Continuous control of the final grinding product size is important to optimize gold liberation for gold milling operations. In addition the live monitoring of the final product particle size leads to a maximum grinding circuit throughput. This is essential for driving the overall efficiency of the operation because the process of grinding and crushing ore 8212 known as comminution 8212 is on average the highest energy step in mining. For more information refer tonbsphttpswww.ceecthefuture.orgresource-centersmart-facts.nbspnbspnbspGet A Quote
Continuous control of the final grinding product size is important to optimize gold liberation for gold milling operations. In addition the live monitoring of the final product particle size leads to a maximum grinding circuit throughput. This is essential for driving the overall efficiency of the operation because the process of grinding and crushing ore 8212 known as comminution 8212 is on average the highest energy step in mining. For more information refer tonbsphttpswww.ceecthefuture.orgresource-centersmart-facts.nbspnbspnbsp
Comminution circuits are used to optimize the liberation of valuable mineral particles from waste rock for downstream separation processes. When the target grind is not achieved under-grinding it results in a higher number of unliberated gold particles. This in turn causes a loss in gold recovery and therefore revenue. Over-grinding does not have a significant benefit to gold recovery but reduces the mill throughput and results in higher unit costs in terms of energy grinding media and reagent consumption.
If there are frequent changes in ore hardness grinding circuit performance is affected and poses challenges for operators to maintain the target particle size.nbsp Further metallurgical testing has shown that the optimal grind targets can be different for each ore type which proves an additional challenge since the mill feed can consist of either ore type of a blend and can change quickly depending on mining operations.
A particle size monitor can assist the mill operator to maximize the grinding circuit throughput as the milling conditions change due to variable ore processed at the mine.nbsp Particle size monitors use ultrasonic attenuation technology to provide particle size analysis of a mineral slurry stream. They can help ensure the final grind target at each instant of the process. Continuous real-time feedback will instantly alert the plant manager to process upsets allowing a quick reaction to lessen the impact. This helps to maximize mill throughput product quality and energy efficiency.
Maximum grinding control benefits are obtained when the particle size analyzer receives a sample from
To learn more about a specific Gold operation that improved recovery utilizing a representative slurry sampling station and particle size monitors read the case study presented at the 49th Annual Canadian Mineral Processors Operators Conference Grinding Circuit Final Grind Control at Agnico Eagle Meadowbank Mine.
Cyanide leaching process is one of the common gold ore beneficiation processes. The process index depends on factors such as gold particle size sulfide content ore block size leaching speed leaching time cyanide concentration and leaching slag washing degree. The factors that affect gold leaching include grinding fineness pH temperature cyanide dosage pulp-solid-liquid ratio leaching time impurities in ore and amount of leaching aid and so on. This article will discuss how grinding fineness influence gold leaching process and its related problems and improvement methods.
Grinding fineness refers to the thickness of the grinding product and is usually expressed by the mass fraction of the ore particles less than 200 mesh less than 0.074 mm in the total grinding product.
In general the determination of grinding fineness is related to embedded relationship of the ore. The embedded shapes and particle sizes of different ore have an impact on the determination of grinding fineness. Take a gold mine as an example and do related gold leaching experiments
The main metal minerals in this gold ore are natural gold pyrite hematite limonite poisonous sand etc. and the gangue minerals are mainly dolomite malachite quartz mica etc. The main elements of its ore are as follows
The whole test of gold leaching process first pour the raw ore ground to a certain fineness into the JT-80 type leaching mixing tank then add a certain amount of sodium cyanide adjust the mass concentration of the pulp to 33 and then add lime to adjust the pH to 11.5. After leaching at 18C for a certain period of time aspirate the supernatant liquid wash and dry the dross and finally analyze the gold grade of the dross to calculate the gold leaching rate. Here we judge the leaching effect by comparing the gold leaching rates.
The grinding fineness test was carried out under the condition that the amount of sodium cyanide was 1 kg t and the leaching time was 24 hours. The results were analyzed by observing the effects of different fineness on the gold leaching process. The following sets of data were obtained in the experiment
From these sets of data it can be seen that the grinding fineness has a greater impact on the gold leaching rate. With the increase of the grinding fineness the gold leaching rate increases first and then slowly. It can indicate that increasing the grinding fineness is beneficial to release of gold minerals from the inclusions. Take into comprehensive consideration a 325 mesh accounted for 95 is a more suitable gold leaching grinding fineness.
The above experiment can determine that a 325 mesh accounted for 95 is a more suitable gold leaching grinding fineness. However in the actual gold leaching operation the grinding fineness will also be affected by other factors which will indirectly affect the gold leaching results. Therefore how to avoid or reduce these problems is also important. The following are the factors that affect grinding and the methods to improve them.
Crushing particle size and grid sieve adjustment Crushing particle size and grid sieve adjustment are also one of the factors that affect the grinding fineness in the gold leaching process. This requires the ball miller to do a good job of the supervision of the crushing system. If the grain size of the ball mill changes during production it must be reflected to the crushing workshop immediately. Ultimately the crushing particle size is required to meet the requirements of the mill to reduce the power consumption of the ball mill.
Mineral processing is a major division in the science of Extractive Metallurgy. Extractive metallurgy has been defined as the science and art of extracting metals from their ores refining them and preparing them for use. Within extractive metallurgy the major divisions in the order they may most commonly occur are Mineral Processing or Beneficiation Hydrometallurgy Pyrometallurgy and Electrometallurgy. The last steps in the winning of metals are in Physical Metallurgy where the composition and treatment of metals are varied to provide desired physical and mechanical properties.
In mineral processing a number of unit operations are required to prepare and classify ores before the valuable constituents can be separated or concentrated and then forwarded on for use or further treatment. The field of mineral processing has also been given other titles such as mineral dressing ore dressing mineral extraction mineral beneficiation and mineral engineering. These terms are often used interchangeably.
Oreis a term used to describe an aggregate of minerals from which a valuable constituent especially a metal can be profitably mined and extracted. Most rock deposits contain metals or minerals but when the concentration of valuable minerals or metals is too low to justify mining it is considered a waste or gangue material. Within an ore body valuable minerals are surrounded by gangue and it is the primary function ofmineral processing to liberate and concentrate those valuable minerals.
Generally mineral processing begins when an ore is delivered from a mine to a processing facility. At this point the ore is calledrun-of-minematerial because there has been no treatment performed on it.
The general focus of this document will be on metaliferrous ores represented by run-of-mine material described in category 3 above. An exception to the above discussion of mineral processing arises when the valuable component of the ore is extracted directly by chemical methods. The most common and notable example of this are precious metal values gold silver etc. where the beneficiation process is applied directly on run-of-mine ores followed by the extraction of gold and in some cases silver as a relatively pure metal within the mineral processing circuit.
2.0 Processing Approach and MethodIn broader terms mineral processing consists of two functions. Firstly it involves the preparation andliberation of the valuable minerals from waste minerals and secondly theseparationthese values into two or more products called concentrates. The term separation in this case is synonymous withconcentration. These functions are carried out within the constraints of the following three rules.
The flowsheet in Figure 1 shows diagrammatically the typical sequence of operations in the process plant. The various unit operations used for liberation and separation will be discussed in the following sections.
In order to separate the minerals from gangue the waste minerals it is necessary to crush and grind the rock to unlock or liberate valuable minerals so that they are partially or fully exposed. This process of size reduction is called comminution. The crushing and grinding process will produce a range of particles with varying degrees of liberation Figure 2. Any particles that exceed a target size required for physical separation or chemical extraction are returned to the crushing or the grinding circuit.
The comminution process actually begins during the mining stage through the use explosives excavators or scrapers for softer material. This is necessary in order to generate a material that is transportable by haul trucks or conveyors. Comminution in the mineral processing plant is carried out in a sequential manner usingcrushersand screens followed bygrinding millsandclassifiers. The various types of comminution equipment including their general application are described in detail below.
Copyright © 2020 Finsa Machinery Company All rights reserved