can be defined so that the optimal solution provides the required capacity of the waste dump, as well as a minimal area of negative environmental impact and lowest operational costs.","PeriodicalId":239226,"journal":{"name":"SUSTAINABLE EXTRACTION AND PROCESSING OF RAW MATERIALS JOURNAL","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114775227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"CIRCULAR ECONOMY PRACTICES IN THE BULGARIAN RAW MATERIAL INDUSTRY","authors":"Vessela Petrova","doi":"10.58903/a14161834","DOIUrl":"https://doi.org/10.58903/a14161834","url":null,"abstract":"The circular economy, which promotes the responsible and cyclical use of resources, contributing to sustainable development is becoming more and more popular, especially in the European Union. The concept of switching from the traditional linear to cyclical consumption model leads to minimisation of waste and environmental pollution, and in this regard the New Circular Economy Plan is already in place. The great ambitions for changes in the industry are strengthened by the Green Pact (Green Deal). The publication presents an in-depth study of the literature on the subject, as well as the five business models through which, in practice, a circle is realised. It has been established that the literature in the context of the mining industry is extremely scarce, and the business models through which the processes in the industry are carried out are poorly studied. An up-to-date survey of 13 companies in the raw-material resources sector in Bulgaria is also presented, aimed at showing the extent to which they understand and apply the circular economy in their work. The results unequivocally prove that the concept is not new for the business.","PeriodicalId":239226,"journal":{"name":"SUSTAINABLE EXTRACTION AND PROCESSING OF RAW MATERIALS JOURNAL","volume":"286 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132584494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}