*Written 9 July 2003 during the project - on a visit to a Chrome smelter.
Chrome Sex
What do Chrome Sex, Vibrators, big iron balls, and condoms have in common? Well, more than you may think, but not in the way you may think… Chrome Sex, I mean Six is a heavy dust that is produced as a result of slag – a waste by-product of smelted chrome.
We discovered this when we went on a tour at the Tubatse Works – one of the chrome mines in South Africa - nestling in the Steelpoort Valley. It is also the eleventh and last site to go live with the GSAP project at BHPBilliton.
Rules is rules
So we managed to arrange a tour for all the trainers who were keen to see what actually happens on a chrome plant - in other words, they wanted to see if what they had trained the 10 000 people was correct.
The day of the tour came, and we all went and waited like children for a school trip. We were guided by a Plant Maintenance Super User who is obviously very proud of Tubatse, and his job. He whisked us around the plant in a kombi answering most of our questions, and showing us some very interesting things along the way. He answered most of the questions that were straight forward, and but was a bit slippery on some relating to Rand values, exact tonnages, profit margin, and who owns the mineral rights. Also, was very vague around the slag dumps that were different colours…
On the day of the tour we were reminded about the rules:
· No cameras
· No cameras
· No cameras
· No tape recorders
· Oh yes, comfy shoes, clothes, and safety or sun glasses
Kinda makes you think they want to hide something ‘eh?
In fact, the no camera rule applies specifically for safety reasons – all photos must be “sanitised” before they are available for public consumption in order to promote correct use of safety equipment etc. Or so they say. Luckily I am not a conspiracy theorist.
Personal safety equipment was not issued to us, and nor did we have to attend a safety briefing as we were not actually going to be walking anywhere. We were driven around the smelter like guests of honour – negating the need for a PPE (personal protective equipment) or any other safety requirements. One of our colleagues was pregnant at the time, and they were quite hesitant to have her along in case the heat from the furnace caused her any problems.
Safety is definitely a big priority at the plant.
Heavy Metal
We piled into the kombi and our tour began. We were not allowed to open any windows without wearing glasses (unless you sat on the side where the window pane was broken), and were told to be on the look out for trucks carrying heavy metal. This is neither the music, nor the web programme, but a truck hauling red hot metal which is to be dumped. We did drive behind one, and it looked as if the truck itself were glowing. I think you could get quite a nasty burn from that!
Lucas Potgieter et al
We started at the train track where the piles of raw material are brought in. Lucas Potgieter brings the chrome in his big green and gold trucks (now there is a drug reference!?!) to the site where they are sorted and stacked in huge piles in the day bunkers. Contrary to popular belief Lucas is not an actual person but a trucking company that delivers the chrome to the smelter once it has been dug out of the ground. Those of you who have driven out to Tubatse will know the ones – they are the big trucks that drop the chrome onto our windscreens causing those irritating little pocks and cracks.
Day bunkers
The day bunkers are separate piles of ingredients that are used in the smelter. They include things like Chinese Coking Coal, Chrome, Quartz, and other secret piles of indistinguishable stuff. Also, at this stage, I would like to mention that we were not given a satisfactory answer as to why it is called a smelter and not a melter, but that is a story for another time.
Baking cookies
The smelter sends a “call” to the day bunkers causing a plate (called a vibrator) to vibrate under the relevant bunker causing the material to hop along onto a conveyor belt leading the stuff to a container. This container is some sort of enormous scale which weighs the ingredient and stops the vibrations when the required amount is in the container. The material is then conveyored into the smelter, and the next ingredient is called, and so on. When all the ingredients are there, the smelter then smelts the mixture and through some magical process I still don’t understand, chrome and slag come out the other end.
The technical details that I was able to gather include that the mixture is heated between 1700 and 2000 degrees in really big pots (see – this is really technical). There are two types of heating containers – pots and ladles. Evidently, the ladles are used for higher quality chrome product, and are treated more carefully, and looked after better than the pots. We saw a bunch of pots sitting on their heads out in the sun, packed on top of each other, and generally lying about, whereas the ladles were neatly stacked under a shelter. I still don’t really understand the difference between them, but the ladles are used to make chrome ingots which are large as a front loader
Chrome Dome
The big pots get a layer of chrome in them, and are regularly turned upside down and tapped to get the layer inside out. This is called the Hiawatha procedure. Not really.
The mixture in the pots (which is what we saw) is a red hot mixture of molten ferrochrome and slag. It is ferrous because of the high iron content in the chrome.
Also, strangely enough, although the slag floats at the top of the pot, it is always the first thing that comes out of the hole at the bottom of the pot. The slag is a waste-product, and unfortunately cannot be used for anything except building aggregate or as a concrete binder. Somehow the link between Chrome Six and slag was not covered, so we didn’t ask. The rest of the pot is about 21 tonnes of ferrochrome which is usually 43% pure chrome.
Back to the beginning again
Once the chrome has been melted (sorry, smelted), it is an even shiny black. But here’s the thing – once they have taken the small bits and made them big, they then crush them into small bits again. I wonder if that is what our guide meant when he said that it was a pity that they did not add any value, and that the product was only made more valuable once it was sold to someone else. Seriously, they are crushed and passed through a sieve and sold as dust, power, chunks, or rocks.
Apart from size, the chrome they sell is also classified by silicon content. The less the silicon, the harder it is to crush, but the more valuable.
This crushed chrome is stored again in other day bunkers, and then sent by train to wherever they are to be shipped or sold.
The slag is further refined in a chrome recovery process. Again, I am not clear on the technical details, but the chrome that comes out of this process is “shot” into a container which forms small, medium, or large chrome balls which look exactly the same as ironies – those metal marbles we all used to play with way back when.
The slag is then sent to a slag pile where it is stored and eventually sealed in concrete to avoid any contamination, even though they say there is no contamination from it. Erin Brokovic may disagree.
Other interesting facts
The way the pots work is to have that the mixture is melted by three electrodes arcing off each other and not the pot. The only problem with that was if the power goes off. If there is a loss of power, and consequently heat, it becomes difficult to get the electrodes out of the pot, and almost impossible to get the arcs going again.
In order to avoid this situation as much as possible – they have an agreement with Eskom. They have to let them know when they have planned power outages. I guess that you can negotiate this if you too pay R16 million each month.
Concrete feet – kapish?
The plant is busy reprocessing the old slag dumps to reclaim the final chrome from them, and in this process they have found all sorts of interesting things. They have found old cars, junk, and even skeletons. Well, maybe not skeletons, but when we asked if they found any bodies the tour guide answered with a comments about the next part of the tour, and a vague mumble about not being able to “prove those problems with the unions in those days”. I wonder if Jimmy Hoffa ever visited South Africa?
Did you know?
The greatest competition facing plants like Tubatse is reclaimable chrome scrap yards who currently hold 42% of the market.
Wave me goodbye
Our tour guide made a final wistful comment – that he was sad that they don’t actually add any value to the chrome, but that they sell the chrome to Japan who sell it back to us as stainless steel.
On the way out we were all counted again to make sure that we were all present and accounted for, given a condom, and asked to drive safely. Perhaps they should put an age restriction on this tour!
The Tubatse plant produces mostly product for export, and it is also the most profitable mine in the BHPBilliton group.
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