Improving the competitiveness of electrolytic Zinc process by chemical reaction engineering approach

This doctoral thesis describes the development work performed on the leachand purification sections in the electrolytic zinc plant in Kokkola to increase the efficiency in these two stages, and thus the competitiveness of the plant. Since metallic zinc is a typical bulk product, the improvement of the competitiveness of a plant was mostly an issue of decreasing unit costs. The problems in the leaching were low recovery of valuable metals from raw materials, and that the available technology offered complicated and expensive processes to overcome this problem. In the purification, the main problem was consumption of zinc powder - up to four to six times the stoichiometric demand. This reduced the capacity of the plant as this zinc is re-circulated through the electrolysis, which is the absolute bottleneck in a zinc plant. Low selectivity gave low-grade and low-value precipitates for further processing to metallic copper, cadmium, cobalt and nickel. Knowledge of the underlying chemistry was poor and process interruptions causing losses of zinc production were frequent. Studies on leaching comprised the kinetics of ferrite leaching and jarosite precipitation, as well as the stability of jarosite in acidic plant solutions. A breakthrough came with the finding that jarosite could precipitate under conditions where ferrite would leach satisfactorily. Based on this discovery, a one-step process for the treatment of ferrite was developed. In the plant, the new process almost doubled the recovery of zinc from ferrite in the same equipment as the two-step jarosite process was operated in at that time. In a later expansion of the plant, investment savings were substantial compared to other technologies available. In the solution purification, the key finding was that Co, Ni, and Cu formed specific arsenides in the “hot arsenic zinc dust” step. This was utilized for the development of a three-step purification stage based on fluidized bed technology in all three steps, i.e. removal of Cu, Co and Cd. Both precipitation rates and selectivity increased, which strongly decreased the zinc powder consumption through a substantially suppressed hydrogen gas evolution. Better selectivity improved the value of the precipitates: cadmium, which caused environmental problems in the copper smelter, was reduced from 1-3% reported normally down to 0.05 %, and a cobalt cake with 15 % Co was easily produced in laboratory experiments in the cobalt removal. The zinc powder consumption in the plant for a solution containing Cu, Co, Ni and Cd (1000, 25, 30 and 350 mg/l, respectively), was around 1.8 g/l; i.e. only 1.4 times the stoichiometric demand – or, about 60% saving in powder consumption. Two processes for direct leaching of the concentrate under atmospheric conditions were developed, one of which was implemented in the Kokkola zinc plant. Compared to the existing pressure leach technology, savings were obtained mostly in investment. The scientific basis for the most important processes and process improvements is given in the doctoral thesis. This includes mathematical modeling and thermodynamic evaluation of experimental results and hypotheses developed. Five of the processes developed in this research and development program were implemented in the plant and are still operated. Even though these processes were developed with the focus on the plant in Kokkola, they can also be implemented at low cost in most of the zinc plants globally, and have thus a great significance in the development of the electrolytic zinc process in general.

Computational studies for the design of process equipment with complex geometries

This study combines several projects related to the flows in vessels with complex shapes representing different chemical apparata. Three major cases were studied. The first one is a two-phase plate reactor with a complex structure of intersecting micro channels engraved on one plate which is covered by another plain plate. The second case is a tubular microreactor, consisting of two subcases. The first subcase is a multi-channel two-component commercial micromixer (slit interdigital) used to mix two liquid reagents before they enter the reactor. The second subcase is a micro-tube, where the distribution of the heat generated by the reaction was studied. The third case is a conventionally packed column. However, flow, reactions or mass transfer were not modeled. Instead, the research focused on how to describe mathematically the realistic geometry of the column packing, which is rather random and can not be created using conventional computeraided design or engineering (CAD/CAE) methods. Several modeling approaches were used to describe the performance of the processes in the considered vessels. Computational fluid dynamics (CFD) was used to describe the details of the flow in the plate microreactor and micromixer. A space-averaged mass transfer model based on Fick’s law was used to describe the exchange of the species through the gas-liquid interface in the microreactor. This model utilized data, namely the values of the interfacial area, obtained by the corresponding CFD model. A common heat transfer model was used to find the heat distribution in the micro-tube. To generate the column packing, an additional multibody dynamic model was implemented. Auxiliary simulation was carried out to determine the position and orientation of every packing element in the column. This data was then exported into a CAD system to generate desirable geometry, which could further be used for CFD simulations. The results demonstrated that the CFD model of the microreactor could predict the flow pattern well enough and agreed with experiments. The mass transfer model allowed to estimate the mass transfer coefficient. Modeling for the second case showed that the flow in the micromixer and the heat transfer in the tube could be excluded from the larger model which describes the chemical kinetics in the reactor. Results of the third case demonstrated that the auxiliary simulation could successfully generate complex random packing not only for the column but also for other similar cases.

CTQ process flow development and the impact for cost of quality

Tämä työ tehtiin Kone Industrial Oy:lle Major Projects yksikköön, laatuosastolle. Kone Major Projects yksikkö keskittyy erikoisiin ja suuriin hissi- ja liukuporras projekteihin. Työn tavoitteena oli luoda harmonisoitu prosessi hissikomponenttien laaduntarkkailua varten sekä tarkastella ja vertailla kustannussäästöjä, jota tällä uudella prosessilla voidaan saavuttaa. Tavoitteena oli saavuttaa 80-prosentin kustannussäästöt laatukustannuksissa uuden laatuprosessin avulla. Työn taustana ja tutkimusongelmana ovat lisääntyneet erikoisprojektit ja niiden myötä lisääntynyt laaduntarkkailun tarve. Ongelmana laaduntarkkailussa voitiin pitää harmonisoidun ja selkeän prosessin puuttumista C-prosessikomponenttien valmistuksessa. Lisäksi kehitysprosessin aikana luotiin vanhojen työkalujen pohjalta keskeinen laaduntarkkailutyökalu, CTQ-työkalu. Työssä käsitellään ensin Konetta yhtiönä ja selvitetään Koneen keskeisimmät prosessit työn taustaksi. Teoria osuudessa käsitellään prosessin kehitykseen liittyviä teorioita sekä yleisiä laatukäsitteitä ja esitetään teorioita laadun asemasta nykypäivänä. Lopuksi käsitellään COQ eli laatukustannusten teoriaa ja esitellään teoria PAF-analyysille, jota käytetään työssä laatukustannusten vertailuun case esimerkin avulla. Työssä kuvataan CTQ prosessin luominen alusta loppuun ja case esimerkin avulla testataan uutta CTQ prosessia pilottihankkeessa. Tässä case esimerkissä projektin bracket eli johdekiinnitysklipsi tuotetaan uuden laatuprosessin avulla sekä tehdään kustannusvertailu saman projektin toisen bracketin kanssa, joka on tuotettu ennen uuden laatuprosessin implementoimista. Työn lopputuloksena CTQ prosessi saatiin luotua ja sitä pystyttiin testaamaan käytännössä case esimerkin avulla. Tulosten perusteella voidaan sanoa, että CTQ prosessin käyttö vähentää laatukustannuksia huomattavasti ja helpottaa laadunhallintaa C-prosessikomponenttien tuotannossa.

Developing the Product Return Process of a Service Center With Lean Methods

Today lean-philosophy has gathered a lot of popularity and interest in many industries. This customer-oriented philosophy helps to understand customer’s value creation which can be used to improve efficiency. A comprehensive study of lean and lean-methods in service industry were created in this research. In theoretical part lean-philosophy is studied in different levels which will help to understand its diversity. To support lean, this research also presents basic concepts of process management. Lastly theoretical part presents a development model to support process development in systematical way. The empirical part of the study was performed by performing experimental measurements during the service center’s product return process and by analyzing this data. Measurements were used to map out factors that have a negative influence on the process flow. Several development propositions were discussed to remove these factors. Problems mainly occur due to challenges in controlling customers and due to the lack of responsibility and continuous improvement on operational level. Development propositions concern such factors as change in service center’s physical environment, standardization of work tasks and training. These factors will remove waste in the product return process and support the idea of continuous improvement.

Viral marketing in a Finnish medium sized gaming company: discovering, analyzing and building an improved management process for viral marketing campaigns, case: Nitrogames

The goal of this thesis is to build a viral marketing management framework for a Finnish medium sized gaming company. This is achieved by first finding and building a theoretical five step management process framework based on literature, analyzing current model and giving recommendations for the case company to develop its own management process. In addition, viral marketing research is still in early stage resulting this study to propose its own take on the definition in the theory part. Empirical part is based on qualitative interviews, campaign material and secondary sources and is aimed to find out and analyze the case company’s current viral marketing state and to give recommendations to it. The final outcome of the study is a general, theoretical management framework for viral marketing campaigns and specified recommendations for the case company.

Perspectives for using light quality knowledge as an advanced ecophysiological weed management tool

The current knowledge of light quality effects on plant morphogenesis and development represents a new era of understanding on how plant communities perceive and adjust to available resources. The most important consequences of light quality cues, often mediated by decreasing in red far-red ratios with respect to the spectral composition of incident sunlight radiation, affecting weed-crop interaction are the increased plant height and shoot to root ratio in anticipation of competition by light quantity, water or nutrients. Although the concepts related to light quality have been extensively studied and several basic process of this phenomenon are well known, little applications of photomorphogenic signaling currently are related to agricultural problems or weed management. The objectives of this review are to describe how light quality change can be a triggering factor of interspecific interference responses, to analyze how this phenomenon can be used to predict weed interference, to reevaluate the critical periods of interference concept, and to discuss its potential contribution towards developing more weed competitive crop varieties. Knowledge on light quality responses involved in plant sensing of interspecific competition could be used to identify red/far-red threshold values, indicating when weed control should be started. Light quality alterations by weeds can affect grain crop development mainly in high yielding fields. Unlike the traditional concept or the critical period of competition, light quality mediated interference implies that the critical period for weed control could start before the effects of direct resource (water, nutrients and available light) limitation actually occur. The variability in light quality responses among crop genotypes and the identification of mutants insensitive to light quality effects indicate that this characteristic can be selected or modified to develop cultivars with enhanced interspecific interference ability. Knowledge on light quality-elicited responses represents a new possibility to understand the underlying biology of interspecific interference, and could be used in the development of new weed management technologies.

Characterization Of Process Efficiency Improvement In Laser Additive Manufacturing

Laser additive manufacturing (LAM), known also as 3D printing, has gained a lot of interest in past recent years within various industries, such as medical and aerospace industries. LAM enables fabrication of complex 3D geometries by melting metal powder layer by layer with laser beam. Research in laser additive manufacturing has been focused in development of new materials and new applications in past 10 years. Since this technology is on cutting edge, efficiency of manufacturing process is in center role of research of this industry. Aim of this thesis is to characterize methods for process efficiency improvements in laser additive manufacturing. The aim is also to clarify the effect of process parameters to the stability of the process and in microstructure of manufactured pieces. Experimental tests of this thesis were made with various process parameters and their effect on build pieces has been studied, when additive manufacturing was performed with a modified research machine representing EOSINT M-series and with EOS EOSINT M280. Material used was stainless steel 17-4 PH. Also, some of the methods for process efficiency improvements were tested. Literature review of this thesis presents basics of laser additive manufacturing, methods for improve the process efficiency and laser beam – material- interaction. It was observed that there are only few public studies about process efficiency of laser additive manufacturing of stainless steel. According to literature, it is possible to improve process efficiency with higher power lasers and thicker layer thicknesses. The process efficiency improvement is possible if the effect of process parameter changes in manufactured pieces is known. According to experiments carried out in this thesis, it was concluded that process parameters have major role in single track formation in laser additive manufacturing. Rough estimation equations were created to describe the effect of input parameters to output parameters. The experimental results showed that the WDA (width-depth-area of cross-sections of single track) is correlating exponentially with energy density input. The energy density input is combination of the input parameters of laser power, laser beam spot diameter and scan speed. The use of skin-core technique enables improvement of process efficiency as the core of the part is manufactured with higher laser power and thicker layer thickness and the skin with lower laser power and thinner layer thickness in order to maintain high resolution. In this technique the interface between skin and core must have overlapping in order to achieve full dense parts. It was also noticed in this thesis that keyhole can be formed in LAM process. It was noticed that the threshold intensity value of 106 W/cm2 was exceeded during the tests. This means that in these tests the keyhole formation was possible.

Process modeling method for electric accessories manufacturing enterprise

The theoretical research of the study focused to business process management and business process modeling, the goal was to found a new business process modeling method for electrical accessories manufacturing enterprise. The focus was to find few options for business process modeling methods where company could have chosen the best one for its needs The study was carried out as a qualitative research with an action study and a case study as the most important ways collect data. In the empirical part of the study examples of company’s processes modeled with the new modeling method and process modeling process are presented. The new way of modeling processes improves especially visual presentation of the processes and improves the understanding how employees should work in the organizational interfaces of the process and in the interfaces between different processes. The results of the study is a new unified way to model company’s processes, which makes it easier to understand and create the process models. This improved readability makes it possible to reduce the costs that were created from the unclear old process models.

The role of network externalities in value creating process of the commercial web service for two-sided international markets

Network externalities and two-sided markets in the context of web services and value creation is not very well discussed topic in academic literature. The explosive rise of the Internet users has created a strong base for many successful web services and pushed many firms towards e-business and online service based business models. Thus the subject of this thesis, the role of network externalities in value creating process of the commer-cial web service for two-sided international markets is very current and interesting topic to examine. The objective of this Master’s Thesis is to advance the study of network externalities from the viewpoint of two-sided markets and network effects as well as describe the value creation & value co-creation process in commercial web service business models. The main proposition suggests that the larger network of customers and the bigger number of users the web service is able to attract, the more value and stronger positive net-work externalities the service is able to create for each customer group. The empirical research of this study was implemented for commercial web service, targeted to Russian consumers and Finnish business users. The findings suggest that the size of the network is highly related to the experi-enced value of the customers and the whole value creation process of commercial web targeted for two-sided international markets varies from the value creation for one-sided or pure domestic markets.

On-line determination of residual collector concentration in flotation process

Valuable minerals can be recovered by using froth flotation. This is a widely used separation technique in mineral processing. In a flotation cell hydrophobic particles attach on air bubbles dispersed in the slurry and rise on the top of the cell. Valuable particles are made hydrophobic by adding collector chemicals in the slurry. With the help of a frother reagent a stable froth forms on the top of the cell and the froth with valuable minerals, i.e. the concentrate, can be removed for further processing. Normally the collector is dosed on the basis of the feed rate of the flotation circuit and the head grade of the valuable metal. However, also the mineral composition of the ore affects the consumption of the collector, i.e. how much is adsorbed on the mineral surfaces. Therefore it is worth monitoring the residual collector concentration in the flotation tailings. Excess usage of collector causes unnecessary costs and may even disturb the process. In the literature part of the Master’s thesis the basics of flotation process and collector chemicals are introduced. Capillary electrophoresis (CE), an analytical technique suitable for detecting collector chemicals, is also reviewed. In the experimental part of the thesis the development of an on-line CE method for monitoring the concentration of collector chemicals in a flotation process and the results of a measurement campaign are presented. It was possible to determine the quality and quantity of collector chemicals in nickel flotation tailings at a concentrator plant with the developed on-line CE method. Sodium ethyl xanthate and sodium isopropyl xanthate residuals were found in the tailings and slight correlation between the measured concentrations and the dosage amounts could be seen.

The Role of networks in the internationalization process of Finnish design companies

Finnish design has attracted global attention lately and companies within the industry have potential in international markets. Because networks have been found to be extremely helpful in a firm’s international business operations and usefulness of networks is not fully exploited, their role in Finnish design companies is investigated. Accordingly, this study concentrates on understanding the role of networks in the internationalization process of Finnish design companies. This was investigated through describing the internationalization process of Finnish design companies, analyzing what kind of networks are related to internationalization process of Finnish design companies, and analyzing how networks are utilized in the internationalization process of Finnish design companies. The theoretical framework explores the Finnish design industry, internationalization process and networks. The Finnish design industry is introduced in general and the concept of design is defined to refer to the industries of textiles, furniture, clothing, and lighting equipment in the research. The theories of internationalization process, the Uppsala model and Luostarinen’s operation modes, are explored in detail. The Born Global theory, which is a contrary view to stage models, is also discussed. The concept of network is investigated, networks are classified into business and social networks, and network approach to internationalization is discussed. The research is conducted empirically and the research method is a descriptive case study. In this study, four case companies are investigated: the interior decoration unit of L-Fashion Group, Globe Hope, Klo Design, and Melaja Ltd. Data is collected by semi-structured interviews and the analysis is done in the following way: the case companies are introduced, their internationalization processes and networks are described and, finally, the comparison of the case companies is done in a form of cross-case analysis. This research showed that cooperation with social networks, such as locals or employees who have experience from the target market can be extremely helpful in the beginning of a Finnish design company’s internationalization process. This study also indicated that public organizations do not necessarily enhance the internationalization process in a design company point-of-view. In addition, the research showed that there is cooperation between small Finnish design companies whereas large design companies are not as open to cooperation with competitors.

Development of sales invoicing process in industrial services

The objective of this Master’s thesis is to find ways to streamline the invoicing process of the case company. In order to streamline the process, the bottlenecks and development areas of the present invoicing process needs to be identified. The bottlenecks are based on interviews made to personnel. The thesis also offers solutions to overcome the identified bottlenecks. The problem is the slowness of the invoicing process which should get rid off. The slow invoicing process causes delays in obtaining payments. There are many reasons for the slowness and inefficiency of the invoicing process. One of the biggest reasons is that the information systems are not deployed entirely. It causes additional work for everyone. Practices with the customers affect also to the smooth flow of invoicing. The contracts determine when the customer can be invoiced but also work approvals, missing work orders and customer’s own invoicing basis slow the process. The fastest and cheapest solution is to deploy the systems better and do things correctly. Thus duplicated work would decrease and resources would be saved. The work allocation should be modified and the practices with customer should be influenced too. In the future the meaning of IT should be highlighted and new devices exploited.