Modeling and Improving the Efficiency of Crushing ...

1. Introduction

Worldwide practice shows that economic development is based on the concept of efficient functioning. An essential aspect of such a function is the rational use of energy resources [ 1 ]. Irrational use of energy leads to economic losses and the exhaustion of energy resources.

The mineral and raw material complex plays a leading role in Russia’s economy, as a factor in its steady development. It is no wonder that mining and processing companies are the largest consumers of electricity [ 2 ]. More than 3 billion tonnes of raw materials are crushed every year. More than 70 billion kWh of electricity is consumed, representing up to 5% of the country’s total production. For a single mine, the share of energy consumption for crushing can be as much as 50% of the annual output. In the context of the upward trend in energy prices over the last few years, most mining companies are focused on reducing energy consumption in order to cut the cost of the final product [ 3 ].

The crushing process is widely used in the metallurgical, construction, and mining industries. The basic method of primary preparation of raw materials is to crush the mined ore. Crushing is the first and most important stage in the preparation of raw materials for further processing. The quality of the following processing stages (crushing, flotation, thickening, drying, etc.) depends on the crushing quality. The main purpose of this stage is to separate (open) the grains of different minerals contained in the mineral, which are closely intertwined and fused together during the process of formation. Therefore, the more completely the minerals are exposed during crushing, the better and more successful the subsequent beneficiation of the mineral is. The crushing stage cannot be avoided and therefore improving crushing efficiency is an urgent industry concern. A significant drawback of crushing units is their low energy efficiency.

A characteristic feature of the crushers is their continuous function. The desired degree of material reduction is to be maintained while the volume of the feed material is constantly controlled.

The aim of this work is to develop a mathematical model of the crushing process and to set out the dependencies between the main technological parameters of the machine.

To achieve the objective, the following tasks should be carried out:

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Research the modelling and automation of crushing equipmentcrushing equipment.

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Develop a mathematical model of a cone crusher.

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Identify the effect of plant capacity on the crusher’s current and drive power.

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Find out the crushing process conditions for energy efficiency.

The scientific novelty lies in finding the dependence of the current and power of the crusher on the feeder capacity. This will form the basis for the study of operating modes and the formation of requirements for an automatic control system. As a result of the study, it is established that the dependence between the crusher motor current and crusher capacity has a linear nature. The parameters of this dependence are defined, and the adequacy of the model is estimated. The obtained mathematical model can be used to select optimal values of the control parameters to improve crushing efficiency, as well as to develop automated control systems for the crushing process.

Your crushing operation changes with portable crushing equipment

This article helps you understand what changes when choosing a portable crusher. There is no better or worse type machine but the right tool for your application.

You Will Move Less Often with a Portable Crusher

The most noticeable difference between a portable crusher and a mobile crusher is mobility. A portable crusher is mounted on a chassis with wheels and can be moved with a tractor from job to job. In many cases it requires multiple loads to move also additional discharge and transfer conveyors and portable screening plants. Once a portable crushing plant is setup on the job it hardly leaves its spot which requires you to be able to bring material to the crusher. Mobile crushers are track-mounted machines that are self-propelled that can be moved anywhere, anytime without the need of any support equipment. Mobile crushers are moved with a lowboy trailer and can be setup quickly. Larger track mobile crushing plants break down for transport and require more moves. Compact mobile crushers can be moved with a single load.

Even onsite a mobile crusher can track quickly to a new location (e.g. back up closer to the material or move to a different material pile).

Without mobility, you...

• lose money on machine setup time
• limit yourself on the range of jobs you can accomplish
• are required to haul material to the crusher

You Will Tackle Large-Scale Crushing Jobs

The burden associated with moving portable equipment results in higher indirect spending associated with trucking, labor, and setup. These additional costs must be absorbed before profits are generated. Therefore, you need more tonnage to compensate for additional costs. Hence, you will find portable equipment in quarries processing the same material in a high-volume day in and day out, where moving is not necessary.

Without the ability to do also smaller jobs, you ...

• are competing on big jobs on a cost per ton basis whereas on smaller jobs you might be able to charge higher per ton rates or even daily rates
• can't benefit from onsite crushing smaller volumes
• lose out on ad-hoc business

Portable Crushing Equipment Requires More Real Estate

Some portable crushers require additional portable screening plants and transfer and discharge conveyors. This takes up more space on the job and makes it difficult to setup on certain jobsites. While this doesn't matter in a wide-open quarry it can be a burden on a tight jobsite. Mobile crushers are more compact because they need to fit on a lowboy trailer. The relatively small footprint makes it easier to place a machine on the jobsite.

Without a compact operation you...

• limit yourself on the range of jobs you can tackle
• struggle to setup your crushing spread
• paths around the crushing operation become longer

An Abundance of Space Results in a Bigger Machine

Mobile crushing equipment is designed so that everything fits in between 2 tracks that fit onto a lowboy trailer whereas a portable crusher is a trailer. As a result, you can design a portable crusher with wide openings and more clearances for better accessibility and material flow. The compact nature of a mobile crushing plant puts components much closer to each other which makes it harder to get access to certain components. However, manufacturers have put a lot of effort in finding ways to make access easier. Components lower and fold hydrulically for better access, or they might swing out or open up to improve accessibility.

Portable crushers feature larger feeders, wider conveyors, and large on-board screening plants with 2 or 3 screen decks allowing multiple products to be produced simultaneously. This translates to a large throughput capacity.

Without a large and open design, you...

• create bottle necks and limit production
• struggle with accessing components
• struggle to feed with a wheel loader

Paths Around a Portable Crushing Plant Are Longer

When operating a portable crushing plant you need to make sure that new feed material is brought continuously to the machine which can result in long loader round-trips. Also walking around the plant for daily maintenance and repairs become longer and you find yourself climbing ladders all the time. Access is generous but high up.

Without short paths, you...

• waste time running around
• risk safety when lifting heavy parts, power tools, or bulky screen-media onto a portable crusher
• risk running empty when material is not there

• waste time running around
• risk safety when lifting heavy parts, power tools, or bulky screen-media onto a portable crusher
• risk running empty when material is not there