The Study of the Formation of Sodium Chromate from El – Baramiya High Silica Chromite Ore Concentrate Using Dolomite M.E.H. Shalabi 1 , M.G. Khalifa 2 , H.A.M. Abuzeid 3 , F.M.S El–Dars 4 and A.B. Farag 4 Keywords: Chromite Ore Concentrate, Dolomite, El – Baramiya ore – Egypt, Sodium Chromate Recovery. chromium and many others are made possible by the industrial use of chromium. Industry uses chromium in three forms: ferrochrome, chromium chemicals and chromite refractory to make industrial products, which in turn may end up in consumer products (Papp, 2000). While it may be argued that the use of chromite ore in the chemical industry is substantially smaller than that of metallurgical industry, the use of chromium chemicals produced thereafter are quite diverse (Barceloux, 1999). Commercial applications of chromium compounds include tanning (Cr III), corrosion inhibitors, metal plating, glassware – cleaning solutions, wood preservatives (Cr VI) , manufacturing of safety matches and metal finishing (Cr VI) and the production of pigments (Cr III and Cr VI). Abstract The formation of sodium chromate from a mixture of high silica chromite ore concentrate (48.8 %), soda ash and dolomite was investigated. Different amounts of dolomite (0 – 30 %) to an optimal mixture of Na 2 CO 3 : Cr 2 O 3 (mole ratio 2.5: 1) were made and the materials were roasted at 1000 0 C for 40 min. and P o 2 0.21 atm. Results revealed that as the dolomite % increased from 0 to 5, a significant decrease in sodium chromate yield from 42 to 34 % was obtained. Increasing the dolomite percentage from 5 – 30, an optimal chromate yield of 54 % was achieved at 20 %. Furthermore, roasting of optimal mixtures of soda ash, chromite ore and dolomite (mole ratio 2.5: 1 and 20 %) within the temperature range of (900 – 1000 0 C) provided a maximum chromate yield of 77 % at 1000 0 C after 2 hours. The data also revealed that dolomite addition significantly decreased the process energy of activation from 112 kJ / mole for Na 2 CO 3 : Cr 2 O 3 (mole ratio 2.5 : 1) alone to 90.6 kJ / mole for the mixture at a time periods from 40 to 100 minutes. 1. INTRODUCTION Chromium plays an essential but hidden role in human life (Papp, 2000). In many ways, chromium contributes to a clean, efficient and healthy life style as well as in bettering the quality of living both indoors and outdoors. Generally, many consumer products use In the chemical industry, sodium dichromate is used to produce chromic acid, chromic oxide and potassium dichromate (Papp, 2000). The chromate salt is produced by mixing of dried, crushed and ground chromite ore with soda ash and charging the feed into a rotary kiln furnace (Kirk, 1984; Hosdowich, 1965). This requires the maintaining of an oxidizing atmosphere and controlling of temperatures between 1100 – 1150 0 C. The produced chromate is then converted to sodium dichromate from which many other chromium chemicals are prepared (Papp, 2000). A part from this, some technologies were successful in the substitution of natural raw material with chromic waste such chromic mud or the recycling of process wastes containing hydrated chromic oxide for the industrial production of sodium chromate (Walawska 1 Central Metallurgy Research and Development Institute (CMRDI), Cairo, Egypt. 2 El – Tabbin Metallurgical Institute, Cairo , Egypt. 3 National Research Center, Cairo, Egypt. 4 Chemistry Department, Faculty of Science, Helwan University, Helwan, Egypt.