Identifying Sulfur Minerals

Sulfur exists in minerals either without oxygen, as in the sulfides, or with oxygen, as in the sulfates. These two types of sulfur compounds require different test.

Test for Sulfur in Sulfides

• Open Tube Test. Sulfides when heated in the open tube gibe off sulfur dioxide gas, which escapes with the current of air form the upper end of the tube. Its presence can be detected by is pungent and irritating odor. A piece of moistened blue litmus paper inserted into the upper end of the tube will turn red on account of the sulfurous acid formed.
• Charcoal Test. The odor of sulfur dioxide may be obtained when a sulfide is roasted on charcoal.
• Fusion with Sodium Carbonate. When a sulfide is fused on charcoal with sodium carbonate, the residue, unless the heating has been to prolonged, will contain sodium sulfide,
• Treatment with Nitric Acid. Some sulfas are completed soluble in nitric acid, yielding sulfuric acid and solution. This can be proved by adding a little barium chloride solution and obtaining the white precipitate of barium sulfate. In other cases the sulfur does not go into solution but separates as a spongy mass, usually black in color, that floats on the solution. Its identity is easily established by removing it and burning it in a flame.

Treatment with Hydrochloric Acid. Some sulfides are soluble in hydrochloric acid yielding hydrogen sulfide gas.

Test for Sulfur in Sulfates
The test for sulfuric acid depends upon whether the sulfate is soluble or insoluble in acids.

• Test for a Soluble Sulfate. If the sulfate is soluble, treat it with hydrochloric acid, and to the resulting solution add a little barium chloride. A heavy white precipitate of barium sulfate will result.
• Test for an Insoluble Sulfate. Powder the mineral, mix with sodium carbonate and charcoal dust and fuse on charcoal in the reducing flame. The charcoal serves to reduce the sulfate to a sulfide, a dark brown stain of silver sulfide will form. It is to be noted that a sulfide would yield the same test (see above), so that it is necessary to make certain that the mineral being tested does not belong to that chemical group.

Azurite – Chessylite, Blue Copper Carbonate Composition & Structure Application for Single-toggle Jaw Crusher Copper Flotation Circuit Relationship Between Feed Size and Roll Diameter of Crusher Roll Crusher Product Characteristics Titanite, Sphene Composition, Crystallization & Structure Sedimentary Uranium Deposits Book and Record Keeping of Prospecting Trips Crusher Operating Cost Flotation GOLD MINING COMPANY CANADA Mining Equipment Europe Sampling a Ore Deposit Vertical Crater Retreat Mining Method Gold Mining Companies Canada