A medium-sized mobile cone crusher processes granite into a 5–20 mm size fraction at a capacity of 180–320 tonnes per hour; its performance is influenced by the hardness of the granite, the feed rate and the moisture content; There are various classes of crushers; maintenance every 200 hours ensures consistent performance.
When processing granite with a bulk density of 1.6 t/m³ and an initial feed size of up to 210 mm into the 5–20 mm fraction, the throughput of a standard mid-range mobile cone crusher ranges from 180 to 320 tonnes per hour; this is the engineering reference range.
The main factors determining the final output include the hardness of granite on the Mohs scale; standard granite has a hardness of between 5.5 and 7 – these are measured values – whereas at a hardness value above 6.5, productivity decreases by 15–20% relative to the baseline value; these are calculated figures. The rate is also affected by the uniformity of material feed into the feed hopper; if the feed deviates from the nominal value by more than 10%, productivity falls by 8–12%; these are measured data.
To obtain the target particle size range of 5–20 mm, a medium crushing mode is usually employed with a gap between the cones of 15 to 25 mm; this is the official specification. when the gap is set to 15 mm, the throughput ranges from 180 to 240 tonnes per hour, whilst when set to 25 mm, the figure increases to 260–320 tonnes per hour; this is the engineering reference range. At the same time, the proportion of the finished fraction in the output is at least 85% of the total volume of material produced; this is the measured data.
The specifications list includes the following items: Crusher class: Small, Medium, Heavy. Nominal throughput for 5–20 mm granite: 90–150 t/h, 180–320 t/h, 350–550 t/h (this is the engineering reference range) Maximum feed size 120 mm 210 mm 300 mm (these are the official specifications) Proportion of finished fraction in the output 82% 85% 88% (these are measured data).
First question: How does the moisture content of granite affect the crusher’s performance? Answer: When the material’s moisture content is 3% or less, performance figures remain unchanged; whilst at moisture content levels above 5%, performance decreases by 10–15% due to material sticking in the crushing chamber; these are actual test data. Second question: Is it possible to increase throughput beyond the specified values? Answer: Increasing throughput beyond the upper limit of the specified range leads to an increase in the proportion of non-standard particles larger than 20 mm by more than 20%, which does not meet the quality requirements for the finished product; this is the engineering reference range. Third question: How often does the crusher need to be serviced to maintain stable throughput? Answer: Scheduled maintenance every 200 operating hours allows throughput to be maintained at a level of at least 95% of the nominal value; this is the official specification.
