Students from 5th to 11th grades in private and public schools in Costa Rica learnt about the chemical composition and crystal structure of clay mineral. The raw material used for ceramics contains primarily clay mineral, which crystal structure is based mainly on elements such as oxygen, aluminium, silicon, iron and magnesium, among others. The crystal structure of the clay mineral is arranged in layers with diversity of elements that can be responsible for the physical properties of the ceramics, such as colour and hardness.
For the group of students from 5th and 6th grades, they were asked to bring food or materials which contains high amount of one of the bases element of the clay mineral. So, first they learnt the chemical formula and name of the element and associated it with a fruit or material. Afterwards, they formed a layer of the crystal structure using the fruits or materials. Then, they were divided into many groups. Each group created a layer as the basis for the crystal structure. Finally, they associated the composition and the crystal structure with the physical properties of the ceramics, for example white cercamics are based on kaolinite that contains mainly silicon and aluminium. For the group of students from 7th, 8th and 11th grades, a combination of presentations and interactive activities were done with the students.
The students learnt chemical elements with daily, common food or materials. Below are pictures of the two activities done at the Braulio Carrillo School and two activities at the Liceo Rodrigo Facio Brenes High School in San José, Costa Rica.
I had a two-month stay at CNRS, Toulouse, France as part of my secondment. The purpose of this visit was to carry out kinetic experiments on barite as part of my research within the EU-MINSC project. Many experiments were done at different conditions using batch low and high temperature reactors and analyses were conducted with ICP-AES. This opportunity was a great chance for exchanging knowledge and getting experience within the applied geochemistry environmental. First, of all I am thankful for supervision from Dr. Eric H. Oelkers, whose guidance and support were very valuable and meaningful for the research. I have got also valuable training and support from the fellows from different networks: Ulf-Niklas Berninger from MINSC, Martin Voigt and Christian Grimm from CO2-REACT and Andrea Pérez from MetTrans; help and encouragement from experienced researches, such as Thomas Rinder and Aridane González González, from specialised technicians for operating the high temperature reactors and analytical techniques, namely Alain Castillo and Philippe Besson, and assistance from Clare Desplats. I had a really great, helpful team during my stay, which was delighted by a wonderful weather, nice environment, memorable Friday’s wine and the daily, traditionally coffee-tea drinks after lunch!!!
Personally, it is very hard to give suggestions for future fellows who want to do their secondments here, because it depends mainly on the purpose of the visit. The CNRS is, by no doubt, a great choice for doing both experiments and analysis on applied geochemistry researches.
pH measurement is a important parameter in controlling the acidity of the geothermal fluid. A low pH indicates acid fluid, which might enhance the corrosion of the pipes. pH-meters are instruments calibrated at a temperature different from geothermal fluid, so the geothermal fluid must be cooled to the same calibration temperature of the pH-meter to get an accurate results.
pH measurement of the geothermal fluid in situ must be first cooled by passing the separated geothermal fluid through a cooling tubing surrounding by cold water. The cooled solution is collected in a container, where the pH-meter is introduced to measure its value.
Here is an illustration of this measurement.
A thermal spring is composed of many reactive dissolved geothermal gases, which interact with minerals and groundwater leading to a rich ion and colourful solution. Sampling a liquid of this solution requires immediately filtration in situ, for some analysis also acidification, at the sampling site in order to preserve the integrity of the sample and obtain accurate, representative analytical results.
Here are some illustrations of this process.
Furmaroles are areas composed of thermal springs and/or gas vents, where the magmatic materials release their gases, mainly carbon dioxide (CO2) and sulphur dioxide (SO2), which might mix with groundwater during their ascent to the surface.
Content of dissolved oxygen in geothermal fluid is very important to control the corrosion rate of the pipes. Because of the volatility of the oxygen, this compound must be fixed immediately in the sampling site after its collection. Then, the fixed solution must be titrated immediately to get accurate results.
Here are some illustrations of the fixation method and titration technique.
Dissolved oxygen is fixed immediately after collection with Mn(II) as manganese oxide (II), MnO2, which is a brown solid. The browner the solution, higher dissolved oxygen content in the sample. The brown solution is titrated immediately with a known concentration of tiosulphate in present of starch. The colour of the solution changes from purple to a light purple, when approaches to the end point of the titration.
During the ICC 2014, we had the opportunity to identify mineral scale formation in geothermal pipes, especially calcium carbonate. This mineral is formed inside the pipes because of the high content of calcium and dissolved carbon dioxide in the geothermal fluid. As the geothermal fluid ascents to the surface, the fluid might boil and causes the carbon dioxide partial pressure to decrease, so consequently the fluid might lead to supersaturation and calcite might precipitate.
During our hiking trip, we had also the opportunity to appreciate different minerals, rich in sulphur and iron oxide, as well as pyroclastic deposits from the eruption of the Eyjafjallajokull volcano in 2010.
Here are some pictures to appreciate the diversity of the minerals in Iceland!
The International Carbon Conference (ICC), carried out in Reykjavík, Iceland, between 25th to 29th August 2014, offered a unique opportunity to fellows from five different networks, specialized guests, academics and industries to network and to share knowledge and experiences among them. During two full days, we learnt a lot from many great presentations from experienced, prestigious specialists, geochemists, geologists, engineers and politics, others.
A field training course about sampling geothermal fluids and fumaroles, both liquid and gas phases, was organized for all the fellows from five different networks, such as CarbFix, CO2-REACT, MetTrans, MINSC and NORDICCS. We learnt about the different sampling preservation methods, analytical techniques for field titrations and all the principles behind the geothermal systems.
We also had the great opportunity to hike around the Thorsmork Natural Reserve, which is an area closed to the Eyjafjallajokull volcano, which erupts aggressively in 2010. We all know about the recent activity in the proximity of our area, but we all were so enthusiastic for this great adventure that most of us reached to the glacier and returned safe to the camp. We enjoyed the fantastic weather and the wonderful landscape along our hiking track.
Here are some memorable pictures of this great networking conference. Thanks all the ICC organizers and thanks Iceland for its amazing, unique nature!!!