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Sulfur disposal

Submitted by sat on 27 March 2015

Disposal of Sulfur:

Sulfur powder, whilst it is a designated hazardous substance, a flammable solid and a dust inhalation hazard in particular circumstances, has a hazard level considered to be towards the low end of the scale.  Indeed, it is widely sold in garden shops as a soil conditioner to lower the pH of alkaline garden soils.  

The recommended disposal is via a licenced chemical waste disposal company. Details for suitable companies can be found on the School science suppliers list. However, if quantities are small and are not contaminated with other substances, then responsible disposal as a soil conditioner could be considered. Dosage rates advised for soil treatment are commonly in the range of 25 to 100 grams of sulfur per square metre when dug into the top 10 cm. Therefore, if disposing by burial in soil, we recommend that you operate within these limits.

[Please note:  as a general principle we do not endorse the disposal of laboratory chemical wastes either by local burial or in general refuse.  We do so in this case only after careful consideration and risk assessment of the particular substances.]

Disposal of sulfur mixed with iron filings and HCl:

From the given details, we are deducing that the material for disposal is the residue from a series of student investigations about the separation of a mixture of sulfur powder and iron filings, with the dissolving of the iron in hydrochloric acid being one of the steps in this investigation.  If so, then the process would be for the hydrochloric acid to dissolve the metallic iron, and to leave the sulfur as a solid that could be filtered out and thus separated. 

Please respond to us with further details if these assumptions are not correct, or if this response does not fully meet your particular circumstances.

In assessing disposal methods, it is of course not possible for you to have a residue with both iron filings and hydrochloric acid, as these will react chemically until either one or the other is used up.  So we assume that your mixture contains sulfur and either an excess of iron filings or an excess of hydrochloric acid.  We will address both possibilities.  We also assume that the waste quantities are relatively small and are derived from small-scale student activities.

References:

Directions for the use of sulfur as a soil conditioner: https://www.greenlifesoil.com.au/gardening/minerals-fertilizers 

Chem-supply. 2014. Safety Data Sheet Sulfur https://www.chemsupply.com.au/documents/ST0061CH71.pdf

Wilkinson, S. 2015. Science Business Manager, Scientific Services Division, ChemCentre. Western Australia. Personal communication.