Treatment of thick fine tailings including chemical immobilization, polymer flocculation and dewatering

A process for treating thick fine tailings that includes contaminants of concern (CoCs) and suspended solids, the process comprising:

• subjecting the thick fine tailings to chemical immobilization and polymeric flocculation to chemically immobilize the CoCs and polymerically flocculate the suspended solids, to produce treated thick fine tailings;
• dewatering the treated thick fine tailings to produce:
• an aqueous component depleted in the CoCs and the suspended solids;
• and
• a solids-enriched component comprising the chemically immobilized CoCs and the flocculated solids;
• and
• forming a permanent aquatic storage structure (PASS) for retaining the solids-enriched component, the PASS comprising:
• a water cap;
• and
• a consolidating solids-rich lower stratum below the water cap and inhibiting migration of the CoCs into the water cap.

A process for treating fine tailings that includes contaminants of concern (CoCs) that are water mobile and suspended solids, the process comprising:

• adding an immobilization chemical to the fine tailings to react with the CoCs and enable immobilization of the same;
• adding a flocculant to flocculate the suspended solids;
• producing a treated tailings material;
• dewatering the treated tailings material to produce:
• a water component;
• and
• a solids-enriched component comprising:
• the CoCs rendered water immobile;
• and
• flocculated solids;
• and
• forming a permanent aquatic storage structure (PASS) for retaining the solids-enriched component, the PASS comprising:
• a water cap;
• and
• a consolidating solids-rich lower stratum below the water cap and inhibiting migration of the CoCs into the water cap.

A process for treating mature fine tailings (MFT) derived from oil sands extraction and including constituents of concern (CoCs) comprising bitumen, naphthenic acid, arsenic and selenium, the process comprising:

• retrieving MFT from a tailings pond;
• providing an in-line flow of the MFT;
• adding in-line an aqueous immobilization solution into the in-line flow of MFT, the aqueous immobilization solution comprising an immobilization chemical comprising ferric sulphate, and in-line mixing thereof with the MFT, thereby producing a pre-treated tailings flow comprising:
• immobilized bitumen-clay complexes comprising ferric cations forming cation bridges between negatively charged bitumen droplets and negatively charged clay particles;
• insolubilized naphthenic acid;
• insolubilized arsenic;
• and
• insolubilized selenium;
• adding in-line an aqueous flocculant solution into the pre-treated tailings flow to form a flocculating material;
• in-line conditioning of the flocculating material to produce a flocculated material in a water release zone;
• discharging the flocculated material into a pit and allowing release water to separate from a solids-enriched material;
• forming a permanent aquatic storage structure (PASS) in the pit for retaining the solids-enriched material and a water cap, the solids-enriched material:
• forming a consolidating solids-rich lower stratum below the water cap;
• and
• retaining the immobilized bitumen-clay complexes, the insolubilized naphthenic acid, the insolubilized arsenic and the insolubilized selenium to inhibit migration of the CoCs into the water cap.

A process for treating thick fine tailings that includes contaminants of concern (CoCs) and suspended solids, the process comprising:

• subjecting the thick fine tailings to polymeric flocculation to flocculate the suspended solids and produce a flocculated tailings material;
• subjecting the flocculated tailings material to chemical immobilization to immobilize the CoCs;
• dewatering the flocculated tailings material to produce:
• an aqueous component depleted in the CoCs and the suspended solids;
• and
• a solids-enriched component comprising the chemically immobilized CoCs and the flocculated solids;
• and
• forming a permanent aquatic storage structure (PASS) for retaining the solids-enriched component, the PASS comprising:
• a water cap;
• and
• a consolidating solids-rich lower stratum below the water cap and inhibiting migration of the CoCs into the water cap.

A process for treating thick fine tailings that includes contaminants of concern (CoCs) and suspended solids, the process comprising:

• simultaneously adding an immobilization chemical and a polymer flocculent into the thick fine tailings, in order to chemically immobilize the CoCs and polymerically flocculate the suspended solids;
• dewatering the thick fine tailings to which the immobilization chemical and the polymer flocculant were added to produce:
• an aqueous component depleted in the CoCs and the suspended solids;
• and
• a solids-enriched component comprising the chemically immobilized CoCs and the flocculated solids;
• and
• forming a permanent aquatic storage structure (PASS) for retaining the solids-enriched component, the PASS comprising:
• a water cap;
• and
• a consolidating solids-rich lower stratum below the water cap and inhibiting migration of the CoCs into the water cap.

A process for treating thick fine tailings that includes contaminants of concern (CoCs) and suspended solids, the process comprising:

• adding a polymeric compound to the thick fine tailings, the polymeric compound comprising multivalent cation groups and organic polymeric groups, the multivalent cation groups effecting chemical immobilization of the CoCs and the organic polymeric groups effecting the polymeric flocculation of the suspended solids;
• dewatering the thick fine tailings to which the polymeric compound was added to produce:
• an aqueous component depleted in the CoCs and the suspended solids;
• and
• a solids-enriched component comprising the chemically immobilized CoCs and the flocculated solids;
• and
• forming a permanent aquatic storage structure (PASS) for retaining the solids-enriched component, the PASS comprising:
• a water cap;
• and
• a consolidating solids-rich lower stratum below the water cap and inhibiting migration of the CoCs into the water cap.