Eco-tec Limited

Pulp and Paper Research Institute of Canada

Standard Lithium Ltd.

Craig J Brown

Michael A Sheedy

Michael Paleologou

Rokhsareh Thompson

Richard M Berry

Antonio G Mazza

Michael J Dejak

A process for recovery of lithium ions from a lithium-bearing brine includes contacting the lithium-bearing brine with a lithium ion sieve (where that LIS includes an oxide of titanium or niobium) in a first stirred reactor to form a lithium ion complex with the lithium ion sieve, and decomplexing the lithium ion from the lithium ion sieve in a second stirred reactor to form the lithium ion sieve and an acidic lithium salt eluate.

Process for recovery of lithium from brine

The filter contaminant loading capacity of a depth granular media filter is increased by imposing a so-called 'back-slip' on the filter bed. At intervals between normal backwashing, a volume of liquid is passed upwardly through the media bed under flow conditions selected to displace at least some of the contaminants upwardly in the bed while essentially removing none of the contaminants from the filter vessel. Preferably, the filter bed comprises at least two media types of different but uniform particle sizes and densities, the media types each forming a distinct layer in which the effective particle size of the media in each successive layer decreases in a downward direction in the vessel.

Method and apparatus for increasing filter contaminant loading capacity

A process using an amphoteric ion-exchange resin, also known as a 'snake-cage polyelectrolyte' resin separates kraft white liquor into sulphide-rich and caustic-rich components. The sulphide-rich component can be used in the initial stage of pulping, pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.

Process for the separation of sulphides from pulping liquors using

Sodium chloride is removed from pulping chemicals used in a Kraft pulping process by the use of a snake-cage polyelectrolyte ion exchange resin, coupled with removal of sulfide prior to treatment, or treatment of chemicals which are already low in sulfide. In one aspect of the invention, dust is collected from exhaust gases produced in the black liquor recovery cycle and is dissolved in water to produce a solution containing sodium chloride and sodium sulfate. The solution is filtered to yield a solid product and a filtrate solution. The filtrate solution is fed to an ion exchange unit which removes chloride and produces a purified sodium sulfate product. The sodium chloride is removed from the ion exchange resin by water elution, and useful recovered chemicals are recycled to the recovery cycle of the Kraft process. In one embodiment, only a portion of the dust is dissolved so that the solid product produced by filtering is primarily sodium sulfate, and that sodium sulfate is recycled to the recovery cycle of the Kraft process. In another aspect of the invention, white liquor from the pulping process is treated directly after oxidizing sulfide to sulfate. After removal of sodium chloride in the ion exchange unit, the treated white liquor can be used as a source of sodium hydroxide for oxygen delignification, and the effluent from the oxygen delignification stage can be returned to the process.

Method and apparatus for removing sodium chloride from pulping chemicals

A process employing a fixed-resin bed Acid Retardation Unit (ARU) to separate spent acid from chlorine dioxide generators into a de-acidified sodium sulfate component and a purified sulfuric acid component. The de-acidified sodium sulfate produced is returned to the chemical recovery cycle of the kraft mill in place of acidic chlorine dioxide generator effluent thereby avoiding the destruction of alkalinity in pulp mill liquors. In addition, sulfuric acid is purified providing an opportunity for reuse in various mill applications, and/or concentrated and recycled to the generator. Alternatively, to avoid high evaporation costs, the purified acid can be used to regenerate a cation-exchange unit (CEU) used in the conversion of sodium chlorate to a sodium chlorate/chloric acid mixture which is fed to the generator in place of sodium chlorate and sulfuric acid. Using this approach, the sulfuric acid requirement of chlorine dioxide generators and, in turn, the amount of acidic generator effluent can be reduced. The process is applicable to both atmospheric and subatmospheric chlorine dioxide generators. In the latter case, the concentration of the purified sulfuric acid from the ARU or any other acid separation system can be increased by using a portion of it to dissolve the sodium sesquisulfate by-product from such generators.

Fixed-resin bed technologies for the treatment of the chlorine dioxide

Acids contaminated with multi-valent metal salts are purified by a process which involves treatment in an acid sorption unit (ASU) and a nanofiltration unit (NFU). The feed solution can first be delivered to the ASU, which produces two solutions, one high in acid concentration and the other high in metal salt concentration. The high acid concentration solution can be treated in the NFU to produce an acid end product and a reject metal salt solution which can be recirculated to the feed of the NFU. Alternatively, the high metal salt solution can be treated in the NFU, and its permeate recirculated to the ASU as eluate. In an alternative configuration, the feed is delivered first to the NFU. In all cases, the membrane reject solution from the NFU is recirculated to increase the metal salt concentration. A second NFU can be used to process the solution from the ASU which contains a high metal salt concentration.

Process and apparatus for purification of contaminated acids

Volatile acids containing metal salt impurities, such as metal pickling solutions-are regenerated by a process in which the acid is subjected to sulfuric acid distillation. Resulting volatile acid vapor is condensed and recycled to the pickle tank, while the residual acid mixture is treated in an acid sorption unit, preferably of the acid retardation type. Acid sorbed in the acid sorption unit is periodically eluted with water and recycled, while metal impurities are rejected in a deacidified by-product solution.

Process for regeneration of volatile acids

An electroplating cell having soluble and insoluble anodes is provided with a primary power supply having a positive terminal connected to the soluble anodes and a negative terminal connected to a cathode including workpieces to be plated. An auxiliary power supply has a positive terminal connected to the insoluble anodes and a negative terminal connected to the negative terminal of the primary power supply so that the voltage applied to the insoluble anode is equal to the sum of the voltages applied by the two power supplies.

Process for electroplating metals

A process and apparatus for electroplating metals in which the metal salt concentration within the electroplating bath is reduced by providing an insoluble anode assembly in the bath. The insoluble anode assembly includes an enclosure which defines a compartment around an insoluble anode and which is formed at least in part by an anion exchange membrane. The primary reaction at the insoluble anode during electroplating is electrolysis of water to produce predominantly oxygen and hydrogen ions. The flow of current through the insoluble anode assembly causes anions in the plating solution to travel through the anion membrane into the compartment, resulting in an increase in acid concentration within the compartment. Accumulated acid is periodically flushed from the compartment.

Process and apparatus for control of electroplating bath composition

A process for electroplating metals in an electroplating cell in which the anode current efficiency of the cell is greater than the cathode current efficiency. Buildup of excess metal in the cell is counteracted by circulating the plating solution through an electrowinning cell and plating out the excess metal onto cathodes in the electrowinning cell. The amount of current flowing through the electrowinning cell is controlled so that the amount of the said current which results in the deposition of metal is at least substantially equal to the amount of current flowing through the electroplating cell which results in the evolution of hydrogen gas.

An apparatus for electroplating metals in an electroplating bath having an anode and a cathode. The cathode is formed by a workpiece to be plated and the anode includes soluble material in the form of the metal to be plated and insoluble material in a proportion selected so that the anode efficiency equals the cathode efficiency. This avoids metal salt build-up in the bath. Metal salt solution carried out of the bath with the workpiece is recovered and recycled to the bath, avoiding loss of metal to the system and waste disposal problems.

Apparatus for electroplating metals

A process for electroplating metals in an electroplating bath having an anode and a cathode. The cathode is formed by a workpiece to be plated and the anode includes soluble material in the form of the metal to be plated and insoluble material in a proportion selected so that the anode efficiency equals the cathode efficiency. This avoids metal salt build-up in the bath. Metal salt solution carried out of the bath with the workpiece is recovered and recycled to the bath, avoiding loss of metal to the system and waste disposal problems.

An apparatus and process for treating a fluid by passing the fluid through a bed of particulate material such as an ion exchange resin capable of taking up from the fluid a component to be removed therefrom. Substantially uniform fluid flow distribution across the cross-sectional area of the bed is achieved by employing resins of fine particle size which are maintained in an overpacked condition.

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Pickering, Canada

Craig J Brown