Mineral Processing Engineering

Grinding Mill Design & Ball Mill Manufacturer

All Grinding Mill & Ball Mill Manufacturers understand the object of the grinding process is a mechanical reduction in size of crushable material. Grinding can be undertaken in many ways. The most common way for high capacity industrial purposes is to use a tumbling charge of grinding media in a rotating cylinder or drum. The fragmentation of the material in that charge occurs through pressure, impact, and abrasion.

Grinding is converting energy: When the grinding charge is forced to tumble the motor energy is converted into new particle surface and heat.

An important point for the economy is that the size of the grinding media suits the material to be ground.

The choice of mill design depends on the particle size distribution in the feed and in the product wanted. Often the grinding is more economic when executed in a primary step, followed by a secondary step, giving a fine size product.

As experts in crushing and grinding – can offer a full range of grinding mill types and sizes. Our mills are identified by codes of letters:

C=central trunnion discharge
P=peripheral discharge
R=spherical roller trunnion bearing, feed end
H=hydrostatic shoe bearing, feed end
R=spherical roller trunnion bearing, discharge end
K=ring gear and pinion drive

CRRK

By David| 2017-08-17T08:39:51+00:00 February 20th, 2017|Categories: Crushing & Screening|Comments Off

Flocculant Mixing System & Dosage Strength Dilution

By David| 2017-09-20T12:19:50+00:00 September 20th, 2017|Categories: Thickening|Comments Off

How Temperature Affects Copper Sulphate & Cyanide Adsorption of Xanthates at Mineral Surface

Different parts of the world in which mineral separation by flotation is practiced experience vastly different natural temperatures, and in some districts there is a big difference between summer and winter temperatures. It will be shown in this paper that the temperature is of considerable importance where it is desired to separate pyrite or arsenopyrite from other minerals. It is probable that some of the differences obtained in the flotation of these minerals at plants working under otherwise similar conditions are due to temperature variations. The influence of temperature on the flotation of galena, chalcopyrite and sphalerite by xanthates is less marked than its influence on pyrite flotation.

Experimental Method

The methods used have been described previously. In each test the clean mineral specimen was immersed in a solution prepared by adding the reagents in the following order:

sodium carbonate and hydrochloric acid as necessary to buffer the solution and to give approximately the pH value desired,
sodium cyanide,
copper sulphate,
ethyl xanthate, followed by
a final adjustment of pH value.

After ½ hr. the mineral was tested for a xanthate film by bringing a bubble of air into apparent contact with the submerged polished surface. If true contact (spreading) was not

By David| 2017-09-15T07:22:25+00:00 September 15th, 2017|Categories: Reagents & Chemicals|Comments Off

Bad SAG Mill Liner Design

By David| 2017-09-14T20:01:39+00:00 September 14th, 2017|Categories: Grinding|Comments Off

Placer Prospecting

Placer Prospecting Practice

Prospecting methods have been developed and well established within the last few years. Sinking pits and shafts generally gives good results, but this work is usually expensive and generally slow and troublesome, owing to the presence of water in most placer ground or to the necessity of timbering the shafts. With the large amount of water flowing in from the bottom of the shaft, together with the running ground, it is most difficult to get an accurate sample of the ground. Owing to the troubles mentioned, the pits are often too few in number to determine accurately the actual mineral content of the ground in question.

The drilling method has generally been adopted, on account of the greater number of holes that can be sunk at a comparatively small cost. The mineral contents can be accurately determined by this method, granting of course, that the man in charge of the work is experienced and fully competent to make his estimates. The number of holes to be drilled in a certain area of ground cannot be determined beforehand; it will depend on whether the valuable metals or minerals appear to be generally and evenly distributed over a large area of

By David| 2017-09-12T13:03:12+00:00 September 12th, 2017|Categories: Geology, Gravity Concentration|Comments Off

Placer Mining Equipment

Hydraulic Mining

Where it is practicable, this is the simplest and most inexpensive method of placer mining. The mechanical equipment requirements consist only of pipe lines and giants. One feature, however, that is frequently overlooked in hydraulic mining is the matter of dumping facilities. This should always receive careful consideration. It often happens that there is not sufficient grade to provide a tailing dump and mechanical means have to be provided accordingly. Occasionally a mechanical tailing elevator is used, consisting of a line of dredge buckets, a centrifugal pump, etc. The hydraulic gravel elevator, however, has found more general favor, especially where there is ample water under sufficient head to operate the elevator successfully.

The hydraulic elevating method is applied with excellent success in placer mines where the boulders are so large that it is impossible to handle them with a dredge and where the bed rock lies so flat there is insufficient grade to provide a tailing dump.

Hydraulic Elevators

The Empire Hydraulic Elevator is the simplest and the cheapest apparatus for lifting gravel, that has so far been devised. There are no working or moving parts in the elevator

By David| 2017-09-12T13:46:59+00:00 September 12th, 2017|Categories: Gravity Concentration|Comments Off

Placer Gold Dredges

Steam Electric Dredge

There can be no question that the most efficient and economical method of operating a dredge is to have all the units electrically driven by individual motors and where electric power is available, the question of motive power presents no difficulty. Where such power is lacking and a self-contained steam driven dredge is required, then our steam-electric driven type should be used.

In order to obtain a self-contained dredge with its power plant on board, several attempts have been made by others in the past to use gas or oil engines, but these attempts have not proven very successful. Such engines are too delicate for the rough work involved in gold dredging. They are exceedingly heavy and the usual vertical type racks the hull in bad shape. It is almost impossible to put foundations under these engines that are heavy enough to absorb the shock of the explosions. Furthermore, it is essential that these engines be kept free from dust and dirt, and this is practically impossible on a dredge. Sooner or later fine grit is certain to work its way into the cylinders and bearings, eventually causing them to wear out. In a few instances the

By David| 2017-09-12T13:03:00+00:00 September 12th, 2017|Categories: Gravity Concentration|Comments Off

Dredge Mining for Gold

A Modern Idea of Service

Our present plant was designed and built by ourselves and we have also designed and built much of our special machinery in order to take care of the operations peculiar to our line of work. Our plant is electrically operated throughout and every modern method and apparatus has been installed in order that we might lead all others in this particular industry.

The location of our plant at Yonkers, N. Y., directly on the Hudson River, provides great advantages both to ourselves and to our clients, as it gives us both rail and water transportation. We are located in the center of production of all the materials entering into the construction of our dredges. Almost all parts of the modern dredge are of cast, wrought, or manganese steel, all of which are produced in the East and at our very door. Our location on tidewater again provides exceptional shipping facilities as our dredge machinery can be loaded directly into vessels at our dock for shipment to any part of the world. A switch from the New York Central Railroad runs through the center of our plant.

We have provided the above advantages in order that we

By David| 2017-09-14T10:17:44+00:00 September 12th, 2017|Categories: Gravity Concentration|Comments Off

Ore Concentration Practice of the Consolidated Mining Smelting

Three mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd.: (1) The Sullivan Concentrator, Chapman Camp, B. C. (near Kimberley, B. C.), (2) the St. Eugene Concentrator, Moyie, B. C., and (3) the Tadanac (Customs) Concentrator, Trail, B. C. Differential flotation is the only concentration method employed in all three plants. Tables are used for pilot work only.

Values in wall ores treated are as minerals of some, or all of the metals —lead, zinc, gold or silver. Occasional customs ores contain small amounts of copper. Sulfide iron content of ores treated varies from a low figure in some ores to 38 per cent, iron in Sullivan ore. Gangue minerals vary considerably. A few customs ores are somewhat oxidized and as a result present difficulties.

Flotation equipment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sullivan Concentrator.

In this paper I will not detail treatment nor equipment in any of our plants but will describe special features in, or in connection with, all of them. I will then deal with flotation

By David| 2017-09-10T15:36:16+00:00 September 10th, 2017|Categories: Smelting - Melting - Refining|Comments Off

Shaker Table Washability Curves

Although direct comparison of table performance with jig performance gives only a general idea as to the efficiency of tables, a better understanding of the subject can be obtained from a consideration of table efficiencies in relation to the washing difficulties reflected in the washability curves of various coals. Numerous methods of interpreting washability curves have been suggested by coal-washing engineers from time to time, and one method, which has become fairly well known in the last 8 or 10 years, is capable of giving a rather definite measure of the difficulty of washing any given coal to any desired ash content. Credit for developing this method should be given B. M. Bird, Chief Concentration Engineer, Battelle Memorial Institute, Columbus, Ohio, and those associated with him in his work at the Northwest and Southern Experiment Stations of the Bureau of Mines in 1928 and 1929. The method was first described by Bird in 1928. A more detailed explanation of the curves on which this method of interpretation is based has been presented by Coe. The method is based on the simple principle that production of a washed coal of a certain ash content depends almost entirely on how the various

By David| 2017-09-06T17:44:15+00:00 September 6th, 2017|Categories: Gravity Concentration|Comments Off

Titanium Castings by Sand Molding Process

Objective

To produce industrial-grade titanium castings by processes that are nonpolluting and lower cost than the currently used rammed-graphite process.

Approach

Foundry-grade zircon and olivine sands, bonded by waterglass or bentonite, are used to make shell or rammed molds which require relatively low-drying temperatures and do not generate noxious fumes during drying or casting.

Procedures

Three separate processes have been developed which meet the stated pollution and cost goals.

These are:

Waterglass-bonded rammed zircon or olivine sand molds are dried at 480° F, zirconia washed, redried, and used in an inductoslag or skull-casting furnace.
Waterglass-bonded zircon or olivine sand shell molds arc formed at 560° F, cured at 620° F, zirconia washed, dried at 480° F, and used in an inductoslag furnace.
Rammed zircon and olivine sand molds are bonded with western bentonite, zirconia washed, dried at 980° F, and used in an inductoslag or skull¬casting furnace.

Test Results

Industrial-grade castings were made by all three processes. However, process 1 molds have very little green strength and must be handled carefully until dried. Process 2 molds have good initial strength and are formed on heated patterns. However, shell mixes have