Acid in the Sea – or How I Missed My First Million

Article by Jimmy Hunter BSc CEng CSci

Durban and Holland: 1982

WHILE I was works manager for Chrome Chemicals in Durban, I was approached by a senior technical person from South African Titan Products (SATP). They were producing titanium oxide from ilmenite, using the old sulfate process, and produced a very large flow of dilute sulfuric acid, containing high concentrations of ferrous sulfate. I was horrified to learn that their method of disposal was to pump the acid into the sea off the Natal South Coast, not very far from a bathing beach!

The South African government was putting them under pressure to stop, but the alternative would be to switch to the new chloride process, which would need a great deal of capital.

The purpose of his visit was to explore the possibility of supplying the acid to us, since he had learned that our process used a lot of sulfuric acid. We were polite, but once we knew the composition of the effluent, we told them that we could not use the material in our process.

I spent many sleepless nights thinking about ways of using the waste sulfuric acid. Even after I left Chrome Chemicals and was working as an independent consultant, the thought of the acid-in-the-sea problem still haunted me. I later heard some apocryphal stories about fishermen catching stunted fish in the vicinity of the acid outfall.

Stranger things: Acid in the sea led to sleepless nights and apocryphal stories

Finally I came up with an idea which might solve the problem. Sulfuric acid had a very low value in South Africa because it was produced by many gold mines as part of their gold recovery from pyrites processes. Hydrochloric acid had a much higher value, for example for PVC manufacture. I came up with the following process (patent no.EP0065412A1):

The sulfuric acid would be partially neutralised with sodium sulfate.

H2SO4   +   Na2SO  --->    2NaHSO4       (1)

The sodium bisulfate could then be recovered by evaporation and crystallisation.

The sodium bisulfate was then reacted with common salt, sodium chloride, ie:

NaHSO4   +   NaCl  --->   Na2SO4  +  HCl      (2)

The crude sodium sulfate contained the iron as ferrous sulfate, and the HCl was given off as a vapour.

By then neutralising the solid with sodium hydroxide or sodium carbonate, the iron was precipitated as ferrous hydroxide, which could be sold as pigment grade, ie:

FeSO4    +   2NaOH  --->    Fe(OH)2   +    Na2SO4              (3)

The sodium sulfate could be recycled to reaction (1), and the ferrous hydroxide could be sold as a pigment. We can summarise the process in a block diagram:

The sodium sulfate can be recycled continuously, almost like a catalyst.

My precious!

How could I protect my invention? Since I had very little money, I could not take out a full patent. A patent agent whom I trusted suggested that I take out a provisional South African patent. There are other countries which offer a similar system, but it was very convenient (and cheap!) to do it in South Africa at the time.

The provisional patent provided protection for 12 months. If you decided to take out a full patent (say) in Britain during this period, you could do so and use the original filing date of the provisional patent as the invention filing date. The American company 3M (of Scotch brand Magic Tape etc) was the company with the largest number of new patents in the world. Their intellectual property department, responsible for all patents worldwide, was based in South Africa and always took out provisional patents there.

Once I had the patent, how could I sell the know-how? In 1982 there was no Internet (or Google) to help. I discussed the problem with a friend, Alan, who was an outstanding international trader. He offered to help, and suggested that we start with a big international company, for example Shell. At that time, Shell owned Billiton International Metals (BIM), which produced titanium dioxide in Holland, also with the sulfate process. What was their method for dealing with the waste sulfuric acid? Surprise, surprise! They pumped it into the sea! And the the Dutch government was putting them under huge pressure to stop.

Lunch and learn

Alan knew many of the people at Shell, and organised a lunch date with one of their top technical people, who had been seconded from Shell Nederland and was working in Johannesburg. The lunch turned out to be much more eventful than I expected! Henk, the Shell man, got excited about my technology, and suggested that Shell could hire me in Holland to develop it further. My friend Alan took exception to this, since he felt that Shell could take advantage of me. The two men jumped to their feet and started shouting at each other! I was a bemused onlooker, feeling like a top footballer with two managers fighting over him! Luckily, we soon smoothed things over and ended up on good terms and enjoyed the lunch. I went home, buzzing with excitement. However, my wife M, one of the world’s biggest pessimists, refused point blank to get excited!


For some months, I heard nothing, but was surprised when I got a phone call from a man from Shell Johannesburg. “How would you like to go to Holland, all expenses paid, and tell us more about your invention?” he said. Needless to say, I jumped at the chance. Apart from paying the air fare and providing accommodation, they also paid me a daily allowance which was equivalent to the travel allowance of a senior Shell executive. This was most welcome at the time!

A few days later, I was sitting in the business class section of a Boeing 727, bound for Schiphol airport. A chauffeur met me at the airport, and took me to their accommodation, a delightful cottage boarding-house. They arranged to pick me up for a meal at a wonderful trout restaurant, where I met some of the Shell people. They steadfastly avoided technical discussions, and the meal was relaxed and the food delicious.

The chauffeur picked me up the following day and took me to the impressive offices. I was led into an office with their lawyer. He explained that BIM was under pressure from the Dutch government, which had given them two years to find a solution to their acid-in-the-sea problem. Their technical people had identified 13 possible process routes to solving the problem. They were very logical, and were evaluating each route to choose the most economical one. The lawyer told me (with some relish) that my process was the thirteenth, ie final, option.

Suddenly I felt very much alone. I wished that I had some support, my own lawyer, perhaps? However, a few weeks earlier, Henk had helped me prepare my presentation, including converting all the financial figures to Dutch florins. The lawyer was surprised by the fact that I was talking about a positive cash flow for the process. All the other 12 processes would be expensive and have negative cash flows. I convinced him that they could make a profit using my process as part of their PVC operation, so we finally negotiated a royalty fee of £100,000/y over ten years, ie a total of £1,000,000. I signed the final contract with a happy heart!

I then spent two very pleasant days with two bright engineers, drinking litres of great coffee and discussing materials of construction, equipment design, etc so that they could do a preliminary design and estimate the capital cost.

I travelled back to Johannesburg along with two other passengers and six air hostesses in business class. It was an amazing feeling that my briefcase contained a contract worth a million pounds! M the pessimist was not as happy as me. She was sure that something would go wrong.

In the bag: one million pounds

Double Dutch

About five weeks went by, and I received a call from Shell’s Johannesburg office, offering a second all-expenses-paid trip to Holland. Again I was met at the airport, and booked into the guesthouse. I was taken to a restaurant for a very good meal, and the project was not discussed until the R&D boss dropped me off. He told me that he had good news and bad news. The good news was that 11 of the 13 processes had been rejected, leaving only my process and a Bayer process as the alternatives. The bad news was that the development of my process had hit a major obstacle. The purpose of my visit was to solve this problem so that they could continue to develop the process.

Needless to say, I did not sleep a wink all night, trying to imagine what the problem with my process could be. It turned out to be the very first step, in which the acid is mixed with solid sodium sulfate and the product is dried. The ratio of solid: liquid is key, as well as the amount of mixing power per unit volume. If these are correct, a free-flowing granular material is formed, which can be dried efficiently in a rotary or a fluid bed dryer. They had used conditions which resulted in a sticky material which rapidly blocked their dryer. I showed them how to solve this problem and indicated the required solid:liquid ratio for best results. This only took a few hours and I could leave them to their work.

Once again, I travelled back to Johannesburg with a light heart.

All in the timing

A few weeks later, I received the news that the Dutch government had changed its mind, and, although the German Bayer process was very expensive, both in capital and operating costs, it insisted on BIM using the Bayer process, since it did not need any development. Henk was furious, because he had put a great deal of effort into lobbying for my process, and he was convinced that it would be very profitable. BIM apologised to me, but their hands were tied. I went back to the exciting life of a process engineer working for a dynamic company. M’s response was "I told you it would come to nothing!”

Luckily, I have never been too hung up on money. For me, the really exciting part of process development is the intellectual challenge. Finding ways to develop a process successfully when no-one has done it before. I also learned some valuable lessons about the importance of people and friendship. As a result, I still have regular contact with Henk and others.

But the most important lesson I learned was one of timing. If I had thought up the process ten years earlier I wouldn’t still be paying my mortgage!

To read more of Jimmy Hunter's Chemeng Chronicles, visit the series hub.

Article by Jimmy Hunter BSc CEng CSci

Process engineering consultant, JHunter Process

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