Abstract:
The invention relates to a cell for metal electrowinning equipped with a device useful for preventing the adverse effects of dendrite growth on the cathodic deposit. The cell comprises a porous conductive screen, positioned between the anode and the cathode, capable of stopping the growth of dendrites and preventing them from reaching the anode surface.
Abstract:
This invention relates to electrodic apparatus suitable for the electrodeposition of nonferrous metals, for example for the electrolytic production of copper and other nonferrous metals from solutions of ions, comprising an electrode and at least one ionpermeable screen intended for protection of the said electrode.
Abstract:
The invention relates to a combined electrolytic system for precipitating different types of metals (copper, zinc, nickel, cadmium, cobalt, silver, gold) and regenerating reagents for the leaching of metal sulphurs from solutions from leaching in a sulphuric-oxidising or hydrochloric-oxidising environment, including a process that permits the combining of the current reduction processes followed by oxidising processes which are complex and potentially dangerous from an environmental point of view, thereby preventing the risky transportation of dangerous substances, loading and unloading operations, storage and manipulation of toxic materials, and reducing the environmentally contaminating waste, producing a commercial-quality cathodic product and a solution that is re-used in the leaching process. The system comprises a membrane cell device (3) that is connected via ducts and valves to one or more oxidising agent tanks (7), to one or more anodic solution tanks (6) and to one or more cathodic solution tanks (2), wherein said membrane device (3) is formed by one or more cathodic compartments (4) and by one or more anode compartments (5), wherein each of the cathodic compartment(s) (4) is/are separated from each of the anode compartment(s) (5) by a membrane for selective and uni-directional ion exchange.
Abstract:
This invention relates to a method for the preparation of lithium carbonate from lithium chloride containing brines. The method can include a silica removal step, capturing lithium chloride, recovering lithium chloride, supplying lithium chloride to an electrochemical cell and producing lithium hydroxide, contacting the lithium hydroxide with carbon dioxide to produce lithium carbonate.
Abstract:
A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a microstructure exhibiting substantially uniform pore size distribution as a result of using PMMA pore forming materials or a bi-modal particle size distribution of the porous support layer materials. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.
Abstract:
The disclosed subject matter includes a new type of chemical reactor, described as hydrogen or oxygen electrochemical pumping catalytic membrane reactor. This new type of reactor is suitable for increasing the selectivity and the conversion rate of dehydrogenation, hydrogenation, deoxidation and oxidation reactions and namely in the direct amination reaction of hydrocarbons. This reactor can be used for the production of several chemical compounds, such as the direct amination of hydrocarbons and in particular for the synthesis of aniline from benzene. The disclosed subject matter includes a device and process wherein hydrogen is removed by electrochemical pumping of the hydrogen formed or by oxygen pumping so, as hydrogen is formed, it is oxidized. This new reactor exhibits benzene to aniline conversion higher than 40%.
Abstract:
The electrochemical cell consists of hollow tube and centralized copper rod. The tubes have first and second ends. The first end cap is used to close the first open end. The anolyte inlet is extended through the first end cap in anolyte compartment and catholyte inlet is extended through the first end cap in catholyte compartment. The anolyte and catholyte compartments are separated by ion exchange membrane fixed over inner hollow tube having holes on the surface. A first Teflon gasket has provision for inlet of anolyte and catholyte tube is secured between first tubes end and first end cap. The copper rod is placed at the center of the tubes acts as cathode. The circular ring works as scrapper to take out deposited copper is provided. A second end cap is used to close the second open. A second Teflon gasket is secured between second tubes end and second end cap. The second end cap has provision for anolyte outlet and comprises a conical dome to collect the deposited copper and transport it along with catholyte. The anolyte trappers and catholyte trappers are connected through the tubes to anolyte and catholyte half cells. The anolyte and catholyte are re-circulated through peristaltic pumps, one on each side.
Abstract:
A bipolar electrolytic cell particularly useful for electrochemical processes carried out with periodic reversal of polarity is provided. The cell is equipped with a series of concentric electrode pairs, the innermost pair and the outermost pair being connected to the poles of a DC generator and the intermediate pairs acting as bipolar electrodes. The different pairs of electrodes are arranged and connected in such a way that, at each stage of the process, the overall cathodic area is equal to the anodic area.
Abstract:
A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.
Abstract:
The invention relates to a synthetic diaphragm for chlor-alkali cells with improved energy consumption and gas separation characteristics. The diaphragm comprises a network of polymer fibers bound to a hydrophilic ceramic material containing zirconium chemically bound to hydroxyl groups. The ceramic material is obtained starting from ZrO2 by a process of hydration under vacuum which can be carried out directly in the cell by means of suitable equipment.