What is grinder lab?
In the laboratory, solid samples generally need to be pretreated before they can be tested, analyzed, and other operations. Among the pretreatment steps, grinding is the most important part. If the grinding is not thorough, it will bring trouble to the subsequent operation and the resulting experimental data will be inaccurate. Proper sample pre-treatment methods are critical to the accuracy of analytical results. Therefore, a grinder lab
is very necessary.
Why should we pretreat raw material before grinding?
a. Separates the measured component from the complex sample into a form that is easy to measure.
b. Remove the substances that will influent the analytical measurements.
c. If the measured component is difficult to detect by the selected analytical method, it needs to be quantitatively transformed into another easily detectable compound by sample derivatization.
d. In the testing operation, the samples can be divided into test samples, original samples, and average samples. Among them, the average sample obtained by the quadratic method gets more accurate experimental data results than others. Before conducting the quadratic method with the average sample, it is needed to finely grind and homogeneously mix the samples to ensure the results of the experimental testing are accurate. Thus, the solid sample testing experiments need to carry out the pre-grinding treatment.
e. Increase the relative surface area of the sample to speed up the chemical reaction. Since the molecular distribution of solid samples is usually fixed, grinding of solid samples can effectively adjust the sizes of particles, change the granularity distribution of particles, increase the surface area of specific particles, break the agglomeration of particles, and reduce reaction times. For example, individual components can be obtained from the composite material during pretreatment, which facilitates the further preparation of the refined material.
f. Enables a more uniform sample distribution. After the solid sample is ground into a certain fineness of powder, the components inside can be evenly distributed, making the subsequent sample extraction more representative.
g. Particle size and shape analysis experiments. When analyzing solid samples for particle size and shape, the experiment personnel must grind the samples to a certain fineness. In this way, they can obtain experimental data accurately.
h. Research on new materials and hybrid synthesis. In scientific experiments for the synthesis of new materials, the homogeneous mixing of materials is very important and directly influences the properties of the new material. To mix several solid samples, it is necessary to meticulously grind the samples.
i. The need for test experiments. There are also requirements for solid sample size in detection experiments such as IR detection, XRF, and electron microscope. For example, microwave ablation requires solid samples that are below 500 μm, soxhlet extraction that are below 500 μm, IR spectroscopy that are below 150 μm, and X-fluorescence spectroscopy that are below 100 μm.
Methods for sample pre-treatment
a. Pulverizing, grinding, and polishing
Using these methods can help to increase the contact area between the solid and liquid or gas, speed up the reaction rate, complete the reaction rate, and improve the conversion rate, utilization, and leaching rate of raw materials.
Methods to increase the contact area:
a) Solids can be crushed and ground (it is generally ground with a mortar and pestle in the laboratory);
b) Liquids can be sprayed with wine;
c) Gases are used in porous dispersers.
Leaching, or dissolution, is an operation in which a suitable amount of reagent or solvent is added to a solid. The purpose of this operation is to separate water-soluble and non-water-soluble substances.
Water leaching: refers to the reaction or dissolution of substances in contact with water, which aims to separate water-soluble and non-water-soluble substances.
Acid leaching: This method generally uses sulfuric acid, hydrochloric acid, concentrated hydrochloric acid, and nitric acid to soak the sample. The purpose of this method is to dissolve metals and metal oxides, adjust and remove the pH of certain ions, etc.
Alkali leaching: This method pretreats the sample with sodium hydroxide solution. The purpose of this method is to remove oil, dissolve acidic oxides, dissolve aluminum and its compounds (or zinc and its compounds), and adjust pH.
Alcohol leaching: This method is usually used to extract organic matter.
c. Improve the leaching rate
To improve the leaching rate, you should consider the reactant contact area, contact opportunity, temperature, reactant concentration, solvent properties, etc, and adjust by these factors. Or you can extend the leaching time and leach the liquid several times to help improve the leaching rate.
Chemical ignition removes flammable impurities or facilitates the initial transformation of raw materials. Chemical ignition in the extraction of iodine from kelp is used to remove flammable impurities and convert organic iodine into iodized salt.
The methods of cauterization, roasting, or calcination can change the structure and composition of samples so that some substances can be dissolved; and make some impurities oxidized and decomposed at high temperatures, such as calcined kaolin and limestone. (In the laboratory, cautery is usually carried out in a crucible with direct heating by an alcohol lamp).
e. Stirring and heating
In the raw material pretreatment, stirring and heating can accelerate the dissolution, increase the contact area of the reactants, and speed up the reaction rate.
The addition of catalysts can greatly improve the reaction rate and reduce energy consumption but does not affect the chemical equilibrium. When using the catalyst, you should pay attention to the active temperature of the catalyst and prevent the catalyst from "poisoning" (the phenomenon that the activity and selectivity of the catalyst are significantly reduced or lost by the trace impurities contained in the reaction materials).
g. Surface pretreatment
a) The oil on the metal surface can be removed with alkali;
b) The metal crystals can be polished by mechanical method;
c) The surface oxides can be removed by chemical method.
Types of grinder lab
Grinding is a very important step in the pre-treatment of solid samples in the laboratory. Many experiments require grinder lab equipment, such as particle size and shape analysis of materials, infrared and electron microscopy testing experiments, etc. The following are types of lab grinder used to crush and grind solid samples in the laboratory.
Grinding by hand or teeth
Since ancient times, people have known how to break up food before eating to facilitate digestion, and the most common method is to crush it by hand or chew it with teeth. However, by using this method for experiments, it is easy to cause contamination to the sample and is not meticulous enough. It is not recommended for laboratory use.
Grinding with the help of tools
As an old saying goes, “a workman must first sharpen his tools if he is to do his work well”. The grinding of solid samples becomes easier than before with the help of tools. The grinding tools like sticks, hammers, and mortars are very common in laboratories.
Sticks and hammers are very common tools used in our daily life. The mortar is often used in the laboratory. A mortar is a bowl-shaped vessel made of hard material. It is accompanied by a pestle. The material of mortar and pestle are the same. They are usually made of iron, ceramic, agate, alumina, etc.
When grinding samples, you should put the material into the mortar first, making sure that the volume of the sample does not exceed one-third of the mortar. Then, you should pound and crush the sample with a pestle until it was ground to the desired state.
Use laboratory grinder machine for grinding
The above grinding methods are manual grinding, which is certainly not as efficient and accurate as laboratory grinder machines
. The use of lab grinder machine
has been around for many years. from the early mock mortar type grinder to the later jaw grinder, cutting grinder, rotary grinder, knife grinder, disc grinder, to the current popular planetary ball mill, shock vibration ball mill, and lab mill grinders
are also constantly improving and developing to meet the increasingly stringent experimental requirements.
With the increasing demand for laboratory grinding, lab mill grinders
have been continuously improved and developed to meet the increasingly stringent experimental requirements. In the early stage, the mortar-type grinder which can simulate a mortar was developed. Then, laboratory grinding mills like jaw grinder, cutting grinder, rotary grinder, knife grinder, and disc grinder were designed and used. Later, current popular lab grinders are planetary ball mill, shock vibration ball mill, etc.
Sample grinder for lab
Laboratory sample grinders work by vibration grinding. The tested material is put into the breaking rings and breaking hammer in the feeder bowl. When the bowl rotates at high speed, it causes strong vibration and friction, and the material inside is ground and crushed by the crushing ring and hammers. The material can be rapidly ground into 80-200mu powder samples in 2-6 minutes and can be used directly for testing. Feeding bowl is made of different materials, such as manganese steel, common steel, wear-resistant alloy, tungsten carbide, etc. Depending on the material of the bowl, the hardness of the mineral is also different.
How to buy grinder lab?
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