STUDY OF SEDIMENTS OF COLLECTING AGENTS IN ELEMENTARY FLOTATION ACT

The operating mechanism of physically sorbed derivatives of collector obtained at a nonstoichiometric ratio between collecting agents with heavy metal salts is proposed. It is found that by changing the ratio of the components, it is possible to adjust their surface-active properties with respect to the gas-liquid interface and, consequently, the ability to remove the kinetic restriction to the formation of flotation contact. The physical form of sorption on a mineral can be represented by collector sediments and ion-molecular associates. The research results show that when the interlayer breaks through, these forms can desorb from the mineral and spread over the bubble surface, dragging the liquid from the interlayer into motion, thereby “drying” the mineral surface. In turn, the removal of liquid from the interlayer leads to a reduction in the induction time, which affects the efficiency of flotation. The results make it possible to reveal the mechanism of flotation activation with heavy metal salts and can be used in the development of fundamentally new engineering solutions.

SYNERGISTIC EFFECT OF A COMBINATION OF COLLECTORS IN ADSORPTION AT GAS-LIQUID INTERFACE

The promising nature of flotation with a combination of collecting agents is well known. The synergetic effect of combinations of collectors develops as hydrophobization of a mineral surface during adsorption and as reduction in surface tension at gas-liquid interface. The earlier proved mechanism of physisorption of an agent is based on the connection of its surface characteristics (surface pressure, spreading rate) and their collectability. It is assumed that the ratio of agents in their combination for flotation can be selected from the maximum synergistic effect achieved. This study focuses on adsorption at the gas-liquid interface in aqueous solutions of binary mixtures of sodium lauroyl sarcosinate and hexadecyltrimethylammonium bromide. The interaction parameters and the ratio of the components in the solution so that the maximum synergistic effect is achieved are determined.

The Intoxicant as Preservative and Scientific Instrument in the World of James Petiver

This article examines the emergent use of alcohol as a preservation medium for scientific specimens from the mid-seventeenth century in Britain. Taking the work of the London apothecary James Petiver (1660–1718) as its focus, the article explores the ways in which alcohol was used to fix and remediate the specimen, shown ‘lifelike’ in glass, in displays or in engravings. Petiver actively promoted the use of pickling spirits, publishing instructions on how to preserve specimens and distributing these to his collecting agents in the Indies trade. The article introduces the early history of preservation in alcohol in England, and particularly the work of Robert Boyle in promoting the wet collection. It then follows Petiver's agent, Richard Bradley, on his 1711 visit to Leiden and Amsterdam, examining the role of alcohol alongside other means of preserving and activating the scientific collection.

Recent Development on Herder Commercialization

Herders (also known as surface collecting agents) are made of surface active compounds (surfactants). They reduce the surface tension of water and thereby change the spreading behavior of immiscible liquids, such as an oil slick, floating on the surface. Oil slicks that have spread too thin to burn can be re-thickened if herders are sprayed on the water surface around a slick. Once the slick is thickened, it is amenable to in situ burning without the need for fire-resistant boom. Herders are listed as surface collecting agents on the National Contingency Product Schedule administered by the US Environmental Protection Agency (USEPA, 2019) for use in US waters. Herders are commercially available and oil spill response organizations have the capability to utilize herders. A new joint industry / government agency project was recently initiated to develop a novel herder delivery and ignition system. The initial plan is to develop a remotely operated surface vehicle (RSV) that will deliver herder from an onboard reservoir and a system to ignite herded slicks. The RSV we are developing has 10–12 hours of operation time, a range of 500 miles and can travel at speeds of up to 65 miles/hour. The RSV can be deployed from a helicopter that has a cargo hook, a boat, and potentially a fixed-wing aircraft that has an appropriately sized hatch. The vision is rapid deployed to a remote spill location using a helicopter (or a fixed-wing aircraft) and operated from this platform until a response vessel arrives on the scene. The response vessel can then take over RSV control freeing the aircraft for other duties. This paper will describe the planned development and testing of the RSV and other progress toward herder commercialization.

An Overview of Calcite Recovery by Flotation

In general, precipitated calcium carbonate (PCC) is used as a mineral filler in paper industries; while natural calcite (CaCO3) ore is also suitable for industrial use if it is a finely ground high-grade material. Naturally, calcite is found in the form of high- or low-grade ores and it is one of the most widely distributed industrial minerals on the earth’s crust. However, it is rarely found in its pure form and is generally associated with other gangue minerals; the type and percentage of which vary from one deposit to another. These minerals are generally separated by flotation and/or magnetic separation (in the case of iron impurities). Calcite ores typically contain metal sulphide, silicate, or other calcium-containing impurity minerals, which can be removed by flotation. A tremendous amount of research has been performed on refining the flotation process for calcite ores and designing the reagents (specifically, collectors) to increase the efficiency of the process. Metal sulphide/silicate impurity minerals can be removed by the froth-flotation process using amines and xanthate collectors. Alternatively, fatty acids are used as collectors to float calcium-type minerals directly from the ore. This paper reviews the industrial practices and fundamental research related to collectors surrounding calcite ore flotation. This article presents and reviews collectors for the beneficiation of high-grade calcite ores which have been reported in the literature in order to assist judicial choice of collecting agents in flotation.

Collecting Agent–Mineral Interactions in the Reverse Flotation of Iron Ore: A Brief Review

Froth flotation has been widely used in upgrading iron ores. Iron ore flotation can be performed in two technical routes: direct flotation of iron oxides and reverse flotation of gangue minerals with depression of iron oxides. Nowadays, reverse flotation is the most commonly used route in iron ore flotation. This review is focused on the reverse flotation of iron ores, consisting of reverse cationic flotation and reverse anionic flotation. It covers different types of collecting agents used in reverse iron ore flotation, the surface characteristics of minerals commonly present in iron ores (e.g., iron oxides, quartz, alumina-bearing minerals, phosphorus-bearing minerals, iron-bearing carbonates, and iron-bearing silicates), and the adsorption mechanisms of the collecting agents at the mineral surface. The implications of collecting agent–mineral interactions for improving iron ore flotation are discussed.

THE EFFECT OF DIALKYLDITHIOPHOSPHATE REAGENTS ON COPPER FLOTATION FROM PYRITIC SLAGS

The paper studies the patterns of copper slag mineral phase separation by flotation depending on the modification of the additional BTF series collecting agent (dialkyldithiophosphate derivatives) and the ratio of main and additional collecting agent consumptions. The results of open and locked-cycle laboratory flotation tests are presented, and the effect of pulp pH on copper extraction is observed. The reasons for the copper extraction gain during grinding and subsequent flotation in acidic medium are analyzed. The aggregates of copper and iron sulfides are identified in slags thus proving decoppering effectiveness with a decrease in pH to slightly acidic values due to the active flotation of intergrown pieces of copper-containing phases with iron sulfide (pyrite, pyrrhotine). It is shown that the additional BTF series collecting agent added to the main collecting agent – potassium butyl xanthate – makes it possible to reduce the total consumption of the combined collecting agents while maintaining copper extraction and concentrate quality as compared to the consumption of only xanthate necessary to achieve the same parameters. The best results were achieved with the use of the BTF 1614 reagent in combination with potassium butyl xanthate at the BCC : BTF = 3 : 1 ratio. At an optimum pH = 5,5÷6,8, the increase in copper extraction to the concentrate was 11.13%, and gold and silver extraction increased by 9.68% and 9.93%, respectively.