Project name: annual output of 40,000 tons of high-purity quartz sand project
Construction unit: Wuyi Shengjing stone new materials***
Project: Create a new project.
Project address: No. 3, Rose Road, Baihuashan Industrial Functional Zone, Wuyi County Economic Development Zone, Jinhua City, Zhejiang Province (Baihuashan Factory) Plot 7, Equipment Manufacturing Park, Wuyi County Economic Development Zone, Jinhua City, Zhejiang Province (Shuxi Factory).
The total investment of this project: the total investment of this project is 108734 million yuan.
Main process: raw material - sorting - washing - rough crushing - sand making - magnetic separation - flotation - pickling - chlorination purification.
Main equipment: hammer crusher, impact crusher, screening machine, magnetic separator, flotation machine, air energy water heater, pickling kettle, centrifugal dehydration device, air energy water heater, electric sand baking machine, jaw crusher, cleaning machine, drying equipment (electricity), electric sand baking machine, double magnetic separator, high temperature purification device, etc.
Description of the main process flow.
1) Unloading The quartz raw ore packaged in tons of bags is transported to the factory by vehicle and unloaded in the raw material warehouse. The raw materials of the project are in the form of blocks, packed in tons of bags, and there is basically no dust in the unloading process.
2) Picking After manual picking, the ore wrapped in yellow impurities on the surface layer is selected, that is, yellow skin.
3) washing the purchased raw ore for washing, the purpose of washing is to remove a large number of clay minerals contained in the gravel, and remove the water after washing by draining. After sedimentation treatment of washing water, the supernatant is taken and recycled.
4) Drying After washing, a large amount of water is removed from the raw ore through preliminary air drying, and then dried in an electric drying equipment. The cooling method after drying adopts natural cooling cooling.
5) Coarse crushing: The rough quartz block (50 300mm) after picking, cleaning and drying is crushed to 50-100mm by jaw crusher.
6) Fine crushing The crushed stone is further crushed by the hammer crusher, and the particle size of the crushed stone after fine crushing is 10-20mm.
7) The crushed gravel in sand making, vibrating screening and magnetic separation is further crushed to 50 170 mesh by the crushing and sand making integrated system. The ore after sand making is screened, the particles that exceed the size of the specification continue to be crushed, the particles that meet the specifications enter the flotation process, and the particles smaller than the size of the specifications are collected as by-products. Sand making, screening process and primary magnetic separation are located in the same equipment. The fine sand after vibrating screening passes through the magnetic separation equipment, using the magnetic differences of various ores or materials, removing the weak magnetic impurities such as hematite, limonite and biotite and the strong magnetic minerals dominated by magnetite. Sand making, screening process and magnetic separation are carried out in the integrated sand making system.
8) flotation quartz sand is manually poured into the trough of the flotation machine, pure water, flotation agent (sulfuric acid, eighteen amine, oleic acid) is added, the hydrophobicity of impurity minerals in the quartz sand is enhanced, and the hydrophobic minerals are brought to the surface of the slurry (floating) by using the bubbles generated, and the scraper on the flotation machine automatically removes the suspended layer of the surface layer of the slurry from the slurry system through water flow agitation. The flotation slag is continuously discharged through the overflow port, and the purpose of reducing the content of impurity elements in the quartz sand sample can be achieved by flotation method. The flotation process uses pure water heated by an air energy water heater at a temperature of around 60. The flotation time is about 15h。Flotation will produce fine sand (about 95%) and tailings (about 5%).
The quartz sand flotation section mainly removes mica, feldspar and iron-containing mineral impurities. The floatability of mica is good, and its zero electric point is 04. Quartz zero electric point is 13-3.7. The surface of mica is negatively charged, and a small amount of charge on the surface of quartz is positively charged or uncharged, and the amine cation collector can adsorb mica and float out with the bubbles. Sodium anionite oil sulfonate is used as the collector, and the iron-containing minerals are floated and discharged in the water under weak acidic conditions. The physical and chemical properties of quartz and feldspar minerals are comparable, and only the aluminum ions exposed after feldspar dissociation make them different from quartz surface properties. The feldspar surface is negatively charged, and the activator is combined with aluminum ions to form a precipitate that covers the feldspar surface, making it hydrophobic. Under the adsorption of amine cationic collectors, the hydrophobic water is floated and discharged. The flotation ore is washed directly in the reactor with pure water twice.
9) Pickling. With acid
The acid matching of the project is divided into two situations: new acid and ** acid. The new acid is pumped from the raw material barrel to the acid mixing kettle by pump pressurization through the conveying pipeline, and then mixed and configured according to the ratio of 3:1 for pickling. The first acid is to pump the mixed acid that comes out after pickling into the first acid tank, and then test the mixed acid content, and then fill the new 47% hydrofluoric acid and 37% hydrochloric acid into a pickling solution that meets the requirements for pickling.
Pickling The pickling of the project uses a mixture of hydrochloric acid and hydrofluoric acid to pickle, with a mass ratio of 3:1. The mixed acid is pumped into the closed pickling reactor through the pipeline, and then the quartz sand is fed through the closed pipeline, heated to 80 90 and then kept at a constant temperature for 18 26 hours, and the pickling reactor rotates continuously in this process, so that the quartz sand is in full contact with the acid solution to ensure the effect of pickling.
The pickled semi-finished quartz sand is deacidified directly in the current reaction tank. Deacidification uses the method of filtration to extract the mixed acid from the current reaction tank, and the separated mixed acid is pumped to the acid return tank.
The mixed acid, semi-finished quartz sand and pickling sediment carried away by the quartz particles are left in the reaction tank for water washing. Because the bottom layer of the tank has a filter plate design, and the filter plate is provided with a high-density screen, which can prevent the quartz particles from passing through, so the mixed acid that is extracted does not contain these pickling sediments and can be reused.
Pickling is mainly to remove the iron element on the surface of quartz sand particles, the amount of single pickling raw material quartz sand relative to hydrofluoric acid is far excessive, the role of hydrofluoric acid is only by dissolving the surface of quartz sand (with so, reaction) and widening the surface slit and then making hydrochloric acid can fully react with the surface iron element, to achieve the purpose of iron removal and decolorization, so that the quartz sand becomes white, and to ensure that the material pickling meets the product requirements by controlling the time.
The addition ratio is 1t sand with hydrochloric acid 036t, hydrofluoric acid 012t, the mass concentration of hydrochloric acid in the mixed acid solution is about 285%, hydrofluoric acid mass concentration is about 108%。
After the pickling wastewater and acid gas are discharged, the remaining substances in the pickling device are a small amount of acid, and the quartz sand after pickling is cleaned with pure water to the pickling device to remove most of the acid and pickling sediment attached to the surface of the quartz sand. After the cleaning is completed, the negative pressure vacuum is used for dehydration, so that the moisture content of quartz sand is reduced to about 10%.
10) Drying: Put the ore into the electric sand roasting machine to dry, the drying temperature is about 200, and the drying adopts electric heating; Drying time is about 2h; After drying, it is transferred out of the dryer and indirectly cooled by circulating water.
11) Secondary magnetic separation Fine sand through magnetic separation equipment, the use of various ores or materials of magnetic differences, the removal of iron-containing strong magnetic substances.
12) chlorination purification will be selected ore into the high temperature chlorination furnace for heating, the heating temperature is 1050, the heat source is electricity, the feeding mode is conduit transmission, the raw material ore is transported from top to bottom, at the same time HCL gas is transported from bottom to top, the impurities such as alkali metal, alkaline earth metal and residual inclusions on the surface of quartz particles react with *** at high temperature to form gaseous chloride, and the high temperature gas flow will take away the chloride of these impurity elements (mainly calcium chloride, iron chloride, aluminum chloride, sodium chloride, etc.), So as to achieve the purpose of deep purification.
The materials in the high-temperature purification section of this project are only high-quality and high-purity quartz ores, which are inorganic, so the chlorination and purification section of this project does not consider the generation of dioxin waste.
There are two stages in the chlorination and purification process: reaction and escape.
Reaction stage: The impurity ions (Al3+, Fe3+, etc.) in the crystal lattice of quartz sand instead of Si4+ and the corresponding cations (K+, Na+, etc.) that play a role in charge compensation in the lattice void are immediately transformed into free states, and react with HCl to form metal chlorides such as AlCl3. The thermal defects inside the quartz lattice are in the dynamic equilibrium of continuous generation and recombination under the high temperature vibration, and the migration movement of the defects is originally completely disordered, because the concentration gradient is formed on the surface and inside, under the action of this external force field, the thermal defects inside the quartz slowly move towards the surface, which is conducive to the gradual reduction of the impurity defects inside the quartz.
Evolution stage: The water generated in the reaction stage and some metal chlorides with a boiling point lower than the roasting temperature volatilize and escape from the quartz surface and diffuse into the system, resulting in a low concentration of quartz surface products, which is conducive to the right shift of the equilibrium of the reaction. Limited by the migration rate of thermal defects and other factors, it is difficult for Schottky defects generated in quartz sand to completely migrate to the surface, while lattice impurities on or near the surface of quartz sand may be purified during chlorination roasting.
The purified quartz is cooled and cooled by indirect circulation of cooling water in the purification furnace.
13) Inspect the packaging
The purified ore is sampled to ensure that the product meets the quality requirements, the unqualified product is returned to the pickling process for reprocessing, and the qualified product is packaged and put into storage.
14) Purified water preparation
The pure water system of this project is divided into five units: pretreatment unit, primary reverse osmosis unit, secondary reverse osmosis unit, EDI unit and control unit.
The specific process flow is as follows:
Raw Water Tank Raw Water Pump Ultrafiltration Filter Security Filter Level 1 High Pressure Pump Level 1 RO Unit Level 1 Pure Water Tank Level 2 High Pressure Pump Level 2 RO Device Level 2 Produced Water Tank EDI Booster Pump EDI Unit Ultrapure Water Tank Water Point.
Pretreatment unit The pretreatment adopts an automatic control mode, which is composed of a raw water tank, a raw water pump, an ultrafiltration filter and a chemical dosing device. The function of pretreatment is to treat the raw water that does not meet the inlet conditions of the reverse osmosis membrane, remove the suspended solids, colloids and some organic matter in the raw water, improve the water supply environment, make it meet the inlet conditions of entering the RO system, reduce and delay the pollution of the membrane, and prolong its life.
Reverse osmosis unit.
The primary RO and secondary RO units are fully automatic control and are the main desalination devices of this water treatment system, mainly including reverse osmosis device, pure water tank, reverse osmosis cleaning device and high-pressure pump.
Reverse osmosis is one of the most widely used desalination technologies in water treatment system equipment, with extremely high desalination capacity, and safe and flexible operation, and simple operation. It is the core part of the whole equipment, reverse osmosis membrane is a semi-permeable membrane that only allows water molecules to pass through and does not allow other solutes to pass through, its pore size < 10 10-10m, so it can filter out most of the various inorganic salt ions. More than 98% of the inorganic salts in the raw water can be removed through the first-stage reverse osmosis system, and more than 90% of the inorganic salts in the first-class produced water can be removed by the second-stage reverse osmosis system.
EDI unit.
EDI works by exchanging hydroxyl ions or hydroxide ions to unwanted ions and then transporting these ions into the wastewater stream, the EDI unit consists of an EDI water supply pump, an EDI module, a power supply, an EDI ultrapure water tank.
The ion exchange reaction takes place in the purification chamber of the assembly, where the anion exchange resin releases hydroxide ions (OH-) and anions are obtained from dissolved salts (e.g., chloride, Cl-). Similarly, cationic alternating resins release hydrogen ions (H+) and cations are obtained from dissolved salts (e.g., sodium, Na+).
A direct current (DC) electric field is applied through an anode (+) and a cathode (-) placed at one end of the assembly.
The voltage drives these absorbed ions along the surface of the resin sphere and then through the film into the concentrated water chamber. Negatively charged anions (e.g., oh-, cl-) are attracted to the anode (+) and these ions pass through the anion-selective film and into the adjacent brine chamber without passing through the adjacent cation-selective film and remaining in the brine chamber and must be properly disposed of. In the freshwater chamber, positively charged cations (e.g., H+, Na+) are attracted to the cathode (-).
These ions pass through the cation-selective film into the adjacent water concentration chamber, where they are blocked by the adjacent anion-selective film and are properly disposed of. In the brine chamber, electrical neutrality is still maintained. The ions transported from both directions neutralize each other. The current flowing from the power supply is proportional to the number of ions moved.
Both streams (H+ and OH-) trend ions are transported and added to the required current.
After passing through two different types of chambers, the ions in the purification chamber are depleted and collected into the adjacent brine stream. The use of ion exchange resins in purification chambers and/or brine chambers is a key to Electropure EDI technology and patents. An important phenomenon also occurs in the purification chamber, where the electrochemical "decomposition" of water in a given region with a high potential gradient can cause the water to produce large amounts of H+ and OH- ions. The H+ and OH- ions produced in these regions are continuously regenerated in the hybrid ion exchange resin, forming a thin film that does not require additional chemical agents.
Information**: Jinhua Municipal Bureau of Ecology and Environment.
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The 2nd Anhui International Quartz Industry Conference and Exhibition 2024.