MMM Classics Year 7: MMM #s 61-70

The principal avenues for introducing color on theMoon as in Space Settlements built mostly of lunar materialsare these: 1) luxuriant green vegetation and colored foliage andflowers; 2) naturally colored cotton and natural organic fabricdyes that do not stress water recycling systems; 3) vitreousstains for coloring glass and glazing ceramics; 4) inorganic“paints” that do not tie up precious carbon or nitrogen; finally5) colored “neon” lighting using noble gases scavenged fromregolith-moving activities.In this article we will deal with 3) and 4) above:inorganic chemical agents for decorating interior surfaces andto support a vigorous arts and crafts enterprise. The criticalimportance for keeping up settler spirits so that the populacecan sustain overall high productivity, will demand that theprocessing of such agents be totally integrated, on a highpriority basis, into the overall lunar industrialization strategy.The bottom line is that those planning beneficiationsuites and cascades needed to “stock up” the lunar industrial“pantry” with available “processed” elements, will have to payas much attention to the production of coloring agents as to thatof elements needed for metal alloys and glass and ceramicadditives. Happily our chemical engineers will find that manyelements desirable for alloying can also support colorization.Stained glass and vitreous ceramic glazesStaining glass and applying colored glassy glazes toceramic ware both have venerable, millennia-long histories.New coloring agents have been explored and experimentedwith to expand the choice of hues, tints, shades, brightness,opacity, transparency, and ease of workability.Lunar pioneers will find many of the choices we nowtake for granted closed to them - those that involve chemicalelements that we won’t be able to produce economically on theMoon for a long time to come or must instead be expensivelyupported out of Earth’s gravity well. Those lunar-supportablechoices that remain will yield a distinctive lunar palette. Theorder in which these agents become available will clearly mark“periods” in lunar decor.[Elements not easily produced on the Moon shown in italics]REDSFamiliar agents that can’t be produced on the Moon:lead chromate, cadmium sulfide, cadmium sulfo-selenide, andmanganese copper. Lunar chemical engineers will be able toproduce the chrome, the sulfur, and the manganese, but will nottoo soon nor too easily come up with the lead, cadmium,selenium or copper.Fortunately, aluminum oxide mixed 4:1 with ferricoxide Fe2O3 produces an attractive red. While lunar iron ismostly ferrous, yielding FeO, the ferric oxide can be preparedby controlled rusting of native iron fines from the regolith. Aspinel, FeO. Fe2O3, produces a darker red. A tomato red canbe prepared from Uranium oxide which can likely be foundwith known Thorium deposits.PINKSLead chromate and chrome tin pinks are out - little orno lead or tin. Chromium-zirconium is a possible substitute. Amanganese-alumina pink and a chromium-alumina pinkish redare other choices. Eventually, cobalt-magnesium combinationsmight produce a pink to lilac range .ORANGESUnsupportable lunar options are Uranium-cadmiumand chromium-iron-zinc. Glazers may have to blend availablereds and yellows.YELLOWSThe list of closed options is long: lead chromate, leadnitrate, zinc oxide, antimony oxide, red lead, potassiumantimoniate, vanadium-tin. Instead colorizers will have to playwith vanadium-zirconium and titanium-iron oxide preparations.BROWNSUnavailable will be the orange brown of copper-basedCuO.Al2O3 and the reddish brown of zinc-based ZnO.Fe2O3.But in stock should be the reddish brown of iron chromateFeO.Cr2O3, the Indian red-brown of magnesium-iron oxideMgO.Fe2O3, and the red-brown manganese titanate MnTiO4.GREENSOut are chromium-beryllium, lead chromate, copper,and copper-vanadium preparations now in use. A blend ofyellowing vanadium and bluing zircon in the presence ofsodium fluoride (if fluorine can be produced, a difficult buthigh industrial priority) is an option. Praseodymium (fromKREEP deposits) phosphate with a calcium fluoride additive isanother. The deep emerald green of chromium oxide may bethe standby. This could be blended with available yellows andblues to produce neighboring tints.BLUESMy favorite color. If we can’t do blue, I ain’t goin’!Many blue ceramic stains use zinc oxide, barium carbonate, tinoxide, and copper phosphates. Fortunately cobalt aluminateyields a matte blue, and cobalt silicates and oxides producemazarine blue, royal blue, flow blue, and willow blue. Atitania-alumina blue, TiO2.Al2O3, with a corundum structure isa possibility but it is difficult to prepare by synthesis asopposed to starting with Ti-rich bauxite. Other choices includea vanadium-zirconia blue and a silica-zirconia-vanadia-sodiumfluoride system of blues, turquoises and greens. I can go!WHITESCommonly used tin and antimony oxides will likelybe unavailable. Instead, titanium dioxide, zirconium dioxide,and zirconium silicate seem the way to go.BLACKSBlacks have always been the most difficult stains toproduce as there are few truly black inorganic agents. Insteadwe are left to blend semi-blacks with noticeable green, blue, orbrown casts to them in hopes of neutralizing those tints andbeing left with apparent true black. Given the narrowed list ofpreparations available on the Moon for blending, coming upwith a satisfying black will be especially difficult.COMPLICATIONSMaking everything harder is the fact that the choice offlux affects the color outcome. Lead fluxes will be unavailable.While there has been considerable success in preparing leadfreeglazes and fluxes on Earth, many of the substitutepreparations rely on other elements hard to come by on theMoon such as zinc. Glazes based on feldspar (aluminosilicatesMoon Miners’ Manifesto Classics - Year 7 - Republished January 2006 - Page 23