I have just driven to Salt Rock for a long weekend. The road was busy and there were queues at the toll gates. The army taught me to hate queues, and I have already spent far too much of my life in them. I noticed that there were on average two unmanned toll booths per toll gate. The queues were therefore totally unneccessary.
I experimented with driving through the empty ones with the red crosses above them. At worst I had to drive over a road cone or two. At best I got a toll collector going hysterical, which I found quite gratifying.
South Africans are world renowned for their apathy and complacency, which is why we always get such bad service. Let's start doing something about it. Call it "affirmative toll paying". When you arrive at a toll gate and there are queues and some of the toll booths are unmanned, drive through. If enough people do it, the toll operators will be forced to spend that tiny bit more to pay enough staff to prevent queues.
This is the New South Africa, let's be positive in everything we do and make it a better place to live in.
Keramicalia have become the West Rand agents for Alusil gold pots. Alusil Refractories in Springs have a reputation for being the most innovative furnace builders in South Africa. Amongst their achievements is char plant built and comissioned in their factory, then dismantled and shipped overseas. Eddie Fullard invented the monolithic gold pot. He started with a brick lining in sections, and developed the technology step by step until the present complete unit with a prefired lime-free lining. Naas van Heerden, previously of Elgin and later Tugela Alumina, handles sales.
Product feature - KERAPOUR
Kerapour is a most unusual material. It combines most of what one wants from a refractory lining. It can resist molten metal contact, which is the downfall of most insulation materials. This can be demonstrated by making steel in a crucible of Kerapour. We use the "thermit" process, a dramatic chemical reaction between iron oxide and aluminium.
Incidentally, we repair slag pots by this process. Maybe we will use the subject for another newsletter.
Kerapour is a viscousbut free flowing, self-levelling material. Just add water, mix and pour.
Kerapour is frequently called on to do miracles. At Sappi's Enstra mill, a brick lining in their furnace had come loose. Here Kerapour was called on to fill the cavity and cement the lining, otherwise it would have to be re-bricked, and the shutdown would cost a fortune. I built a "swallow's nest" funnel out of Versimould Plug in the rather restricted doorway which was my only access to the crack leading to the cavity. I call this funnel structure a "swallows nest", because it is built up in layers similar to a swallows nest. It looks more like a swft's nest. Into this cup we poured Kerapour, and we poured and poured. Eventually we got half a ton in. The Kerapour leaked out of a few small holes which we plugged with Versimould Plug as they appeared. When the furnace was eventually rebuilt, we were able to determine how far the Kerapour had flowed; it had flowed for ten metres horizontally!
Some time later the same plant had a crack in the brickwork of a boiler arch. The air leaking through was causing premature ignition on the chain grate and destroying the breast plate and guillotine. A shutdown was already programmed to rebuild the arch at a cost of R30 000. I asked the engineer to give me just one day to try blocking the crack with Kerapour. We studied the drawings and found the appropriate points to introduce the Kerapour. We poured some in and sure enough it emerged through the crack over the whole length of the arch and sealed it. The boiler worked perfectly again.
Lance Pretorius of Natal Foundry Suppliers also did a neat "Red Adair" style repair on a gas leak at Sapref with Kerapour. A number of options were considered, and eventually Kerapour was chosen as the only safe option. It worked perfectly; a tribute to the properties of "cellular" insulation.
Cellular insulation is the answer to heat conservation in ladles. A backlining of Kerapour ensures a steel tight seal, as can easily be demonstrated in the thermit crucible test. Installation requires a casting former, which is not always available, so tiles are also made, for installation with Kerasil mortar. (Kerasil mortar is used because it is important to leave no gaps.) Tiles have proved themselves at Siltek and Scaw metals, and are now being offered for large ladles.
A basic version of Kerapour has now been developed at the request of some customers. Incidentally, we also have a basic insulating water-free mortar for use in contact with dolomite brick. It is particularly useful for preventing steel from getting behind the dolomite bricks, and helps to make breaking out easier.
Some readers want to know what a "contirution" is. Isn't it something to do with tying your body in a knot? Somebody reckoned it was either a printer's gremlin or the word processor reminding us to pay the installment.
Several readers want to know why we didn't tell them years ago about Multimould. Sorry, but that's the purpose of this newsletter. Two products down, about 50 to go.
Selling insulation by the kilogram has always been a hazardous occupation. Customers usually get the impression that good insulation materials are expensive. Furnace builders usually have more insight and immediately recognise a good insulation material as a bargain. To help evaluate new materials, I have developed a comparison which I call the "Heat containment cost factor". By definition it is the cost per square metre of a large furnace wall to reduce the temperature from 1000øC to 115øC. The average castable or brick has a thermal conductivity of around 1,3W/mK and a density of around 2,4g/cmþ. To reduce a furnace temperature from 1000 to 115øC we need 130cm of castable,to give us a K value of 100. One therefore requires 312kg per square metre, and say it costs R1 400/ton, the heat containment cost factor is R436.80. Heat containment cost factors for working linings are around this figure of 450 for aluminosilicate materials, and around for basic materials. Kerapour has a thermal conductivity of around 0,3W/mK, a density of 1,1g/cmþ and cost of R3 500/ton. This gives a heat containment cost of R25.41 i.e. it costs one tenth as much as normal materials to do the job of keeping the heat inside the furnace.
Let us take a simple example: Say we have a small furnace of 100mm square. We want a temperature of 1000øC inside the furnace and a cold face temperature of 115øC. To achieve this with a conventional castable or brick with a thermal conductivity of 1,3W/mK we would need a thickness of 130mm The total volume of material would therefore be 45 litres, weigh 108kg and cost R151. In Kerapour, we would need a thickness of 30mm, use 3,1 litres, weigh 3,4kg and cost R12, i.e. less than a twelfth of the price of normal dense materials. If you built the same out of basic brick, which would be daft, it would weigh 6 tons and cost 1000 times as much as Kerapour!
Note that the energy consumption drops drastically with good insulation and the speed of heating up increases drastically. Please let us do an exercise on your furnace to see if we can help. Fax us your dimensions, operating temperature and present lining design.