EA034597B1 - Method of gravitational enrichment of minerals in static aquatic environment - Google Patents

Abstract

A method to separate minerals in a static aqueous medium is proposed. Pulp or its components separately: water and a mixture of minerals, is fed into a vessel. Due to different vertical speeds, depending on the density of particles, minerals are dispersed in water. Denser particles precipitate lower, those less dense remain above. Then the vessel is rotated so that the vertical motion vectors of the particles intersect with the side wall of the vessel. As a result, minerals will settle on this wall, fixing the order of separation according to their densities. The practical implementation of the method involves the use a rotating drum, whose inner cavity is divided into separate, non-communicating vessels.

Description

Description of the invention

The alleged invention relates to the technology of gravitational enrichment of minerals and is aimed at extracting fine gold.

As you know, gravitational enrichment (GO) of minerals is the separation of minerals by density in the field of gravity or centrifugal forces to separate waste rock and obtain concentrate. When civil defense uses the force of gravity (hence the name of the method); sometimes fields of centrifugal forces or electromagnetic forces are additionally attracted (1).

GO can be carried out in water and air. In the aquatic environment, separation occurs more clearly, which is associated with a higher density of water. Therefore, wet enrichment has the greatest practical application.

The calculation of GO is based on the determination of the relative velocities of particles moving, which differ in density, size and shape in media of different density and viscosity. The free fall velocity of single particles Vo can be expressed as

Vo = kd ⁿ (δ-Δ) ^ηι / Δ, where k, n, m are variables experimentally determined quantities;

d is the particle size;

δ and Δ are the density of the particle and medium, respectively.

For the smallest particles, the effect of medium viscosity μ is taken into account

Vo = kd ⁿ (δ-Δ) ^ηι / μ.

Several methods are known for isolating the heavy fraction of minerals based on the difference in vertical velocities of the mineral particles. These include jigging, concentration on tables and locks, enrichment in hydrocyclones, gutters, etc. All of them are implemented in a moving water stream. The closest in technical essence to the claimed invention is a method carried out in a stream of water flowing along an inclined plane (gutters, locks). In this case, the vertical velocities of particles from the influence of gravity vectorly add up to the speed of the water flow. Due to the difference in these resulting velocity vectors, the particles are dispersed depending on their density along the length of the trench. In the upper part, denser particles settle, in the lower - less dense particles.

The disadvantages of this method, as well as other of the above, is the difficulty of assessing the influence of unevenness and turbulence of the water flow in the mathematical description of the process and, as a result, the difficulty of controlling it to achieve the desired result. A method with acceptable positive indicators works in the enrichment of large fractions of minerals. For small fractions, fine-filling floodgates with a reduced water velocity are used (2). But the presence of a water stream, a priori, entails the removal of not only light waste rock, but also small particles of heavy metals.

The process is greatly simplified and becomes the most predictable, manageable and, as a result, more effective if it is carried out in a static aquatic environment. Indeed, if a mixture of particles of different densities is poured into a vessel with water (Fig. 1a), then only the gravitational force will act on them. After a certain period of time, the particles will be distributed vertically depending only on the values of their density (Fig. 1b). Since denser particles will have a greater settling rate, denser particles will appear below, less dense particles at the top. The influence of particle sizes on the settling rate is minimized through the use of a narrow size class. If at this moment the vessel is rotated so that its lateral surface intersects with the vertical vectors of particle motion (Fig. 1c), then the mixture will settle on this surface, while maintaining the obtained disintegration result (Fig. 1d). After draining the vessel, the minerals can be extracted with fractionation depending on their densities.

The logic of the above reasoning is also valid for the situation when pulp is immediately fed into the vessel, which is a mixture of mineral particles with water. In this case, only the starting conditions of the process change. A certain amount of light minerals will initially be distributed over the entire height of the vessel, which will lead to a slight additional clogging of the heavy fraction by them. A similar initial distribution of the heavy fraction not only does not entail negative consequences, but even has a positive effect on the final result.

Practical implementation of the method

Practical implementation of the method can be carried out on a device that consists of a rotating drum, represented by two side flanges, divided by partitions into sectors (Fig. 2). Sectors of adjustable geometry by changing the position of the partitions, which together with the ability to change the mode and speed of rotation of the drum allows you to control the process of separation of particles.

The process is as follows. When the next sector of the drum is in an upright position (pos. I), it is filled with water and a mixture of solid minerals is fed into it or the sector of the drum is filled with the finished pulp. The process of dispersal of mineral particles begins due to the different-speed drop caused by the difference in their density in a static aqueous medium. Then

- 1 034597 start to rotate the sector by rotating the drum. To achieve the desired result, the rotation mode can be programmed and controlled by the drum brake. The rotation of the drum itself can be carried out on the principle of a water wheel or through an external drive.

Due to the rotation of the sector, the vertically dispersed mixture settles on the partition of the sector, preserving the dispersal configuration. Due to the slope of the sector, a gradual outflow of water from it occurs (pos. II-IV). Since the spout comes from the upper part of the sector, particles with the lowest density, which by definition are waste rock, will be removed together with water. Thus, when the septum of the sector occupies a horizontal position, part of the light fraction will already be removed from it, and the rest will be located on the peripheral zone of the septum and can be easily washed off with a stream of water in position V. The spilled pulp and washout are sent to the tails. The heavy fraction is formed in the zone adjacent to the central part of the drum, which is separated from the peripheral powder, the position of which can change during tuning depending on the specific conditions. The heavy fraction is washed off with a stream of water in the position of the sector located at positions VII-IX and sent to the concentrate hopper.

Used sources.

1. Geological encyclopedia. Gravity enrichment https: // dic. academic.ru/dic.nsf/enc_gelog/158 8 / Г gravitational enrichment.

2. Studopedia. Fortification at the gateways https://studopedia.ru/5_155268_obogashchenie-nakontsentratsionnih-shlyuzah-i-zhelobah.html.

Claims (1)

CLAIM A method of separating a mixture of solid minerals, depending on their density, in a static aqueous medium, comprising feeding a mixture of minerals into a container with water or feeding the finished pulp into a container and ensuring the dispersal of mineral particles vertically due to the difference in their rates of drop in water, different the fact that the plane of one of the walls of the tank, on which the particles are deposited, is divided transversely in height into two parts by a powder, the location of the powder is set depending on the composition of the planned processing raw materials, while switching to raw materials processing with a significant change in composition, the location of the nut is adjusted, after filling the tank with pulp, the particles are dispersed vertically due to the difference in the rates of particles falling in water with deposition of the required amount of heavy fraction of particles on the wall with the nut, the tank the separated mixture is rotated, tilting towards the side wall with the nut, as a result of which the top layer of pulp is continuously drained with a light fraction of particles, the cat they direct the tail into the tails, periodically test the tails and, according to the results of testing, adjust the angular velocity of rotation of the tank, carry out a further turn of the tank with the sediment settled in the bottom zone in such a way as to bring the wall with the nut into a horizontal position and ensure a state of the mixture in which the settled into the bottom zone, the particles of the mixture are dispersed in a dehydrated state in accordance with their density in such a way that a heavy fraction is located in the inner part behind the threshold, in the peripheral part - a lighter, further rotation of the tank is carried out using external irrigation of the dehydrated mixture of particles in such a way that as the wall tilts increase, the peripheral part containing the light fraction, which is sent to the tails, is washed off first and at the last stage of the turn, when the wall of the tank goes inverted position, wash off the heavy fraction located inside from the nut, and direct it to the hopper of the productive concentrate.