Tailings dry discharge screening is a key equipment for environmental
protection and emission reduction in large-scale quartz sand production lines
(with a daily processing capacity of ≥ 3000 tons). Its core function is to
dehydrate and dry discharge the washed sand tailings slurry (with a solid
content of 15% -25%), achieving tailings resource recovery and water resource
recycling (requiring tailings moisture content ≤ 18% and wastewater sand content
≤ 0.1g/L after dry discharge), directly determining whether the production line
meets environmental protection standards and resource utilization rates. At
present, many production lines have problems such as incomplete tailings
discharge, clogged screening nets, and low processing efficiency, which not only
increase the cost of tailings stacking but may also face environmental
penalties. This article starts with the core module of the device, traces the
root cause of the problem, and provides a modular optimization plan to help
improve the efficiency of dry discharge.
1、 Problem Source: 4 Core Causes of Poor Drying and Drainage Efficiency
Through the investigation of equipment operation data from multiple quartz
sand production sites, the causes of poor tailings dry screening effect are
concentrated in four core modules: firstly, poor adaptability of the screening
surface system, mismatch between screen selection and tailings characteristics,
easy blockage, and insufficient dewatering channels; The second issue is the
imbalance of vibration system parameters, insufficient excitation force leading
to insufficient material throwing and insufficient dehydration time; The third
issue is improper control of the feeding system, with large fluctuations in
feeding volume, uneven distribution of fabric, and local overload affecting the
efficiency of dry discharge; The fourth issue is the lack of auxiliary
dewatering systems, which do not combine tailings characteristics with auxiliary
methods such as flocculation and blowing, resulting in limited dewatering
effectiveness.
2、 Module wise precise optimization: from core components to system
collaboration
Module 1: Screen System Upgrade - Building a Solid Dehydration Core
Foundation
The screen surface is the key to dehydration. Traditional steel wire mesh
screens have a single aperture, poor wear resistance, and are easily blocked by
fine sand, which is the main reason for incomplete dry discharge. Optimization
plan: Select a high-frequency polyurethane screen specifically designed for
quartz sand tailings, and adopt a "multi-layer composite aperture" design (upper
coarse screen aperture 1.2-1.5mm, lower fine screen aperture 0.3-0.5mm), which
not only ensures tailings interception effect but also improves drainage
efficiency; Install raised anti slip structures on the surface of the screen
mesh to reduce material slippage and extend dehydration time; Install a
high-frequency vibration cleaning device under the sieve, with a frequency set
at 50-60Hz, to clean the residual fine sand in the sieve holes in real time,
reducing the clogging rate by more than 60%. At the same time, adjust the
inclination angle of the screen surface to 15-18 ° to balance the material
pushing speed and dehydration adequacy.
Module 2: Vibration System Calibration - Strengthening Dehydration Power
Support
The vibration system is the core of dehydration power, and insufficient
excitation force and improper frequency can directly lead to a decrease in
dehydration efficiency. Optimization plan: Replace the high-power vibration
motor (power 30-45kW), accurately control the excitation force between 120-150kN
by adjusting the angle of the eccentric block, ensure that the material can be
fully thrown and loosened, and accelerate moisture separation; Stabilize the
vibration frequency at 35-40Hz, which can effectively break the surface tension
of the tailings slurry and improve the water infiltration efficiency; Calibrate
the phase difference of the dual vibration motor to 0 °, ensuring that the
vibration trajectory is straight and avoiding insufficient local dehydration
caused by material deviation to one side. Regularly check the fastening status
of the motor fixing bolts, and control the pre tightening torque between
200-250N · m to prevent loose operation from affecting the vibration effect.
Module 3: Feeding system regulation - a prerequisite for ensuring smooth
operation
Unstable feeding is an important cause of fluctuations in dry discharge
efficiency, which needs to be optimized from both quantity control and fabric
distribution aspects. In terms of quantity control: Install electronic belt
scales and variable frequency feeders to monitor and adjust the feed rate in
real time, stabilizing it at 85% -95% of the equipment's rated value to avoid
material accumulation on the screen surface due to feed overload and
insufficient dehydration time; When the solid content of tailings exceeds 25%,
the diversion device is activated to reduce the load on a single equipment. In
terms of fabric: Install a spiral distributor and a baffle at the feed inlet to
evenly distribute the tailings slurry along the width of the screen, and control
the thickness of the material layer at 80-120mm to ensure that each part of the
material can obtain a uniform vibration dewatering space, avoiding the influence
of local thickness or thinness on the drying effect.
Module 4: Auxiliary Dehydration System Matching - Improving the Upper Limit
of Drying Efficiency
For quartz sand tailings with high fine sand content and high viscosity, it
is difficult to achieve the standard of dewatering solely through screen
vibration, and auxiliary systems need to be provided. Optimization plan: Install
a flocculant dosing device at the feed end, using anionic polyacrylamide
(molecular weight 12-15 million), dilute to a concentration of 0.1% -0.3%, and
evenly dosing. The dosing amount is adjusted according to the solid content of
the tailings (3-5g/t) to accelerate fine sand agglomeration and improve
dewatering efficiency; Install a high-pressure air blowing device above the
screen surface, evenly arrange air outlets along the length of the screen
surface, control the pressure at 0.3-0.5MPa, and blow the residual material in
the screen holes in real time to further reduce the probability of blockage;
Install scraper plates at the end of the screen surface to ensure that the dry
tailings can smoothly detach from the screen surface and avoid accumulation and
moisture regain.
3、 Optimization effect verification and daily operation and maintenance
Through the optimization of the entire module above, three core effects can
be achieved: stabilizing the moisture content of tailings below 15% after dry
discharge, meeting the standards of stackability and recyclability; The
equipment processing efficiency has been improved to over 95% of the rated
value, and a single device can meet the tailings dry discharge requirements of a
3000t/d production line; The screen clogging rate is reduced to below 5%, and
the service life is extended to over 8000 hours. Daily operation and maintenance
require checking the dry discharge moisture content, screen blockage, and
vibration motor temperature on a daily basis; Clean up residual materials on the
screen surface every week and tighten loose parts; Calibrate vibration
parameters and feed rates monthly, and replace aging seals; Conduct
comprehensive maintenance on motors and exciters every quarter to ensure
long-term stable operation of the equipment.