- High reactivity with heavy metal ions and extremely low solubility of resulting metal sulfides over a wide pH range.
- Can break and precipitate highly chelated and/or complexed heavy metals, typically without pretreatment.
- Removes chromates and dichromates without preliminary reduction of the chromium to its trivalent state.
- Selective metal precipitation allowing for recovery of valuable metals.
- Converts cyanide wastes into less toxic thiocyanate ions. See study on Cyanide Treatment with Polysulfides.
- Dissolved calcium ions form a coagulant aid (Ca(OH)2).
- Better settling and dewatering aspects of the metal sulfides, resulting in a more compact solid sludge. See abstract on Source Reduction Technology Report in Circuit Board Manufacture.
- Remotox can be adapted to enhance any existing treatment system.
- A strong yet relatively inexpensive metal precipitant.
- Its residues are inert and non-toxic.
- Unlike carbamate and carbonate salts, it does not contain carbon disulfide.
- Compared to other sulfides, it provides more stability in acidic medium.
- Remotox has been tested to maintain its effectiveness for a minimum of one year.
- No need to dissolve prior to use as compared to solid material.
- NSF approved for drinking water treatment.
- Not regulated by the DOT (Department of Transportation).
When mixed with water, Remotox decomposes to form bisulfide, aqueous hydrogen sulfide and other sulfur compounds. Most heavy metal ions are precipitated as metal sulfides by these breakdown products. Metal sulfides are much less soluble than metal hydroxides. Metal hydroxides change solubility with changes in pH. Metal sulfides remain insoluble within a wide pH range. See Solubility of Metal Hydroxides and Sulfides as a Function of pH.
In the case of chromium, Remotox reduces hexavalent chromium to trivalent state which then precipitates as chromium hydroxide in a one-step reaction; therefore, no need for sodium bisulfite, metabisulfite, sulfur dioxide or sulfuric acid. See Overall Effectiveness of Water Treatment Process for Cr(III) and Cr(VI).
While effective treatment can be achieved over a wide pH range, best results are typically obtained within water system pH 7-10. See pH Guidelines for Treatment of Soluble Metal Streams. Ensuring adequate contact time and thorough mixing is critical to successful treatment. Dewatering the resulting precipitate can be expedited by employing an anionic flocculant.
For additional information, heavy-metal removal studies, samples or assistance, please contact us at 623-328-5175 or by email at firstname.lastname@example.org.
Remotox® is a calcium polysulfide liquid solution consisting of multiple sulfur anions that strongly bond to heavy metals in water.
Many industrial processes, including printed circuit board manufacturing, electroplating and surface finishing, copper polishing, tanneries, and paint manufacturing, produce wastewater streams containing significant amounts of metals.
Remotox®, a strong and cost-effective Calcium Polysulfide Solution, is commonly used for the removal of a wide range of heavy metals and other inorganic compounds.