This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

The present invention discloses a method of using a waste silicon slurry. The method includes the steps of: (A) obtaining a waste silicon slurry containing a cutting oil and a metal; (B) treating the waste silicon slurry with a first reagent for reacting with the cutting oil; (C) treating the waste silicon slurry with a second reagent for reacting with the metal; (D) separating products resulting from step (B) and step (C) to obtain a solid portion; and (E) treating the solid portion with a third reagent to obtain products, including silicates and hydrogen gas.

An oil recovery process which utilizes chemical precipitation and complexation reactions to remove dissolved organics and silica from waste water streams. The process produces brine suitable for deep well injection and solids suitable for Class II landfill. The treatment process can be used in combination with a concentrator and in addition to producing brine suitable for deep well injection and solids suitable for Class II landfill, the concentrator also produces a clean water stream for reuse. By including a crystallizer for the brine processing the system has zero liquid discharge.

The water treatment system includes: an aluminate ion addition part for adding an aluminate ion additive to water to be treated containing at least salt content and silica; a first precipitation part provided on the downstream side of the aluminate ion addition part; a first pH adjustment part provided on the downstream side of the first precipitation part; a first solid/liquid separation part for separating the solid content in the water to be treated; a second pH adjustment part for adjusting the pH of the water to be treated from the first solid/liquid separation part to a second pH level; and a first separation membrane (desalination treatment) apparatus provided on the downstream side of the second pH adjustment part so as to separate the water to be treated into first permeated water and first non-permeated water by removing the salt content in the water to be treated.

A wastewater treatment process in the production of nickel cobalt hydroxide includes the following steps: S1. subjecting a laterite nickel ore acid-leaching solution successively to iron-aluminum removal and nickel-cobalt precipitation to obtain wastewater; S2. subjecting the wastewater successively to chromium ions, manganese ions, and silicon ion removal treatments to obtain a suspension; and S3. reusing portion of the suspension and continuing iron-aluminum removal; subjecting the remaining suspension successively to homogenizing, alkali adjusting, standing still, CCD counter-current washing, and solid-liquid separation to obtain a supernatant and a residue phase, collecting the residue phase, and discharging the supernatant after neutralization. This method used to treat the laterite nickel ore wastewater can meet the discharge standard, with high safety.

A wastewater treatment process in the production of nickel cobalt hydroxide includes the following steps: S1. subjecting a laterite nickel ore acid-leaching solution successively to iron-aluminum removal and nickel-cobalt precipitation to obtain wastewater; S2. subjecting the wastewater successively to chromium ions, manganese ions, and silicon ion removal treatments to obtain a suspension; and S3. reusing portion of the suspension and continuing iron-aluminum removal; subjecting the remaining suspension successively to homogenizing, alkali adjusting, standing still, CCD counter-current washing, and solid-liquid separation to obtain a supernatant and a residue phase, collecting the residue phase, and discharging the supernatant after neutralization. This method used to treat the laterite nickel ore wastewater can meet the discharge standard, with high safety.

A wastewater treatment process in the production of nickel cobalt hydroxide includes the following steps: S1. subjecting a laterite nickel ore acid-leaching solution successively to iron-aluminum removal and nickel-cobalt precipitation to obtain wastewater; S2. subjecting the wastewater successively to chromium ions, manganese ions, and silicon ion removal treatments to obtain a suspension; and S3. reusing portion of the suspension and continuing iron-aluminum removal; subjecting the remaining suspension successively to homogenizing, alkali adjusting, standing still, CCD counter-current washing, and solid-liquid separation to obtain a supernatant and a residue phase, collecting the residue phase, and discharging the supernatant after neutralization. This method used to treat the laterite nickel ore wastewater can meet the discharge standard, with high safety.

A wastewater treatment process in the production of nickel cobalt hydroxide includes the following steps: S1. subjecting a laterite nickel ore acid-leaching solution successively to iron-aluminum removal and nickel-cobalt precipitation to obtain wastewater; S2. subjecting the wastewater successively to chromium ions, manganese ions, and silicon ion removal treatments to obtain a suspension; and S3. reusing portion of the suspension and continuing iron-aluminum removal; subjecting the remaining suspension successively to homogenizing, alkali adjusting, standing still, CCD counter-current washing, and solid-liquid separation to obtain a supernatant and a residue phase, collecting the residue phase, and discharging the supernatant after neutralization. This method used to treat the laterite nickel ore wastewater can meet the discharge standard, with high safety.

A process for simultaneously removing silica and reducing total hardness of a natural or waste water containing silica and scale-forming ions is described. The process comprises adding (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to said water while maintaining the pH of said stream at pH>8 to produce a layered double hydroxide in situ, wherein the layered double hydroxide contains the scale-forming ions in a lattice of the layered double hydroxide and silica is incorporated in the lattice of the layered double hydroxide as an interlayer anion and/or bound by the layered double hydroxide via one or more binding modes.

A process for simultaneously removing silica and reducing total hardness of a natural or waste water containing silica and scale-forming ions is described. The process comprises adding (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to said water while maintaining the pH of said stream at pH>8 to produce a layered double hydroxide in situ, wherein the layered double hydroxide contains the scale-forming ions in a lattice of the layered double hydroxide and silica is incorporated in the lattice of the layered double hydroxide as an interlayer anion and/or bound by the layered double hydroxide via one or more binding modes.