Applications Barium sulphate production

Sulphurj in the unoxidized condition, is tested for by heating the compound with metallic sodium or with sodium carbonate, by which treatment the sulphur is converted into sodium sulphide. If the fused product is placed on a silver coin and moistened, a spot of siVoer sulphide will be produced. The fused mass may also be dissolved in water, neutralized with nitric acid, and a little lead acetate solution added. The formation of a black precipitate of lead sulphide proves the presence of sulphur. These tests are applicable only in case the sulphur is in an unoxidized form. To test for sulphur in either the oxidized or unoxidized form a little of the compound is boiled with strong nitric acid or is heated with sodium peroxide. This treatment converts the sulphur into the form of sulphuric acid or a sulphate, either of which will yield a white precipitate of barium sulphate when tested with barium nitrate in the presence of nitric acid. 

Cement is a binder that sets and hardens by itself or binds other materials together. The most widely known application of cements is in construction a second one is the area of bone cements. Cements used in construction are characterized as hydraulic or nonhydraulic and mostly for the production of mortars and concrete. Hydraulic cements set and harden after combining with water. Most construction cements are hydraulic and based on Portland cement, which consists of calcium silicates (at least 2/3 by weight). Nonhydraulic cements include the use of nonhydraulic materials such as lime and gypsum plasters. Bone cements and bone cement composites refer to compounds that have a polymer matrix with a dispersed phase of particles. For instance, polymethylmethacrylate (PMMA) is reinforced with barium sulphate crystals (for radio-opacity) or with hydroxyapatite... 

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