KemMet™ Metal Precipitant for
Mine Streams
EFFECTIVE IN PRECIPITATING LOW CONCENTRATIONS OF METAL IONS
FROM MINE WASTE
KemMet™ 1140 precipitant is an aqueous solution of sodium dimethyldithiocarbamate,
(CH3) NCS2Na recommended for mine waste containing up to 500 ppm of total metal
ions. It should also be considered as an alternative or adjunct to other, more conventional
techniques for the precipitation of much higher levels of dissolved metal ions.
KemMet 1140 technology is extremely effective in
precipitating various free, complexed and chelated
metals, such as copper, nickel, cadium, chromium+3,
gold, silver, iron, magnesium, mercury, zinc and lead.
The insoluble metal complexes may appear as colloidal
precipitate or as sizable flocculant, depending on the
particular waste stream. The precipitation reaction is
as follows:
2[(CH3)2NCS2 NA+] +M+2 2Na+— 2[(CH3)2NCS2]
M+2 + 2Na+
APPLICATION
The approximate treatment of KemMet 1140 metal
precipitant for a particular metal ion can be calculated
by multiplying the metal ion valence by 358 and then
dividing by the atomic weight of the metal. However,
most waste streams contain multiple metals. It may be
necessary to treat at a level higher than the calculated
stoichiometric equivalent for the target metals. The
table shown to the right presents the recommended
dosage based on the stoichiometric equivalent for
some selected metals. To determine dosage, multiply
the metal concentration in ppm by the value indicated
for the selected metal.stabilize calcium phosphate and
provide iron transport.
SOLUBLE PREFERENTIAL AND TREATMENT RATES
KemMet 1140 Heavy Metal Precipitant Solubility Series
Cu-<Ni<Co<Pb<Zn<Mn<Fe
KemMet 1140 precipitant functions over a broad
pH range. After pH adjustment of the waste stream,
KemMet 1140 precipitant can be added either
continuously or on a batch basis as required. The
efficiency of KemMet 1140 heavy metal precipitant
is increased when the application point allows the
maximum contact and agitation time. Contact and
agitation time will vary depending upon particular the
metal ions and other waste contaminants in the stream.
KemMet 1140 Precipitant Dosage Multiplier (Ppm)
METAL
DOSAGE
METAL
DOSAGE
Ag+
4
Co+2
13
Au+
2
Mg+2
33
Au+3
6
Ni+2
13
Cd+2
7
Cr+3
23
Fe+2
14
Cu+
6
Fe+3
21
Cu+2
12
Hg+
2
Pb+2
4
Hg+2
4
Zn+2
12
POLYMER CO-ADDITIVES
The precipitation and dewatering of KemMet 1140
metal sludge can be generally enhanced through
the addition of polymers and coagulants. In most
applications, Kemira’s anionic polyacrylamide,
Superfloc® A-130 or Superfloc A-130HMW should
be evaluated. This addition will usually improve
settling rates, enhance dewatering characteristics
and improve the clarity of effluent stream. In cases
where an anionic polymer alone does not yield desired
results, our cationic coagulant, Superfloc C-577,
should be evaluated.
PROGRAM COMPARISONS
KemMet 1140 precipitant significant advantages over other technologies for removing metal ions:
KemMet 1140 precipitant vs. sodium hydrosulfite
• Superior removal of metal ions
• Reduces acid and caustic demand
• Significantly reduces sludge volume
• Eliminates toxic dust
• Eliminates the need for temperature control
• Reduces pH sensitivity
• Reduces sludge disposal costs due to superior stability
KemMet 1140 precipitant vs. trithiocarbonate
• Superior metal precipitate stability
• Reduces treatment costs
• Superior flocculation tendency
• Reduces sludge disposal costs due to superior stability
• Reduces pH sensitivity
• Does not produce H2S by–product
KemMet 1140 precipitant vs. sodium borohydride
• Superior metal precipitate stability
• Reduces treatment costs
• Superior flocculation tendencies
• Reduces sludge disposal costs due to superior stability
• Reduces pH sensitivity
• Does not produce borate by–product
KemMet 1140 precipitant vs. ferrous sulfate
• Superior removal of metal ions
• Eliminates additional sulfate requirements
• Reduces acid and caustic demand
• Significantly reduces sludge volume
• Reduces pH sensitivity
ASK US ABOUT OUR
CASE STUDIES OF
PROVEN SOLUTIONS
FOR MINE WATER
METALS REMOVAL
Research & Development
Experienced Research and Development staff, along
with our Applications Experts and Technical Sales
Representatives are available to supply more than just
chemicals for metals removal. They can assist in the
selection of the optimum dose of KemMet 1140 precipitant
and polymer additives for your application.
Kemira’s experience developing effective mine water
metals removal programs with the proper application of
KemMet 1140 is supported by several case studies which
are available upon request.
KemMet is a trademark of Kemira Oyj or its subsidiaries.
Kemira Oyj
Porkkalankatu 3
P.O. Box 330
FI-00101 Helsinki
Finland
www.kemira.com
Europe, Middle East and Africa
Tel. +358 10 8611
Americas
North America
Tel. +1 770 436 1542
Asia - Pacific
Tel. + 86 21 6037 5999
South America
Tel. +55 11 2189 4900
V. 4.4
Kemira makes this information available as an accommodation to its customers and it is intended to be solely a guide in customers’ evaluation of the products. You must test our
products to determine if they are suitable for your intended uses and applications, as well as from the health, safety and environmental standpoint. You must also instruct your
employees, agents, contractors, customers or any third party which may be exposed to the products about all applicable precautions. All information and technical assistance is
given without warranty or guarantee and is subject to change without notice. You assume full liability and responsibility for compliance with all information and precautions, and
with all laws, statutes, ordinances and regulations of any governmental authority applicable to the processing, transportation, delivery, unloading, discharge, storage, handling,
sale and use of each product. Nothing herein shall be construed as a recommendation to use any product in conflict with patents covering any material or its use.