There is provided a hyper-branched polymer represented by the following formula (1) and having a weight-average molecular weight in a range of 1,000 to 1,000,000. In the formula (1), A.sup.1 is a group containing an aromatic ring, A.sup.2 is a group containing an amide group, A.sup.3 is a group containing sulfur, R.sup.0 is hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, ml is in a range of 0.5 to 11, and n1 is in a range of 5 to 100. ##STR00001##

This invention relates to methods for the recovery of precious metals such as gold, silver, platinum, palladium and rare earths from precious metal-bearing materials. In particular, a method of purifying precious metal from a precious metal-bearing material comprising the steps a) forming an aqueous acidic oxidant mixture from hydrogen peroxide an acid and a source of bromide ion, said acidic oxidant mixture having a pH in the range 0 to 6; b) contacting the acidic oxidant mixture with the precious metal bearing-material to oxidise the metal and form a metal bromide salt solution containing the metal bromide MBr.sub.n and/or [MBr.sub.n+1].sup.− where n is the valency of the oxidised metal ion M.sup.n+; and c) controlling the metal bromide salt solution to a value in the range 3-7 by providing alkali metal ions A.sup.+ in the solution to form an alkali metal/metal bromide solution containing the salt AMBr.sub.n+1 in solution.

Methods for producing silver nanostructures with improved dimensional control, yield, purity, monodispersed, and scale of synthesis.

Discloses a hydrometallurgical process and system for the recovery of precious metals; specifically palladium, rhodium, and platinum metals, at high purity and with limited waste and environmental fouling.

Solutions and methods for leaching coinage metals. For example, Solutions and methods for leaching copper and/or silver from a substance comprising copper and/or silver (such as a coinage metal-concentrate, or electronic waste) using a water-miscible stabilizer in combination with leaching reagents to form leach solutions.

Compositions comprising extracts of kale and a number of other plants in synergistic mixtures are disclosed. A method of forming a metal nanoparticle and a nanoparticle formed using the method are disclosed.

The present disclosure is directed to a gold recovery process in which activated carbon or another carbon-based material is used to accelerate thiosulfate leaching of gold from a gold-bearing material.

Disclosed herein is a micro particle with a diameter of 10-100 microns, wherein the micro particle is coated with silver nanoparticles; and wherein the nanoparticles are coated with a polysaccharide; and wherein the polysaccharide coating is digestible by bacteria. Also, disclosed is a method of making silver nanoparticles using an ascorbic acid derivative or an alpha-hydroxyl carboxylic acid derivative as a reducing agent. The silver nanoparticles may be coated onto micro particles, embedded in hydrogel particles or coated with polysaccharide. The silver nanoparticles may be used in a wound dressing, a bandage, a fungal treatment product, a deodorant, a floss product, a toothpick, a dietary supplement, dental X-ray, a mouthwash, a toothpaste, acne or wound treatment product, skin scrub, and skin defoliate agent.

A cost-effective method for recovering precious metals in circuit board components utilizes the basic principle of oxidation-reduction reaction, adopts a mixed solution of sulfuric acid and hydrogen peroxide and a mixed solution of hydrochloric acid, sodium chloride and sodium chlorate, and also adopts ammonia water and formaldehyde to reduce silver. According to the characteristic that the redox potential of gold and palladium ions is higher, the gold and palladium ions in the chlorination leaching solution are selectively reduced into elements by using a reducing agent which is low in price and moderate in reducibility, then the elements are separated through filtration to realize resource recycling.

The present disclosure is directed to a gold recovery process in which activated carbon or another carbon-based material is used to accelerate thiosulfate leaching of gold from a gold-bearing material. In some embodiments, the gold recovery process comprises providing particulate activated carbon or another carbon-based material, providing a precious metal-bearing material, contacting the precious metal-bearing material with the particulate carbon-based material, thiosulfate, an anion exchange resin, and an oxidant to form a slurry comprising a slurried precious metal-bearing material, and leaching a precious metal from the slurried precious metal-bearing material.