Ritva Tuunila

Effects of grinding parameters on product fineness in jet mill grinding

Abstract The influence of several grinding parameters on the product fineness in jet mill grinding was studied experimentally with a laboratory scale spiral type jet mill. The most significant variables in the jet mill grinding were feed rate, volumetric flow rate of grinding air and the height of an inside classification tube for grinding at constant pressure. Results showed that the height of the inner classification tube (vortex finder) is also a relevant variable in a spiral jet mill, and should be taken into account in optimising; the process. The finest product size was obtained with smallest material feed rate, highest grinding air flow rate and with the shortest classification tube.

Effect of continuous assessment on learning outcomes on two chemical engineering courses: case study

In this paper, the effect of continuous assessment on the learning outcomes of two chemical engineering courses is studied over a several-year period. Average grades and passing percentages of courses after the final examination are reported and also student feedback on the courses is collected. The results indicate significantly better learning results after the adoption of continuous assessment in the courses. Also student feedback suggests higher quality in teaching after the adoption of more activating teaching methods which compel students to study effectively throughout the course.

Development of Chemical Engineering Course Methods Using Action Research: Case Study.

This paper reports on the systematic development of a teaching methodology for two chemical engineering courses. The aim was to improve the quality of teaching to achieve expected learning outcomes more effectively. The development was carried out over a period of several years based on an action research methodology with data systematically extracted from student feedback and teacher reflection. Two new development targets were set every year based on teacher reflection and analysis of the data. Using action research as a development tool is an approach that can also be adopted in many other teaching fields. The results show that persistent development work leads to better learning outcomes and positive course feedback.

Is an accreditation seal worth the effort

Purpose – The purpose of this paper is to present observations of a EUR-ACE accreditation process in a Finnish university. The study demonstrates the effects (benefits, effort and resources required) of accreditation as seen by the university management and teaching staff. Design/methodology/approach – The material of the study was gathered by conducting an interview and questionnaire survey after the accreditation processes of six degree programmes at Lappeenranta University of Technology, Finland, in 2011. Findings – Besides certain shared views, the survey reveals some differences in opinions between the university management and the teaching staff: The management at all levels of the university valued the significance of accreditations somewhat higher than the teaching staff. Most of the interviewees found that accreditations have had an important effect on the curriculum work and thereby on the development of teaching and education. However, the effects on single courses were considered less signific...

Water Conscious Mining (WASCIOUS)

The main objective of the NordMin WASCIOUS project was to develop a technology concept for water conscious mining, where innovative water and tailings treatment technologies provide good-quality wa ...

Simulation of attrition bead mill and jet mill grinding

Abstract Fine powders of minerals are used in the paper and paint industry, and for ceramics. Grinding of minerals for fineness of few micrometers needed in these applications needs a lot of energy and therefore, an optimized control of grinding processes is very important to minimize the energy consumption. A good control system requires suitable simulation model of the process to be controlled. In this study, the suitability of the population balance model for simulation of attrition bead mill and jet mill grinding is tested, and new S-function for modeling of an attrition bead mill and a new C-function for the modeling of a jet mill is presented.