So, you are planning a rapid rise to power and wealth without it being so conspicuous that you draw attention from the people that could discover your secret. Should be easy for someone of your genius, right?
Your primary challenge is that whichever "industry" you use for a cover, you absolutely will draw the attention of competitors in that area. The more powerful and established they are, the more they can and will do to investigate, infiltrate, block and hurt you.
Let's use a terrible plan to illustrate some of the considerations for your plan. This is how NOT to do it:
Producing Aluminium from ore is a very wasteful and energy-intensive process. Your machine does it way better, you so "rescue" a bankrupt company and start converting ore into Aluminium and selling it a low prices, undercutting all the competition.
This will fail quickly as there are only a handful of big producers across the world, who all use roughly the same process and get their ore at a number of known suppliers. They know exactly how much ore you should be buying, how much electricity, etc. When they contact your suppliers to find out how much better of a deal you made, they find out you're not buying that much ore, or electricity. They will suspect you're actually selling ill-gotten Aluminium, either stolen or from a country under embargo. This ensures a government investigation and that's it. Game over.
Turning that situation around, here are the things to aim for when selecting an industry:
- It should be hard to trace or measure the input resources for your products
- Government regulation (environmental, licensing) is light or easy to subvert
- There are no too-dominant parties barring your entry.
- It is possible to have multiple smaller operations
- Large profits are the norm, so that yours will not attract undue attention
These goals are impossible to achieve all at once, so you need to go through several phases.
The assumption here is that you have a small capital, either pre-existing or generated through the machine, but no power/influence to exert. You need to stay under everyone's radar and in one place.
The waste processing plant is an excellent start:
- Your machine can masquerade as an new type of incinerator
- You get paid to collect many different kinds of waste of uncertain composition
- You can cheaply dispose of even highly polluted waste, coming up clean on any inspection.
- You can sell higher volumes of "recycled" materials than you collect as that's very hard to trace or prove
As soon as you have some positive business results, you use these to expand by getting a big loan or finding investors. Basically, the way every other business might do it. Don't just build identical plants, go for related businesses. Cleaning up polluted sites, "upgrading" your recycled materials to prime quality. If it looks like it takes a whole big messy factory to achieve those, all the better. Make a lot of noise about how you are cleverly combining processes to conserve energy and protect the environment, etc.
The more related businesses you have and the more they buy and sell from each other, the easier it will be to extract money from them in a kind of reverse laundering of money. Rather than making ill-gotten money appear legitimately on company balances, you are going to make it disappear so you can spend it in different ways.
Note: Buy up a robotics company and a mining company. You will need these later.
At some point, going international will be your best course, as it's much easier to evade scrutiny when no single authority can keep track of all parts of your operation. You will want to either select a country with a weak government (Africa) or mingle in with the biggest flows of trade (China->US/EU).
Let's be brave and go for a corrupt dictatorial (but stable) country in Africa. You will need a sizable amount of money for bribes, but once you get permission to build your factory, there is little risk of "oversight" beyond regular collections of more bribes/protection money.
You will want some combination of power-hungry industrial processes (let's say water desalination) and a "geothermal power plant". You sell water and electricity at cheap rates, building a good reputation with both the populace and the dictator, while secretly making a decent profit since you didn't actually sink all your money into drilling a well underneath your power plant.
Note: pay well for a small security force and have explosives ready near your machine. If the dictator decides to take your plant, blow it up and blame local extremists. Then offer to rebuild it if you are allowed to retain your own security force. The dictator will not risk a revolt by trying again.
While by now you have a reputation, it should hopefully be of a tech-savvy philanthropist trying to clean up the world, rather than of a dictator-loving businessman making obscene profits. You can use this to expand your visible operations, but also start investing some of your hidden money through third parties into unrelated areas, so that you yourself don't become too conspicuous.
Do this until you have a diverse range of income sources so that it's hard for any one opponent to shut you down.
Now it's time to return to the advanced countries and risk the wrath of the big industry players a bit more. You will want to create some dependence on your services/products.
Drinking water may work in the US, given the current drought in the southwest, but not nearly as well as in third world countries. In Europe it wouldn't do anything, but you would have an easier time entering the energy market, as there are more players and the energy industry is not as influential within the government as in the US.
On top of that, you can set up factories in third world countries you are already established in and start shipping high-quality consumer products to the world, "buying" raw materials from your other businesses and using "robots" to minimize labor costs.
All this time you need to delay investigations and hold off hostile actions from competitors. Go on the offensive whenever you feel seriously threatened. Your machine can produce almost any evidence you need (obtain a tiny sample of the real incriminating material, copy a lot of it), but be extremely careful in placing it.
You now are in a position to reveal your great invention, save humanity and create global peace in a new post-scarcity society.
Unfortunately, the governments of the world are absolutely not interested in letting you do any of that, because you threaten the status quo too much. They call on you to surrender your machine to the UN and blueprints as well. Laws are quickly passed forbidding creation, possession and use of your machine. Fortunately, your third world dictator friends may be slower to react as long as you keep the money tap flowing.
All companies you publicly own are raided by the government agencies and competitors and after some close brushes with capture and/or death, you decide
to you need a safer place.
You use the mining equipment and robotics tech acquired earlier to dig out a hidden base in a most unlikely location, a volcano for example. Your machine is now put to use duplicating an army of robots as you prepare to bring salvation to the people by force.
Not long after, your robot army is successful in capturing most capital cities in the world, and the world governments surrender to you one by one (France first). You declare yourself Ruler of the World and use your robot army to force the people to enjoy the benefits of your machine.
Resistance stays constant and costly as you clean up the planet, eliminate hunger, thirst and poverty and stabilize the climate.
You design a great interstellar spaceship using your machine and leave Earth forever, disgusted with the shortsighted, ungrateful creatures that humans are.
Okay, that last bit was not part of the question, I guess...