Backyard Chemistry
Background
Manganese dioxide (MnO2) is a jet black powder found in pyrolusite, nature’s most prevalent manganese ore. They are several different crystalline forms of MnO2 and most are not nearly perfectly stoichiometric. Manganese compounds exist in oxidation states from +2 to +7 so with a +4 oxidation state manganese dioxide is already sufficiently electron hungry to serve as an oxidizer in many applications. Its main use by far is in dry-cell batteries, both carbon-zinc and alkaline, where it is reduced by zinc powder to manganese oxide hydroxide. The typical chemical reaction given to describe the processes of such batteries is:
Zn + 2MnO2 + 2H2O --> 2MnO(OH) + Zn(OH)2
This diagram serves as my map when mining old batteries for chemicals. The manganese dioxide is located along the outer walls of the batteries and is simply scraped off. Unfortunately, the manganese dioxide is not nearly pure and is also mixed with graphite and no doubt also has various zinc impurities. It also probably contains a host of lower oxides/hydroxides that need to be removed. This information from the MSDS of Duracell alkaline batteries should give you a good idea of just how rife such impurities are.
Manganese dioxide- 35-40%
Zinc- 10-25%
Potassium hydroxide (35%)- 5-10%
Graphite, natural or synthetic- 1-5%
Cleaning up this mixture of chemicals turns out to be much more complicated (and more intriguing) than your standard textbook filtration and recrystallization processes. The problem lies in the fact that both carbon and manganese dioxide are insoluble in water and all other solvents as far as I know. Therefore, I have developed a way to separated manganese dioxide chemically from the graphite and subsequently regenerate with a series of reactions.
Peter Vinthagen Simpson
Published: 2 Aug 11 12:36 CET
Swedish police have detained a 31-year-old man in Ängelholm in western Sweden who was discovered after he sought advice from authorities on the legality of building a nuclear reactor in a domestic kitchen 
The man began his experiment some six months ago and has reportedly been open about his plans to construct a nuclear reactor in his apartment in the small Swedish coastal town, maintaining a blog of his nuclear adventure.
The man, who explained that his interest in nuclear physics was awakened as a teenager, ordered some radioactive material from overseas and acquired more by taking apart a domestic fire alarm.
Despite the man's frank and full disclosure of his experiment, his activities only came to the attention of the authorities a couple of weeks ago when he contacted the Swedish Radiation Authority (Strålsäkerhetsmyndigheten) to inquire if it was legal to construct a nuclear reactor at home.
The man was told that somebody would be sent to measure the levels of radiation in his flat.
"When they came they had the police with them. I have had a Geiger counter and have not detected a problem with radiation," the 31-year-old told the local Helsingborgs Dagblad (HD).
The man was arrested by the police and taken in for questioning. He admitted to his plans and was later released.
He told the newspaper that had he succeeded in building a nuclear reactor, generating any power would probably have proved beyond him.
"To get it to generate electricity you would need a turbine and a generator and that is very difficult to build yourself," he told HD.
The man is reported to have spent around 6,000 kronor ($950) on his project and after all his equipment was seized in the raid, he has confirmed that in the future he intends to focus on the "theoretical" aspects of nuclear physics.
