Originaltext aus: InSolTherm Times
InSolTherm Times ist der einzige Solarthermie Newsletter Indiens. Vol. 1 Issue 10
Q1: What are the various types of anode rod used?
A. In the hot water storage tank industry the use of either Magnesium- or Aluminum anodes is common practice. Whereas the Al-anode is only available as extruded rod the Mg anode is available as extruded or cast version. Especially for big or complex tanks or application under difficult conditions, i.e. in hotels, restaurants, industrial applications the use of impressed current anodes such as the CORREX® or QGUARD® systems by MAGONTEC is state of the art technology and frequently used in Europe and North America.
Q2: What significant advantages does magnesium anode score over other metals?
A. Magnesium has a higher driving potential than Al or Zn. This means that the difference between the open circuit potentials of the anode and the cathode (= the steel structure) is higher. This leads to better protection level with Magnesium especially in difficult conditions such as low water conductivity. In many countries the use of Al and/or Zn anodes in potable water installations is forbidden for physiological reasons.
Q3: Hardness levels in India are typically desired is 300 mg/litre and permissible up to 600mg/liter. However several areas experience much higher values. Will magnesium be effective?
A. Magnesium will be effective under these conditions. MAGONTEC is specialized in development of customized protection solutions. This means the ideal composition of anode type, size, number of anodes and mounting position depending on the tank design.
Q4: Aluminum is the commonly used material as sacrificial anode in India. How would you defend magnesium a better choice?
A. Please refer to my comments in Q2. Further there is no risk of anode passivation with Mg. Especially in low conductivity water conditions there is a risk of anode passivation with Al-anodes. In this case Al-anodes lose their entire protections capability. This risk does virtually not exist with Mg-anodes.
Q5: Are the cost economics suitable when aluminum is compared to magnesium?
A. Costs of Mg-anodes are typically a bit higher than Al-anodes. However, in the global hot water storage market the market share of Mg-anodes is significantly higher (in pieces) than the Al-anode market share. This clearly shows that the industry values the savings of a long-lasting tank which results in lower warranty costs much higher than the small saving of Al-anode v/s Mg-anode.
Q6: What is the typical life of magnesium anode?
A. This question is very difficult to answer since it depends on many parameters, i.e. tank type, tank quality, water quality, tank design, anode size and quality, etc. A globally proven standard to the industry is the German DIN standard 4753, part 3 and 6. The minimum lifetime of a Mg-anode under the defined conditions is here given with min. 2 years.
Q7: Does magnesium offer any health benefits compared to other metals, when it comes in contact with hot water?
A. As already mentioned in 2b Zn and Al are considered as physiologically harmful in many countries. This does not count for Mg.
Q8: What about the global production situation of magnesium? How will it impact India considering it is not a major producer?
A. Mg anodes are made of Mg alloy AZ63 (cast anodes) or AZ31 (extruded anodes). These alloys are partly made from pure Mg and partly from other alloys which are for example used in the automotive industry. The amount of Mg-alloy used for cathodic corrosion protection in the hot water storage industry is fairly small compared to the amount of alloys used in the automotive industry. Though China is the dominant source for pure Mg we do not see any shortage at all regarding the availability of Pure Mg or other Mg alloys for the production of Mg-anodes.
Q9: What is your global market share as far as Solar Thermal Heating industry is concerned?
A. Magontec’s market share in cathodic corrosion protection of hot water storage tanks in Europe is approx. 60% plus and in China approx. 50% plus. In the North American market we hold a leading position in the field of impressed current anode systems, i.e. CORREX®.
Q10: What are the new happenings at Magontec?
A.
•The MAGONTEC group has made some significant steps forward over the last couple of years. Since November 2011 MAGONTEC is listed at the Australian Stock Exchange and we are now operating 5 Magnesium plants (2 in Europe and 3 in China) with a total capacity of approx. 78.000 mt.
•We are strongly focusing on high level R&D activities in order to continue to bring new technical solutions to the hot water storage tank market. A milestone has recently been the development and successful introduction of the new impressed current technology QGUARD® for emerging markets. We are strongly convinced this technology with an excellent price/performance ratio will become an important element in our future product portfolio
•In the automotive industry we have been very successful in launching new alloys for high temperature applications in cars. Famous car producers like Porsche, Mercedes, BMW, Volkswagen, GM, etc. have introduced these products.
•Our know-how in development of new alloys will help to further improve the existing anode alloys and increase lifetime of hot water storage tanks.
Q11: Would you share your future plans concerning India?
A. MAGONTEC considers India as one of the most important markets for our future development. The hot water storage industries as well as the automotive industry are growing segments in India. MAGONTEC is a leading player in Magnesium in both these fields and MAGONTEC is a growing company. We are an international company with a very long experience and strongly committed to expand our activities. For the time being we are monitoring the development of the Indian market in order to define the right market entrance strategy. MAGONTEC’s philosophy is to do things right and with best possible understanding of local needs. Over many years this has been proven the adequate approach for long-term relationship and we believe that the Indian customer wants to see this as well. I would like to thank InSolTherm Times very much for this opportunity to talk about cathodic corrosion protection in general and the use of Mg-anodes in particular.