Lake Natron

Na is the most abundant extra framework cation. Tsi in the range of 0.74-0.79. Erionite-Na from Durkee, OR, USA Cady Mountains, CA, USA Lake Natron, Tanzania Crooked Creek, OR, USA Phillip Island, Australia Campbell Glacier, Antarctica Mt. Adamson, Antarctica Dunseverik, Northern Ireland Montecchio, Maggiore, Italy and selected samples from Cappadocian region of Turkey passed the balance error and Mg-content test and re-classified as erionite-Na. 

Although the Arrhenius model is useful in explaining many acidic and basic solutions, it has some shortcomings. For example, ammonia (NH3) and sodium carbonate (Na2C03) do not contain a hydroxide group, yet both substances produce hydroxide ions in solution and are well-known bases. Sodium carbonate is the compound that causes the alkalinity of Lake Natron, Tanzania, which is shown in Figure 18.5. Clearly, a model that includes all bases is needed. 

Figure 18.5 Lake Natron in Africa s Great RiftVaiiey is a naturaiiy basic body of water. Water, iaden with dissoived sodium carbonate from surrounding voicanic rocks, drains into the lake but finds no outiet. Evaporation concentrates the mineral leaving a white crust on the surface and strongly alkaline water. 

Fritz, B., M.-P. Zins-Pawlas, and M. Gueddari, 1987, Geochemistry of silica-rich brines from Lake Natron (Tanzania). Sciences Gedlogiques Bulletin 40, 97-110. 

Chrom-kali, n. (rotes) potassium dichromate (gelbes) potassium chromate, -karbid, n. chromium carbide, -lack, m. chrome lake, -leder, n. chrome leather, -leim, m. chrome gelatin chrome glue, -metall, n. chromium metal, -natron, n. (rotss) sodium dichromate (gelbes) sodium chromate, -nickel-stahl, m. chrome-nickel steel. 

Tonerde-hydrat, n. hydrate of alumina (aluminum hydroxide). -kali, n. potassium aluminate. -lack, m. alumina lake. -metaU, n. aluminum, -natron, n. sodium aluminate. -prMparat, n. alumina preparation, tonerderelch, a, rich in alumina, aluminous. Tonerde-galz, n. aluminum salt, -stein, m, alumina brick, -sulfat, n, sulfate of alumina... 

The main source of silica in antiquity, as today, was sand and, very occasionally, crushed rock or pebbles. The most common modifier was soda, which was obtained from natron lakes, as in ancient Egypt, for example, or from vegetable ash. Most lime was derived from limestone, although some lime could also enter the mixture of glass raw materials together with soda... 

H. Abich has investigated the natron lakes of Armenia. The crusts which form about these lakes have from 16 to 23 per cent, of sodium carbonate 16 to 80 per cent, of sodium sulphate 2 to 51 per cent, of sodium chloride and up to about 10 per cent, of water. The mud of Lake Looner (Nizzam, India) dries in summer, and contains a white salt used for washing and soap-making. Wallace s analyses make the soluble portion (74 65 per cent.) ... 

The Owens Lake dusts are derived from lake bed sediments containing abundant alkaline evaporative salts of sodium, chloride, carbonate/ bicarbonate, and sulfate, including, e.g., halite, natron, thermonatrite, mirabilitie, and trona (Saint Amand et al, 1986). In addition, the dusts contain a variety of silicates and other minerals derived from local alluvial material, and possibly some mine waste materials from the Cerro Gordo lead-zinc-silver mining district on the east end of Owens Lake. 

High pH s (10 to 11) are caused by the dissolution of such minerals as nahcolite (NaHCO ) and natron (Na2C03 IOH2O), which form in evaporative alkaline lakes and dissolve according to reactions such as... 

Sodium Carbonate. CNa 03 mo] wt 106.00. C 11.33%, Na 43.39%, O 45.29%, NajCOj. Occurs in nature as the hydrate, thermonatrite, and the decahydrate, natron or natrile. Produced by the ammonia-soda or Solvay process, or from lake brines or sea water by electrolytic processes Faith. Keyes Clark s Industrial Chemicals, F. A. Lowen-heim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 706-715. Toxicity C. Norde et al. Compt. Rend. 257, 791 (1963). Reviews Bailey in Mellor s vol II, suppl II. The Alkali Metals (part 1), 1058-1205 (1961). 

Humans have known about and used sodium carbonate for thousands of years. The ancient Egyptians extracted the compound from a mineral known as natron found in dry lake... 

Specimen Source Spectrum ref. no. Sample medium XRD Composition BM 59235 Crust of colourless prismatic crystals with halite etc. Natron Lakes, Egypt. IR2876 KBr disk 8149F = trona (+ trace quartz). ... 

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