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miquel

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  1. Slag after cooldown. Bloom on the right. Slag on the left. This is the tuyere minus 2 cm (3/4"). miquel.
  2. My apologies Mark, I remember you very well. Mark Green Publicado 24 de enero 2013 - 17:09 Was it a pain, to clean the slag out from the bottom of the smelter, after the smelt? One of the? mistakes we made was that we could not figure out a way out for the slag. It settled at a lower level than we thought it would. After removing the bloom and stopping the trompe, we could hear the slag bubbling at the bottom of the furnace. Part of the slag was in contact with the tuyere and there was some erosion in the tuyere at that spot. After the slag cooled down and solidified it was very easy to remove it. miquel.
  3. Thank you, Jan. Very generous of you. I am eager to try again and if I need your contribution I will let you know. In the meantime, next time will have a “paella” dish ready for you… miquel.
  4. Here is a graph bloomery operators should have some familiarity with..especially those of us who may want to shift gears during the process, Predominance.jpg What is missing is the conversion of Hematite to magnetite which I have in another book (which I cannot find right now). Hematite to Magnetite will happen even if the percent CO is not that high, but it does require some heat. The Kelvin scale has the same units as the Celsius scale Celsius= Kelvin minus 273 Zero K = absolute zero This wet paste of charcoal powder and very fine iron ore keeps coming up in the literature..in some of the historic methods when the author states "a little water" I assume he/she may mean " a little water" or may be meaning "a little water and clay mixture". In the case of the Catalan forge I am sure there was lots of clean water around and the former was intended. It is possible the paste of charcoal and iron ore was added to redirect the hot reducing gasses in the furnace and forcing them through area of the bed of mostly ore..if this creates a greater resistance to flow it would also slow down the burn rate (though that may not have been the primary intent). The nice thing about that paste is , when the water is gone and there is no cohesion left, the charcoal does not become a blocking mass but flows out with the hot gasses. Jan Charcoal fines, ashes and water. It’s likely that the theories are correct and we suspect so, but the behavior in a smaller scale furnace may be different. miquel.
  5. In the old Catalan forges a single bloom weighting 150 kg (330 lbs.) ?was made at a time. Any leftovers remained in place and became part of the next bloom. They operated the furnace six days a week in shifts of 12 hours each. Each shift made two blooms. Our next plan is to make two blooms in a row. miquel.
  6. In the old Catalan forges they used very finely chopped charcoal, even mixed with fines to slow down the burn rate in the foremost half of the furnace. We ruled out that possibility because our oven wasn’t as big as the originals and we were afraid of chocking the process. In the data that I have of the original operation, the air pressure increases progressively during the run. Nobody knows what unit of measure they used, they wrote as a “?“ but we can get an idea of the progression. An increase in the air pressure meant an increase in the operating temperature. At the beginning and for 10 minutes they used 18?. From minute 10 to 75 they used 8?. From minute 76 to 142 they used 10?. From minute 143 to 184 they used 14?. From minute 185 to 230 they used 16?. From minute 231 to the end they used 18?. In our experiment we increased the pressure when we noted that the charcoal column in the foremost half of the furnace started to diminish. miquel.
  7. We noticed significant differences in the burn rate and the yield in terms of charcoal burned per kg of bloom produced when comparing our data to that of the antique Catalan forges. Data from antique Catalan forge: ... Charcoal used 544 kg. ...Charging time 6 hours. Burn rate: 14.9 kg charcoal every 10 minutes. ... Ore 487 kg. ... Bloom 151.6 kg. Yield: 31.1% ... Charcoal burnt per kg of metal produced: 3.58 In addition to the above, in the old furnaces they added 100 liters of water. It is not clear why. May be to increase gas formation or to increase the temperature, or both. miquel.
  8. We did chopped the charcoal but we did not think that going smaller was necessary. What do you think? Chopping it to a smaller size will result in more loses to fines and dust. The size we have used seems to allow for good combustion.
  9. Experimental data from running the Catalan Forge. ... Preheat 3 hours. ... Charging time 4 hours. --- Charcoal: Initial charge 40 kg. Most of the combustion takes place near the tuyere. We added an additional 30 kg for a burn rate of 2.91 kg of charcoal every 10 minutes. --- Ore: 22 Kg of hematite and siderite. --- Bloom weight: 7.5 kg. ... Final yield: 34.09%. --- Charcoal consumption per kg of metal produced: 9.3 For a first experience, we are very pleased. In the next we hope to increase the ore by and additional 15 or 20 kg. miquel.
  10. The best about a new experiment is finding again something lost in time… miq<uel.
  11. The bloom is beautiful by itself. Sometimes I feel bad when I hammer it down. I think will keep this one as a museum piece… miquel.
  12. I am not sure we can rely on the tuyere placement after the rebuilt which only happened a few years ago from the ruins of the old shop. If I were to trust my intuition, I don’t think the current tuyere height is correct…
  13. I am glad you liked it. Mark. It will be interesting to compare notes if you go ahead and give the Catalan Forge ("Farga") another go. I am not using refractory bricks, I am using the cheapest regular bricks lined up with refractory mortar. That works just fine. In the old Catalan Forges,("Farga") they built the furnace against a corner of the building thus taking advantage of the walls to pile up the charcoal. We did not have that kind of set-up so we improvised the metal plates. This is a picture of the best rebuilt or restored Catalan Forge that I have seen. It is located in Andorra and called “Farga Rosell.” For the next smelts we plan to consolidate the bloom but for this one we were interested in keeping it in the original form. More later… miquel.
  14. Thank you for the comments. There are a few more questions that I need to answer and mistakes we made that will need to be explained. I would like to address those with some pictures too and I will need some time to posts those but I will hold no secrets other than the recipe for the paella. miquel.
  15. Greetings Sid. If you are in a position to travel to Barcelona we could even share one of our metallurgical ventures. You can contact me by PM. miquel.
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